40results about How to "Less power conversion stages" patented technology

The invention discloses a DC residential energy router based on a multi-port converter and a control method thereof. The energy router is characterized in that the energy router is composed of four H bridge modules, two-way buck / boost converter modules BB1 and BB2, four external series inductors, and a high-frequency four-winding transformer; driving signals used to control on-off of full-control power devices in the converter modules BB1 and BB2 are obtained by means of pulse width modulation; and driving signals used to control on-off of full-control power devices in the H bridge modules are obtained by means of single phase shift modulation. The energy router integrates photovoltaic energy, stored energy, a power grid, and a residential load with different voltage grades. Two-way power flow between stored energy and the power grid is realized. Maximum use of renewable energy, reduction in power exchange with the power grid, charge and discharge based on stored energy, input source use priority, control on port voltages and power balance control in the system are realized.

The invention discloses a single-stage bidirectional isolation AC-DC converter, and belongs to the field of an electronic power electronic converter. The structures of three converters are each composed of single-phase AC sources, DC sources, Boost inductors, phase shift inductors, bus capacitors, transformers, primary power switch tubes, secondary power switch tubes and the like. The Boost inductors are connected to leg midpoints such that the integration of a bidirectional Boost PFC converter with a bridge type bidirectional converter is realized, through single-stage power transformation, two functions of PFC and isolation DC-DC transformation can be realized, and bidirectional flowing of energy is realized. The single-stage bidirectional isolation AC-DC converter, has the advantages of small power loss, high transformation efficiency, small switching loss, capability of realizing the bidirectional flowing of the energy, and the like, thereby being especially suitable for V2G and power network-storage battery energy storage systems.

The invention discloses a Cuk-converter-based high-frequency isolated three-level AC-AC converter. In the converter, two coupling capacitors in a non-isolated Cuk three-level topology are both divided into two parts between which a serial isolated transformer is inserted; the middle connecting points of the primary sides of the two transformers are connected with the middle points of two bidirectional power switch tubes on the left side and the middle points of the two bidirectional power switch tubes on the right side respectively; and a power supply end and an output end form a circuit topological structure capable of converting an unstable high-voltage current into a stable or adjustable common-frequency sinusoidal alternating current by combining an input filter and an output filter respectively. In the invention, the power conversion stage number is small, fewer power switch elements are used, a bidirectional power current can be realized, the converter has an electrical isolation property, the spectral characteristic of the front end voltage of the output filter is desirable, the conversion efficiency and power density are improved, a voltage regulation range is wide, voltage boosting and reducing regulation can be realized, and the volume and weight of the output filter can be realized.

The invention provides a full-bridge current-source high-frequency isolation-type three-level inverter. The full-bridge current-source high-frequency isolation-type three-level inverter consists of an input direct-current power supply, voltage-dividing capacitors, a full-bridge current-source high-frequency isolation-type three-level conversion unit, a cyclic wave converter, an output filter and an output alternating-current load which are sequentially connected with one another, wherein on the basis of the traditional full-bridge current-source inverter, two capacitors are connected to two ends of the input direct-current voltage source in parallel to divide the voltage, so that three levels of Ui, Ui / 2, minus N1U0 / N2 can be generated on the front end of a transformer, the voltage stress on a switch tube can be reduced, and the application range of the current-source high-frequency isolation inverter can be enlarged. The full-bridge current-source high-frequency isolation-type three-level inverter has two levels of power transformation (direct-current (DC)-high-frequency alternating-current (HFAC)-low frequency alternating current (LFAC)) and has the advantages of bi-directional power flow, low voltage stress on a switch device, good spectrum characteristics on the front end of the filter, small size of the output filter, high power density and capability of realizing the high-frequency electrical isolation between the alternating-current load and the direct-current power supply.

The invention provides a high-frequency isolation-type five-level inverter. The high-frequency isolation-type five-level inverter consists of an input direct-current power supply unit, voltage-dividing capacitors, a high-frequency isolation-type five-level conversion unit, a high-frequency isolation transformer, a cyclic wave converter, an output filter and an output alternating-current load, wherein on the basis of a full-bridge inverter, four capacitors are connected to two ends of an input direct-current voltage source in parallel to divide the voltage, so that five levels of Ui / 2, Ui / 4, 0, minus Ui / 4, minus Ui / 2 can be generated on the front end of the transformer, the five levels also can be sensed by a transformer side edge, the voltage stress on a switch tube can be reduced, and the waveform quality of the output voltage can be improved. The inverter has two levels of power transformation (direct current (DC)-high frequency alternating current (HFAC)-low frequency alternating current (LFAC)) and has the advantages of bi-directional power flow, low voltage stress on a switch device, good voltage spectrum characteristics on the front end of the output filter, small size of the output filter, low voltage stress on the switch tube and capability for electrically isolating the alternating-current load and the direct-current power supply in a high-frequency manner. The inverter can be applied to the application field with higher voltage and large power.

