47 results about "Wave variables" patented technology

The invention relates to a high pressure electric potential therapeutic apparatus which can output the asymmetrycomplex wave form. The high pressure electric potential therapeutic apparatus includes a power supply, a functional module, an output control, a high pressure output end, and an irregular wave form generating circuit connected in series between the power supply and the high pressure output end. The irregular wave form generating circuit includes a phase coupling booster transformer (T1) and a wave variable transformer (T2), and three groups of circuits connected in parallel between the secondary order of the wave variable transformer. The high pressure electric potential therapeutic apparatus of the invention, first is provided with a divider resistance and a high voltage diode in series by the high pressure end outputted by the high pressure, to realize the function of high pressure voltage division and attenuation; then, the elementary tandem connection wave variable transformer outputted by the high pressure realizes the addition of waveforms, thereby changing the high pressure outputting wave form. When the human body is cured, due to the abnormity of the electric potential, the physiological function of the human body can not generate the 'adopting' disease, to make the physiatrics used for a long time and maintain better therapeutic effect.

The invention relates to a stability control method for a time-delay-variable bilateral teleoperation system. Models of two main ends and an auxiliary end of the bilateral teleoperation system are established; according to three coexisting channels, each channel transmits speed and force information to the opposite side, a wave variable method is used to ensure the channel stability in each channel, and channel stability controllers are designed; and a time delay is predicted, an obtained time variable gain is input to the two channel stability controllers, and stability control of the time-delay-variable teleoperation system is realized. The method is easy to realize and apply, and can be mainly applied to stability control of the time-delay-variable bilateral teleoperation system. The method has high robustness for linear and nonlinear teleoperation systems, and the time delay prediction method can be used to obtain an extremum of a time delay change rate easily.

The invention provides a wave integral bilateral teleoperation control method based on LS-SVM (least square support vector machine) delay predication, which can be applied to a teleoperation system under time-varying delay. On the basis of a passivity wave variable method, a delay predication step and a wave integral step for the LS-SVM are added, the LS-SVM method is used for delay predication, predication delay which has small error with actual delay is obtained, the wave integral method can be used for enabling the communication step to have passivity, and thus instability caused to the teleoperation system due to time variable delay can be overcome. The invention relates to a control method in the teleoperation system under time-varying delay; at the main end, the force applied by a hand and the contact force fed back to the main end from a slave end together act on the main hand, speed and displacement are generated by the main hand, the speed signals of the main hand are transmitted to the slave end via a communication channel, and the signals serve as a control command to control movement of the slave hand.

The invention discloses a fixed time delay teleoperation control method based on a wave variable. A dynamical model and a time delay model of a master-slave terminal are established, a forward channel wave variable compensation term is designed, a backward channel wave variable compensation term is designed and finally an energy setting device is designed so that a problem of stability caused by time delay in teleoperation can be solved, and tracking performance and force feedback fidelity in the teleoperation process can be enhanced. Stability of a teleoperation system under the condition of fixed time delay can be greatly guaranteed so that the method has great position tracking performance and great force feedback fidelity. According to the teleoperation control method, stability of the teleoperation system under the condition of time delay can be guaranteed through a wave variable method, and position and force tracking performance of the time delay teleoperation system can also be enhanced.

This invention relates to class alternating frequency high torque flexible starting device, which can reduce current and improve starting torque to realize real flexible parking and motor short working low speed operation and braking status. This invention alters voltage frequency in the starting process and adopts the variable frequency method to realize slide lift flexible starting and adopts semi-wave variable frequency and adopts three-phase trigger impulse control circuit to generate three-phase modulation impulse signals.

The invention relates to a 14-bit width image compression hardware coder which can be used for reducing the storage space and transmission bandwidth required for recording and transmitting high bit width image with 8-14 bits and is developed based on a small wave image compression algorithm with low complexity. The coder comprises the modules as follows: an overall situation state machine controller, four data path gates, four data caches A, B, C and D, an image buffer, a first-stage small wave driver, a second-stage small wave driver, a third-stage small wave driver, a two-dimensional predicator, a two-dimensional small wave variable engine, a data transfer device, an optimization quantizer, a self-adaptive zero-course coder and an index Columbus coder. All the modules are organically combined for parallel processing, thereby realizing high-speed and high-bit width image compression with higher image quality. The real-time compression of a high-bit width camera image can remarkably reduce the image data amount, the storage volume and the requirements for transmission bandwidth.