The invention provides a matrix type motor driving system based on bidirectional wireless electric energy transmission. In the system, an energy transmission mode adopts coupling coil type wireless electric energy transmission, and a signal transmission mode adopts a wireless communication technology. According to the invention, one-step power conversion from high-frequency alternating current tolow-frequency alternating current is realized by utilizing a direct matrix converter, so that a direct-current bus capacitor with high failure rate is removed, and the number of power conversion stages is reduced so as to substantially improve the reliability and the power density; two-way power transmission capacity is achieved through coordination control of converters in a vehicle body and wheels, so that braking energy is fed back to a battery side so as to improve the energy utilization efficiency; and the application range of the designed matrix type motor driving system based on bidirectional wireless power transmission is not limited to hub motors, and the matrix type motor driving system based on bidirectional wireless power transmission also has important reference value for special industrial applications with wireless requirements, such as joint driving motors of robots.

The invention provides a high-frequency isolated type three-level inverter based on a push-pull converter. The high-frequency isolated type three-level inverter is composed of an input direct-current power source unit, an input filter, a push-pull three-level inversion unit, a high-frequency transformer, a frequency converter, an output filter and an output alternating current load which are connected in sequence. The input direct-current power source unit is connected with one end of the input filter. The other end of the input filter is connected with one end of the push-pull three-level inversion unit. The other end of the push-pull three-level inversion unit is connected with a primary winding of the high-frequency transformer. A secondary winding of the high-frequency transformer is connected with the input end of the frequency converter. The output end of the frequency converter is connected with the input end of the output filter. The output end of the output filter is connected with the output alternating current load. The high-frequency isolated type three-level inverter has the advantages that the number of levels of power conversion is small, few power switch elements exist, voltage stress of a power switch tube is low, bidirectional power current and high-frequency electric isolation are achieved, and the voltage spectral characteristic of the front end of the output filter is good.

The invention discloses a two-stage non-isolation photovoltaic grid-connected inverter. The two-stage non-isolation photovoltaic grid-connected inverter comprises a first direct current bus capacitor, a second direct current bus capacitor, a direct current power conversion circuit, and a full bridge power conversion circuit, the first direct current bus capacitor is connected with a photovoltaic assembly string and an input terminal of the direct current power conversion circuit in sequence, the second direct current bus capacitor is connected with an output terminal of the direct current power conversion circuit, the first direct current bus capacitor and the second direct current bus capacitor are connected in series and then connected with an input terminal of the full bridge power conversion circuit, and an output terminal of the full bridge power conversion circuit is externally connected with a power grid. The invention also discloses a control method thereof. According to the two-stage non-isolation photovoltaic grid-connected inverter and the control method thereof, the voltage stress of the direct current bus capacitors is reduced, only a part of power passes through the direct current power conversion circuit, the power conversion stage number is small, and the power loss is small; double-buck topology is employed, hidden risks of gating of bridge arms can be prevented, and the reliability is high; freewheeling is realized via an independent diode, a power switch tube can employ an MOSFET, and the conversion efficiency of the grid-connected inverter can be improved.

The invention discloses a two-stage non-isolated full-bridge grid-connected inverter, which comprises a first direct-current bus capacitor, a second direct-current bus capacitor, a direct-current power conversion circuit, a first power switch tube, a second power switch tube, a third power switch tube, a fourth power switch tube, a fifth power switch tube, a sixth power switch tube, a first power diode, a second power diode, a third power diode, a fourth power diode, a first filter inductor, a second filter inductor and a filter capacitor, wherein the power switch tubes and the power diodes have a plurality of structures and connection modes. The two-stage non-isolated full-bridge grid-connected inverter has the characteristic that a series form is adopted by partial power switch tubes and power diodes, so that the voltage stress of a power device is only equal to the voltage of the first direct-current bus capacitor or the voltage of the second direct-current bus capacitor. The voltage stress of the power switch tubes and the power diodes is reduced, so that the cost is reduced; the efficiency is improved; and the problems in the prior art are solved.