The invention relates to a traveling wave protection fixed value setting method for a high-voltage direct-current transmission line. The method comprises the following steps that (1) a travelling wave protection function and an operation criterion mode are defined, and a polar wave fixed value and a floor mold wave fixed value are determined according to the operation criterion mode; (2) factors influencing the traveling wave fixed value are analyzed, and various simulation experiment conditions are set; (3) a simulation model is set up, simulation is carried out under two work conditions, all direct-current protection is closed in the simulation process, and polar wave data and floor mold wave data are extracted; (4) the polar wave data are processed, and the key failure information amount is extracted; (5) the polar wave fixed values under the two work conditions are calculated; (6) the minimum value of the floor mold wave variable quantity is extracted from the obtained floor mold wave data, and the floor mold wave fixed value is set by combining actual engineering parameters; (7) the obtained polar valve fixed values and floor mold wave fixed value are substituted into the simulation model, and rationality is verified. The formulating scheme of the simulation experiment conditions is analyzed in detail, the method is high in reliability and close degree to actual engineering, and therefore the method can be widely applied to high-voltage direct-current transmission traveling wave protection fixed value setting.

The invention relates to a high-precision digital acoustic variable density graduating method, which comprises: soaking an acoustic sonde of a variable density acoustic instrument in a graduated drum filled with water at a pressure of 2MP, or using a sine wave signal source of which the frequency is 20KHz to provide a signal without amplitude limit at a highest gain grade to a signal acquisition circuit of the instrument; fully resetting each correction coefficient of acoustic wave at each grade to be 1; acquiring several data with maximum values in a wave train, and calculating a mean value X1; using the formula X0 (40 percent)<n>Xn to calculate the correction coefficient; fading the density of the acoustic wave to 40 percent of the last grade in turn, and repeating the above steps for 8 grades; and storing the correction coefficient into a storage device of the variable density acoustic instrument. Therefore, the graduation precision of the instrument does not depend on precision of a high-performance resistance network; and the method reaches the precision through calculation and correction of software, improves test running speed of the instrument, and is favorable for large-scale production of the instrument.

The invention discloses a voltage-type three-level NPC (Neutral Point Clamped) converter direct power control method. A voltage-type three-level NPC (Neutral Point Clamped) converter is adopted. The method comprises the following steps: 1, ua, ub, uc, ia, ib and ic values are acquired, and instantaneous active power p and instantaneous reactive power q are calculated; 2, according to the ua, ub, and uc values, the located sector thetan is determined; 3, an AC / DC voltage ratio eta is calculated; 4, according to the eta value, a voltage ratio variable Seta is determined; 5, an active power deviation variable Sp and a reactive power deviation variable Sq are determined; 6, a reactive wave variable Srp is determined; 7, a specific vector adopted by a DPC strategy is determined; 8, switching states of VS1 to VS6 are selected to balance DC capacitor voltage; and 9, a switch device is controlled to enable the actual output power of the system to reach set requirements. The method can be applied to any AC / DC voltage ratio, and abnormal fluctuations of instantaneous reactive power are not caused.

A surface plasma polarization wave variable propagating width wave guide based on graphene comprises a silicon substrate and a silicon dioxide substrate which are overlapped. A step-shaped band protrusion is arranged on the silicon substrate, a step-shaped band groove matched with the step-shaped band protrusion is arranged on the silicon dioxide substrate, the step-shaped protrusion is inserted into the step-shaped band groove, the silicon dioxide substrate is provided with a graphene layer, one pole of a bias voltage source is positioned on the silicon substrate, and the other pole of the bias voltage source is positioned on the graphene. The propagating width of the surface plasma polarization wave variable propagating width wave guide based on graphene varies with the bias voltage through design of widths and the bias voltage in different areas of the silicon substrate. The surface plasma polarization wave variable propagating width wave guide based on graphene can be operated on a plurality of frequency points, is light in weight, convenient to process and easy to integrate, and has a good application prospect.