The invention discloses a forward five-level inverter, comprising an input direct current power supply, a voltage dividing capacitor, a forward five-level conversion unit, a cycle converter, an output filter and an output alternating current load. Through change of the type of the cycle converter, a circuit topology family of a half-wave rectification forward five-level inverter and a full-wave rectification forward five-level inverter is obtained. The forward five-level inverter provided by the invention has the advantages of few power conversion stages, bidirectional power flow, good output filter front-end voltage spectral characteristic and the like, the conversion efficiency and the power density are improved, the size and the weight are reduced, the voltage stress of a switching device can be reduced, and high-frequency electrical isolation of the alternating current load from the direct current power supply is realized.

The invention provides a high-frequency isolated type boost three-level inverting circuit which is composed of a Boost inverting circuit and a flyback type energy feedback circuit. The Boost inverting circuit is composed of an input direct-current power supply unit, an input filter, a high-frequency inverter, a high-frequency transformer, a frequency converter, an output filtering capacitor and an output alternating-current load which are sequentially connected. A Boost converter can only increase the voltage and can not decrease the voltage, so that the output voltage can not be decreased, and the voltage can not meet the requirement for the output sine waveform. In order to ensure the quality of the output sine waveform in the period and solve the problem of the orientation of reactive energy of the output filtering capacitor and the load, the high-frequency electrical isolation flyback type converter energy feedback circuit is added between the output load and an input power supply. The inverter has the advantages that the number of power conversion stages is small, the number of power switching devices is small, input ripple waves are small, the voltage stress of a power switching tube is low, the dual-directional power stream and high-frequency electrical isolation are achieved, and the spectrum characteristic of the voltage at the front end of the output filter is good.

The invention provides a three-phase alternating current-alternating current (AC-AC) direct frequency converter and a control method thereof. The three-phase AC-AC direct frequency converter comprises a three-phase power supply, a filter, a main circuit and a buffer circuit, and is characterized in that the power supply is sequentially connected with the filter and the main circuit, and the main circuit is connected with the buffer circuit. The control method for the three-phase AC-AC direct frequency converter comprises a sinusoidal pulse width modulation (SPWM) control mode and a hysteresis current control mode. The converter is simple in topology structure; and the control method is simple, practical and high in reliability, and comprises a few power conversion stages.

The invention discloses a current source type three-level AC / AC converter. The current source type three-level AC / AC converter is formed by an input alternating current power supply, a voltage-dividing capacitor, a high-frequency isolation type three-level conversion unit, a frequency converter, an output filter and an output alternating current load which are connected in sequence. According to the converter, on the basis of a traditional AC / AC converter, the two ends of the input alternating current power supply are in parallel connection with two capacitance partial voltages, the front end of the converter can generate three levels including U, U / 2 and -Uo / n (n=N2 / N1= ), voltage stress of a switch tube is reduced, and output voltage waveform quality is improved. The current source type three-level AC / AC converter has the advantages that voltage stress of a switch device is small, front end voltage spectral characteristics of the output filter are good, the size of the output filter is small, and an alternating current load and alternating current power supply high-frequency electrical isolation can be achieved; and the current source type three-level AC / AC converter can be applied to the application occasions with high voltage and high power and is wide in application prospect.

The invention discloses a high-frequency isolation type three-level inverter. The high-frequency isolation type three-level inverter comprises an input direct current power supply, voltage sharing capacitors, a full-bridge current source type high-frequency isolation type three-level conversion unit, a cycle converter, an output filter and an output alternating current load which are connected insequence; on the basis of the conventional full-bridge current source type inverter, two voltage sharing capacitors are connected at the two ends of an input direct current voltage source in parallel,so that the front end of a transformer can generate three levels of U, U / 2, -N<1>U<0> / N<2>, thereby lowering voltage stress of a switching tube, and expanding the application range of the current source type high-frequency isolation inverter. The high-frequency isolation type three-level inverter has the advantages of two-stage power conversion (direct current DC-high freqeucny alternatingcurrent HFAC-low freqeucny alternating current LFAC), bidirectional power flow, low voltage stress of the switching device, high voltage spectral characteristic at the front end of the output filter,small size of the output filter, relatively high power density, and capability of realizing high frequency electrical isolation of an alternating current load and a direct current power supply.

This invention discloses a Zeta three-level AC-AC converter, which converts a DC Zeta topological single-way switch tube to a dual-way switch tube, adds a supply level mode branch and a dual switch tube isoalting it and adds a zero-level mode dual-switch tube in front of the output filter combined with a non-complementary control strategy, and input and output filters are added to the supply and output ends to make up of a circuir topological structure of stable and adjustable same frequency and high quality sine AC circuit, the power conversion series of this invention is less and dual power flow can be realized, the voltage spectrum character in front of the output filter is good, conversion efficiency and power density are increased, the step regulation can be realized and the volume and weight of the output filter can be reduced and the output waveform quality is increased.

The invention discloses a high-frequency isolation type tri-level inverter based on a forward converter. The high-frequency isolation type tri-level inverter based on the forward converter is composed of an input direct-current power supply (Ui), a dividing capacitor, a high-frequency isolation type forward tri-level conversion unit, a frequency converter, an output filter and an output alternating-current load, wherein the input direct-current power supply (Ui), the dividing capacitor, the high-frequency isolation type forward tri-level conversion unit, the frequency converter, the output filter and the output alternating-current load are connected in sequence. The high-frequency isolation type tri-level inverter based on the forward converter has two stages of power conversion (direct current DC--high frequency alternating current HFAC--low frequency alternating current LFAC), and has bidirectional power flow, the front end of the output filter is good in voltage spectral characteristic, and the high-frequency isolation type tri-level inverter based on the forward converter has high power density, can reduce the voltage stress of a switching element, and can achieve high-frequency electrical isolation of alternating current load and direct-current power supply.

The invention discloses a high-frequency isolation five-level inverter, which is composed of an input direct current power supply, voltage dividing capacitors, a high-frequency isolation five-level conversion unit, an output frequency converter, an output filter and an output alternating current load connected in sequence; according to the inverter, based on the full-bridge inverter, the voltage is divided by connecting two capacitors at two ends of the input direct current voltage source in parallel, thus the front end of the transformer can generate five levels including Udc, Udc / 2, 0, -U / dc / 2 and -Udc, and the five levels can be simultaneously inducted at a transformation secondary, the voltage stress of a switch tube is reduced, and meanwhile, the waveform quality of output voltages is improved. The inverter has the advantages of two-stage power conversion (DC-HFAC-LFAC), bidirectional power flow, low switch device voltage stress, good frequency spectrum characteristic of front-end voltage of output filter, small size of output filter, and high-frequency electrical isolation of AC load and DC power supply. The inverter is low in switch tube voltage stress, and can be applied to the application fields with higher voltage and large power.

The invention provides a high-frequency isolation three-level inverter. The high-frequency isolation three-level inverter comprises an input direct-current power supply, a voltage dividing capacitor, a high-frequency isolation Buck-Boost type three-level conversion unit, a cycle converter, an output filter and an output alternating-current load which are connected with one another. According to the converter, on the basis of a traditional full-bridge high-frequency isolation Buck-Boost type inverter, two capacitors are connected to the two ends of an input direct-current voltage source in parallel for voltage division, so that three levels can be generated at the front end of a transformer, the voltage stress of a switching tube is reduced, and the application range of the high-frequency isolation Buck-Boost type inverter is widened. The high-frequency isolation three-level inverter has the advantages of two-stage power conversion (direct current (DC)-high frequency alternating current (HFAC)-low frequency alternating current (LFAC), bidirectional power flow, low voltage stress of a switching device, good voltage spectrum characteristic at the front end of the output filter, small size of the output filter, relatively high power density, capability of realizing high-frequency electrical isolation of an alternating current load and a direct current power supply, suitability for a micro-grid and the like.

The invention discloses a flyback high-frequency isolated three-level inverter. The circuit structure of the inverter is composed of an input DC power supply, an input filter, a high-frequency isolated flyback three-level conversion unit, a cycloconverter, an output filter and an AC load; The function of converting DC voltage into the required stable and high-quality sinusoidal AC voltage. By changing the type of the high-frequency isolated flyback three-level conversion unit and the cycloconverter, a single-tube flyback type, a double-tube flyback type, a half-bridge flyback type, and a full-bridge flyback type can be obtained. Family of circuit topologies for flat inverters. The invention has good characteristics such as simple circuit topology, two-stage conversion of bidirectional power flow, small voltage stress of power switch tube, good voltage spectrum characteristics at the front end of output filter, small size of output filter, strong load adaptability, etc., and is suitable for high voltage input occasions .