The invention discloses a four-way teleoperation bilateral control method based on time delay compensation. Based on a traditional four-way bilateral control method, by establishing a master-slave endkinetic model and additionally adopting a time delay compensation communication channel, the system stability is ensured, and the system transparency is improved substantially. To solve the problem that a traditional four-way bilateral control method has a destabilization phenomenon on the correspondence time delay condition, a correction wave variable method based on the passive theory is provided, so that the influence on the system transparency by wave reflection of a traditional wave variable is reduced, and the realistic degrees of position tracking performance and force feedback in theteleoperation process are ensured. The stability of a teleoperation system on the time delay condition can be ensured very well, and at the same time, the realistic degrees of the position tracking performance and the force feedback of the slave end are improved. The four-way teleoperation bilateral control method is easy to implement, and can be mainly used for bilateral control on the teleoperation system, and the stability and transparency of the teleoperation system are ensured.

The invention relates to a device generating random intermediate frequency output in a receiving frequency conversion system. The device comprises a second local oscillator circuit with continuously variable frequency. The minimum amount of a frequency step is 1Hz. The device also comprises a local oscillator segmentation filtering circuit and a wide bandwidth high out-of-band inhibition low pass filter. According to the device generating random intermediate frequency output in the receiving frequency conversion system, the range of intermediate frequency output is from 10MHz to 200MHz. Random intermediate frequency output of the microwave and millimeter wave variable frequency receiving frequency conversion system is realized, and greater flexibility is provided for subsequent signal analysis.

The invention discloses a wave variable displacement tracking and control method based on the local data of a slave. The purpose of the invention is to solve the technical problem that the wave variable can cause the tracking deviation of a master unit and a slave unit under the condition of delay. Aimed at a wave variable master-slave teleoperation system with delay, the method compensates the displacement deviation of the master unit and the slave unit in the master-slave teleoperation system caused by the change of the wave variable according to the local data of the slave unit, so that both the speed and displacement of the slave unit can accurately track the speed and displacement of the master unit, and thereby the stability and tracking performance of the master-slave teleoperation system are enhanced.

The invention discloses a four-channel teleoperation force feedback control method under hysteresis non-linearity limitation, and relates to the technical field of robot teleoperation system control.The four-channel teleoperation force feedback control method comprises the steps that a teleoperation system dynamic model under hysteresis non-linearity limitation is established; a master robot anda slave robot are selected and connected through a network to form a teleoperation system, and system parameters are measured separately; the mechanical arm position information of the master robot and the slave robot are measured in real time, and approximate force estimation is carried out on the applied force; an observed value of the force estimation is fed back into controller design; a four-channel wave variable communication channel under the time-varying delay is designed; and a four-channel bilateral controller is designed through the time domain passive control and an adaptive control method. According to the method, the passive property of the communication channel under the time-varying delay situation is guaranteed, very high tracking performance is achieved, the problem thatthe estimated capacity is limited and the estimation speed is slow of an existing force observer is solved, the demand on a force sensor is eliminated, and the hardware cost of the system is reduced.

The invention discloses a wave variable calculation method for a variable advantage factor double teleoperation. The method comprises: firstly, establishing master end and slave end kinetic models of the variable advantage factor double teleoperation; secondly, designing a to-be-transmitted master end variable; thirdly, selecting a wave variable and establishing a communication model; and finally, obtaining the wave variable. According to the method disclosed by the invention, location information of a plurality of master ends is fused, and wave variable conversion is carried out. A relatively small amount of wave variable information needs to be transmitted. Compared to a conventional method for transmitting location information of two master ends via respective transmission channels, the method disclosed by the invention only needs one channel to transmit the wave variable information. In addition, aimed at the time delay problem ubiquitous in the teleoperation, the passivity of the teleoperation can be ensured very well. According to the wave variable method adopted by the invention, energy is temporarily stored in a remote operating system through time delay, so that the passivity of the remote operating system can be ensured, and the remote operating system has stability.

The invention discloses a wave variable four-channel bilateral control method based on master-end force buffer. On the basis of the research on the synchronization performance of a bilateral teleoperation control system, a quantitative measurement function of force feedback of the synchronization of the bilateral control system in the condition of fixed time delay is given by the wave variable four-channel bilateral control method. In a wave variable four-channel bilateral control structure, a force buffer unit and a compensation unit are added to a master-end controller, so that the synchronous control over a master end and a slave end is realized, and the influence of a wave transformation method on the advanced effect of the master-end controller is eliminated. On the basis of synchronization indices provided by the wave variable four-channel bilateral control method, the master-slave synchronization analysis performed on the designed control system indicates that the designed control system has good synchronization performance.

The invention discloses a stability control method for a time-delay asymmetric double-teleoperation system. The method is characterized by, to begin with, establishing a model of the asymmetric double-teleoperation system; then, designing wave variables; and finally, establishing a time delay model. According to the method, speed and force information is converted into the wave variables and then, are transmitted; according to the passivity theory, passivity of channels under any fixed time delay condition can be ensured, and passivity of the double-teleoperation system under any fixed time delay condition can be ensured; and wave transform can be realized only by carrying out simple arithmetic operation on the speed and force information, and the method is easy to realize. Finally, the method can ensure the passivity of the channels under any fixed time delay condition; and master ends, a slave end and an environmental model are passive, so that passivity and stability of the whole system under any fixed time delay condition can be ensured.

The invention discloses a method for remote operation bilateral control by changing wave variables. Based on a traditional wave variable bilateral control method, a communication channel structure isimproved by establishing a master-slave dynamic model, and the transparency of a system is greatly improved while the system stability is ensured. Against the wave reflection phenomenon existing in the conventional wave variable bilateral control method, two parameters that can be independently selected according to different requirements are provided, the structure is simplified, the influence ofthe wave reflection on the transparency of a system is alleviated, and the position tracking performance and force feedback fidelity in the remote operation process are ensured. According to the method for remote operation bilateral control by changing the wave variables, the stability of a teleoperation system under the condition of delay can be ensured well, and the position tracking performance and the fidelity of force feedback at the slave end are improved. The method for remote operation bilateral control is easy to implement and apply and can mainly be used for bilateral control of theteleoperation system, and system stability and transparency are ensured.

The invention discloses a millimeter wave variable gain amplifier structure, and relates to the technical field of electronic circuit design, in particular to the technical field of radio frequency variable gain amplifier design suitable for a millimeter wave phased array system. The circuit comprises a first part of circuit formed by a common source transistor; A second partial circuit that generates a variable gain output signal; A third part circuit composed of an input matching network; And a fourth part of circuit of the output matching network. According to the invention, the purposes oflow cost, suitability for CMOS technology, high gain, large adjustment range, high precision and low phase shift are achieved.

The invention discloses an improved-wave-variable-based four-channel teleoperation multi-side control method. According to the method, the two-side control method is extended to multi-side control; and weight distribution coefficients of a master end and a slave end are designed to realize the multi-side cooperative working function of the system, so that the working efficiency of the system is improved. Besides, a master-slave-end dynamics model is established, a delay compensation communication channel is added, and an ideal transparency condition of the system is proposed, so that the system stability is ensured, the transparency of the system is improved substantially, and the multi-side immediacy sense of the operator is enhanced. In order to solve a problem of instability under the communication delay of the traditional four-channel control method, the invention puts forward a passive-theory-based improved wave variable method; and with two parameters selected independently basedon different needs, a negative effect on the system transparency by the wave reflection phenomenon in the traditional wave variable is reduced and the position tracking performance and force feedbackfidelity of the system during the multi-side teleoperation process are ensured.

The invention discloses a series resonance voltage-withstanding partial-discharge test method utilizing frequency modulation phase shift, and relates to alternating current voltage-withstanding and partial-discharge test of electrical equipment. According to the series resonance voltage-withstanding partial-discharge test method utilizing frequency modulation phase shift, a frequency modulation series resonance voltage-withstanding partial-discharge test system composed of a rectangular wave variable-frequency power source, a resonant electric reactor, a partial-discharge instrument and the like is utilized, excitation voltage frequency is down-regulated when a resonance voltage reaches a set value of the test voltage, the system deviates from the resonant state and produces phase shift, four burrs (namely interference signals) formed on a time base of the partial-discharge instrument when a variable-frequency power source switching tube is switched on and switched off are moved to second and fourth quadrants rightwards from positions distributed on two edges of + / - 90 degrees, the excitation voltage pulse width is increased to enable the resonance voltage to reach the set value of the test voltage again, and then windows can be opened at first and third quadrants for partial discharge test of tested products. By means of the series resonance voltage-withstanding partial-discharge test method, interference on the partial-discharge test, caused by variable-frequency power source switching pulses, is avoided, the fact that people doubt whether windowing or blanking eliminates the partial discharge of the tested products is avoided, and therefore the reliable and high-efficiency rectangular wave variable-frequency power source is used for the voltage-withstanding partial-discharge test of various kinds of electrical equipment.