The invention discloses a multi-port converter for electric automobile cluster charging and discharging and a control method of the multi-port converter. The multi-port converter is characterized in that the multi-port converter is totally provided with n ports; (n-1) ports from the first port to the (n-1)th port in the n ports are respectively used for being connected with an electric automobile battery; and the n-th port in the n ports is used for being connected with a direct current bus in a direct current micro grid. The control method of the multi-port converter is characterized in that the duty ratio of each switch tube is obtained through calculation; driving pulses corresponding to each switch tube are formed by utilizing the duty ratio obtained through calculation for controlling the on-off state of each switch tube; and the discharging control and the charging control on the electric automobile battery are further realized. The multi-port converter and the control method are used for electric automobile cluster charging and discharging control, and the interaction function between an electric automobile and an electric network is fully achieved.

The invention discloses single-stage bidirectional isolation AC-DC converters with three structures, belonging to the field of power electronic converters. The structures of the three converters are all composed of a single-phase AC source, a DC source, a Boost inductor, a phase-shift inductor, a bus capacitor, a transformer, a primary and secondary power switch tube, and the like. By connecting the Boost inductor at the midpoint of the bridge arm, the integration of the bidirectional Boost PFC converter and the bridge bidirectional converter is realized. The single-stage power conversion can realize the two functions of PFC + isolated DC-DC conversion, and the energy can flow in both directions. The invention has the advantages of small power loss, high conversion efficiency, small switching loss, and can realize bidirectional flow of energy, and is especially suitable for V2G and grid-battery energy storage systems.

The invention provides a method for suppressing power frequency ripples of a wireless power supply system through phase modulation, and the power frequency ripples are that the output voltage of a rectification line contains voltage fluctuation which is two times of the power frequency. According to the method for suppressing the power frequency ripple of the wireless power supply system through phase modulation, the PWM phase of a full-bridge inverter circuit of a high-frequency DC / AC is modulated according to the change of the output voltage of a power frequency AC / DC rectifying circuit, and the purpose of suppressing the influence of the power frequency ripple at the receiving end voltage or current of power is achieved. The method has the beneficial effects that the power conversion stage number is reduced, the system efficiency is improved, and the production cost is reduced.

The invention discloses a pulse load power system and a control method thereof. The pulse load power system is composed of an isolated dual-output transformation module and a non-isolated DC converter, the isolated dual-output transformation module comprises an input port and two output ports, the second output port of the isolated dual-output transformation module is connected with the input portof the non-isolated DC converter, the output port of the non-isolated DC converter and the first output port of the isolated dual-output transformation module are connected in series and serve as themaster system output port, and the master output port is connected with a pulse load. The isolated dual-output transformation module controls the voltage and input current of the first output port, and the non-isolated DC converter controls the total output voltage of the system. The system can inhibit current impact generated in the input port by pulse power effectively, the system power transmission level, the system efficiency and power density are reduced, and the system and method are especially suitable for application occasions with pulse load.

The invention provides a matrix motor drive system based on two-way wireless power transmission. In the system, the energy transmission mode adopts coupling coil type wireless power transmission, and the signal transmission mode adopts wireless communication technology. Using the direct matrix converter to realize one-step power conversion from high frequency AC to low frequency AC not only removes the DC bus capacitor with high failure rate, but also reduces the number of power conversion stages, greatly improving reliability and power density. The two-way power transmission capability is realized through the coordinated control of the converters in the car body and in the wheels, so that the braking energy is fed back to the battery side, which improves the energy utilization efficiency. The designed matrix motor drive system based on bidirectional wireless power transmission is not limited to in-wheel motors, but also has important reference value for special industrial applications with wireless requirements, such as robot joint drive motors.

The invention discloses a high-frequency isolation type three-electric-level DC-DC (direct current-direct current) convertor based on Cuk convertor. In the convertor, two coupling capacitors in a DC non-isolation type Cuk three-electric-level topology without a transformer are respectively disassembled into two capacitors, and two serially-connected transformers are respectively inserted between the two capacitors, the middle connecting point of primary sub sides of two transformers is respectively connected with the middle point of two switching tubes at left side and two booster diodes at right side, and an input filter and an output filter are respectively arranged at the input end and the output end to form a circuit topological structure which converts unstable direct current into adjustable direct current. In the invention, the power conversion stage number is less, power switching devices are less, boosting regulation can be realized, and the converter has the electrical isolation character; in addition, spectral characteristic of the voltage at the front end of the output filter is good, the conversion efficiency and power density are improved, and the volume and weight ofthe output filter are reduced.