The invention discloses a method for judging internal and external faults of a direct-current line area of a hybrid direct-current power transmission system. The method comprises the steps of 1 takinga time data window after a protection starting element is started, and calculating a fault component, a line-mode voltage fault component, a line-mode current fault component and a line-mode voltagereverse traveling wave therein; 2 calculating a sampling point ks and a minimum value of a reverse traveling wave change rate in two points after the sampling point ks, and recording the minimum valueas dub / dt_m<3>; 3 setting a threshold value th1, comparing the threshold value th1 with -dub / dt_m <3>, and judging whether the fault is a line external fault or not; 4 finding out a sampling point corresponding to a reverse traveling wave descending end moment caused by the fault first traveling wave through point-by-point comparison; 5 calculating a descending amplitude value A under the fault first traveling wave; 6 calculating a reverse traveling wave variable quantity S in the remaining data window; 7 calculating the ratio R of the reverse traveling wave variable quantity to the decreasing amplitude value under the fault first traveling wave; and 8 setting a threshold value th2, comparing the threshold value th2 with R, and judging whether the fault is a fault in the line area. The method is higher in sensitivity, and can distinguish high-resistance faults.

The invention aims to provide an adjustable width sinusoidal binary offset carrier modulation (AWSBOC (m, n, Rho)) method, comprising the processes of: first, determining a spreading code frequency fc, a subcarrier frequency fsc, a sine or cosine subcarrier modulation mode and a sinusoidal wave variable parameter Rho, and constructing sine or cosine phase subcarrier modulation waves in spreading code chip intervals; and second, utilizing a pseudorandom sequence to perform spread spectrum on navigation signals, then performing subcarrier modulation, and finally performing orthogonal branch carrier wave modulation on obtained signals. The signals generated in the method can flexibly adjust the main lobe and side lobe split degree of a signal power spectrum, thereby allowing the navigation signals to possess the characteristics of good code tracking performance, high anti-interference and anti-multipath capability, and great compatible capability with signals of other systems.

The invention relates to a high-power pseudo-spark switch tube for power electronic pulse conversion, belonging to the technical field of a gas power electronic switch device. The high-power pseudo-spark switch tube comprises a main electrode, a trigger electron gun, a hydrogen storage unit, a sealing tube body and an outer circuit, wherein the main electrode comprises a first anode and a second anode; the first anode and second anode are closed at the two ends, leave each other for certain distance and are coaxial hollow cylinders; the trigger electron gun comprises a tubular cathode, a tungsten heating wire, an outer tube and a trigger electrode, and is arranged below the main electrode while the muzzle of the electron gun is aligned with an electron injection hole of the second anode; titanium hydride powder is arranged in the hydrogen storage unit, and the heating wire is spirally wound on the surface; and the outer circuit comprises a main power supply and load thereof, a triggerpower supply and a voltage division resistor thereof, a heating wire power supply and an electronic switch. According to the invention, the on / off of the main electrode is realized through the pseudo-spark discharge between two anodes; and the high-power pseudo-spark switch tube has the advantages of high withstand voltage, large on current, high repeat switch frequency, low on voltage drop and the like, is easy to conduct by trigger, allows short circuit of an output end, and is suitable for being used as a main switch element in an indirect type constant-energy pulse chopped-wave variable-frequency speed control system.

The invention provides a water flow fluctuation generator and a use method thereof, and belongs to the technical field of water treatment. The generator comprises a constant-level water distribution system, a rectangular wave variable flow system and a sine wave-like variable flow system, wherein a base flow water outlet pipe, a rectangular wave water outlet pipe and a sine wave-like water outlet hose are connected to the lower part of a constant-level water distribution tank respectively; the base flow water outlet pipe is used for stable reference water flow for rectangular and sine wave-like outlet water; combined iron sheets are mounted on the panel of a porous disc at an equal interval, so that the effect of cyclic rectangular wave variable flow water discharge can be achieved during rotation; the sine wave-like water outlet hose is fixed to a rotary rod of the porous disc by a hanging rope, so that the height difference between the liquid level of the constant-level water distribution tank and the opening of the water outlet pipe is changed according to a sine curve along with time, and then sine wave-like variable flow outlet water is generated. According to the water flow fluctuation generator, the blank of experimental equipment and function detection in a study on a quantity adjusting tank is made up for and the needs of adjustment effect quantization function evaluation and structure optimization of the quantity adjusting tank can be met.

The invention relates to a radio-frequency amplifier intermodulation suppression level measurement method based on an X-parameter. The method comprises the step that the target X parameter of a radio-frequency amplifier is measured, wherein the target X parameter is a target parameter set; for the target X parameter, the scattered wave variable of the radio-frequency amplifier is acquired; the mapping relation among an incident wave variable, the scattered wave variable and signal power is constructed; and the intermodulation suppression level of the radio-frequency amplifier is acquired according to the mapping relation. According to the invention, the measurement method is simpler and more convenient that an intermodulation suppression level measurement method in the existing GJB151B-2013 in the aspects of experimental equipment and experimental steps.

The invention discloses an improved wave variable method in a bilateral remote operating system. The bilateral remote operating system comprises an operator, a main end, a communication link, a slaveend and an environment. In the communication link, an improved wave variable transformation is performed, an adjustable additional wave impedance coefficient is added during a transformation process,and a relationship among the improved wave variable, a position variable and a force variable is obtained. Through the improved wave variable method, under the condition of ensuring the stability of the bilateral remote operating system, operational performance of the system is improved, and a force / position tracking error is reduced.

The invention relates to a 14-bit width image compression hardware coder which can be used for reducing the storage space and transmission bandwidth required for recording and transmitting high bit width image with 8-14 bits and is developed based on a small wave image compression algorithm with low complexity. The coder comprises the modules as follows: an overall situation state machine controller, four data path gates, four data caches A, B, C and D, an image buffer, a first-stage small wave driver, a second-stage small wave driver, a third-stage small wave driver, a two-dimensional predicator, a two-dimensional small wave variable engine, a data transfer device, an optimization quantizer, a self-adaptive zero-course coder and an index Columbus coder. All the modules are organically combined for parallel processing, thereby realizing high-speed and high-bit width image compression with higher image quality. The real-time compression of a high-bit width camera image can remarkably reduce the image data amount, the storage volume and the requirements for transmission bandwidth.

The invention discloses a fixed time delay teleoperation control method based on a wave variable. A dynamical model and a time delay model of a master-slave terminal are established, a forward channel wave variable compensation term is designed, a backward channel wave variable compensation term is designed and finally an energy setting device is designed so that a problem of stability caused by time delay in teleoperation can be solved, and tracking performance and force feedback fidelity in the teleoperation process can be enhanced. Stability of a teleoperation system under the condition of fixed time delay can be greatly guaranteed so that the method has great position tracking performance and great force feedback fidelity. According to the teleoperation control method, stability of the teleoperation system under the condition of time delay can be guaranteed through a wave variable method, and position and force tracking performance of the time delay teleoperation system can also be enhanced.

The invention discloses a series resonance voltage-withstanding partial-discharge test method utilizing frequency modulation phase shift, and relates to alternating current voltage-withstanding and partial-discharge test of electrical equipment. According to the series resonance voltage-withstanding partial-discharge test method utilizing frequency modulation phase shift, a frequency modulation series resonance voltage-withstanding partial-discharge test system composed of a rectangular wave variable-frequency power source, a resonant electric reactor, a partial-discharge instrument and the like is utilized, excitation voltage frequency is down-regulated when a resonance voltage reaches a set value of the test voltage, the system deviates from the resonant state and produces phase shift, four burrs (namely interference signals) formed on a time base of the partial-discharge instrument when a variable-frequency power source switching tube is switched on and switched off are moved to second and fourth quadrants rightwards from positions distributed on two edges of + / - 90 degrees, the excitation voltage pulse width is increased to enable the resonance voltage to reach the set value of the test voltage again, and then windows can be opened at first and third quadrants for partial discharge test of tested products. By means of the series resonance voltage-withstanding partial-discharge test method, interference on the partial-discharge test, caused by variable-frequency power source switching pulses, is avoided, the fact that people doubt whether windowing or blanking eliminates the partial discharge of the tested products is avoided, and therefore the reliable and high-efficiency rectangular wave variable-frequency power source is used for the voltage-withstanding partial-discharge test of various kinds of electrical equipment.