The invention provides a single phase AC-AC (Alternating Current-Alternating Current) direct frequency convertor and a control method thereof. The single phase AC-AC direct frequency convertor comprises a power supply, a filter circuit, a main circuit and a buffering circuit, wherein the power supply U is connected with the filter circuit and the main circuit; and the main circuit is connected with the buffering circuit. The control method of the single phase AC-AC direct frequency convertor is a single polarity control method or a hysteresis current control method. The single phase AC-AC direct frequency convertor has a simple topological structure, the control method is simple and practicable, the power conversion stage number is small, and the reliability is high.

The invention discloses a two-stage non-isolated photovoltaic grid-connected inverter, comprising a first DC bus capacitor, a second DC bus capacitor, a DC power conversion circuit, and a full-bridge power conversion circuit; the first DC bus The capacitors are sequentially connected to the photovoltaic module string and the input end of the DC power conversion circuit, the second DC bus capacitor is connected to the output end of the DC power conversion circuit, and the first DC bus capacitor is connected in series with the second DC bus capacitor to the full bridge The input end of the power conversion circuit and the output end of the full-bridge power conversion circuit are externally connected to a power grid, and a control method thereof is also disclosed. The invention reduces the capacitor voltage stress of the DC bus bar; only part of the power passes through the DC power conversion circuit, the number of power conversion stages is small, and the power loss is small; the dual step-down topology is adopted, there is no hidden danger of bridge arm direct connection, and the reliability is high; The diode freewheels, and the power switch tube can use MOSFET, which is beneficial to improve the conversion efficiency of the grid-connected inverter.

The invention provides a high-frequency isolated type boost three-level inverting circuit which is composed of a Boost inverting circuit and a flyback type energy feedback circuit. The Boost inverting circuit is composed of an input direct-current power supply unit, an input filter, a high-frequency inverter, a high-frequency transformer, a frequency converter, an output filtering capacitor and an output alternating-current load which are sequentially connected. A Boost converter can only increase the voltage and can not decrease the voltage, so that the output voltage can not be decreased, and the voltage can not meet the requirement for the output sine waveform. In order to ensure the quality of the output sine waveform in the period and solve the problem of the orientation of reactive energy of the output filtering capacitor and the load, the high-frequency electrical isolation flyback type converter energy feedback circuit is added between the output load and an input power supply. The inverter has the advantages that the number of power conversion stages is small, the number of power switching devices is small, input ripple waves are small, the voltage stress of a power switching tube is low, the dual-directional power stream and high-frequency electrical isolation are achieved, and the spectrum characteristic of the voltage at the front end of the output filter is good.

The invention discloses a multi-port converter for electric automobile cluster charging and discharging and a control method of the multi-port converter. The multi-port converter is characterized in that the multi-port converter is totally provided with n ports; (n-1) ports from the first port to the (n-1)th port in the n ports are respectively used for being connected with an electric automobile battery; and the n-th port in the n ports is used for being connected with a direct current bus in a direct current micro grid. The control method of the multi-port converter is characterized in that the duty ratio of each switch tube is obtained through calculation; driving pulses corresponding to each switch tube are formed by utilizing the duty ratio obtained through calculation for controlling the on-off state of each switch tube; and the discharging control and the charging control on the electric automobile battery are further realized. The multi-port converter and the control method are used for electric automobile cluster charging and discharging control, and the interaction function between an electric automobile and an electric network is fully achieved.

The invention discloses a photovoltaic grid-connected inverter which comprises a first direct current bus capacitor branch, a second direct current bus capacitor branch, a boost converting circuit, a direct current bypass branch, a full-bridge inverter circuit and an alternating current filtering circuit, wherein the first direct current bus capacitor branch, the boost converting circuit, the second direct current bus capacitor branch, the full-bridge inverter circuit and the alternating current filtering circuit are sequentially connected in series; the input end of the first direct current bus capacitor branch is externally connected with a photovoltaic modules string; the output end of the alternating current filtering circuit is externally connected with a power grid; the direct current bypass branch is connected in parallel between the input end of the first direct current bus capacitor branch and the output end of the full-bridge inverter circuit. Meanwhile, the invention also discloses a control method for the photovoltaic grid-connected inverter. According to the photovoltaic grid-connected inverter and the control method thereof disclosed by the invention, the direct current bypass branch is introduced, so the problems in the prior art are solved.