A high-voltage square wave pulse power supply with precise and continuous frequency modulation

Abstract

The present invention discloses a high-voltage square wave pulse power supply with precise and continuous frequency modulation, which is composed of an air switch, a voltage regulator, an industrial frequency transformer, a rectifier filter, an IGBT full-bridge inverter unit, a square wave pulse transformer, a human-machine interface, and an IGBT drive unit; the IGBT full-bridge inverter unit is composed of four field effect tubes V1-V4; the IGBT drive unit is composed of a programmable controller, a dual-channel dead zone generation circuit, and four drivers. The programmable controller outputs a square wave pulse signal with a continuous and precise adjustable frequency, and generates two complementary drive signals with dead zones through a dead zone generation chip. The complementary drive signals drive the inverter bridge composed of high-power IGBTs through an isolation drive chip, thereby realizing automatic and continuous frequency adjustment in a wide range of 1kHz to 20kHz or stable output at a fixed frequency.

Description

Technical Field

[0001] The invention relates to the technical field of power supply, in particular to a high-voltage square wave pulse power supply with precise and continuous frequency modulation. Background Art

[0002] The high-voltage square wave pulse power supply regulates the grid voltage through the voltage regulator, isolates and boosts the voltage through the transformer, rectifies, and filters it into a DC voltage. Then, four high-power IGBTs form an inverter full bridge to invert the DC voltage into a square wave pulse voltage, which is then boosted to the required voltage value through a square wave pulse transformer. The high-voltage square wave pulse power supply is mainly used for the electrical life assessment of the insulation structure of variable frequency motors used in the fields of motor traction, wind power generation, and new energy vehicles. During the test, the high-voltage square wave pulse power supply is boosted from zero by the voltage regulator, and the voltage regulation is stopped after the voltage required for the test is reached through rectification, inversion, and boosting. The voltage regulation position remains unchanged until the sample is destroyed or the test time is reached. The required test voltage peak-to-peak value and frequency are different according to the type of the sample. However, the current high-voltage square wave pulse power supply has the problem that it is difficult to automatically adjust the frequency over a wide range and has poor stability, which affects the experimental results of the electrical life assessment. Summary of the invention

[0003] The present invention aims to solve the problem that the existing high-voltage square wave pulse power supply is difficult to automatically adjust the frequency in a wide range and has poor stability, and provides a high-voltage square wave pulse power supply with accurate and continuous frequency modulation.

[0004] To solve the above problems, the present invention is achieved through the following technical solutions:

[0005] A high-voltage square wave pulse power supply with precise and continuous frequency modulation, which is composed of a circuit breaker, a voltage regulator, a power frequency transformer, a rectifier filter, an IGBT full-bridge inverter unit, a square wave pulse transformer, a human-machine interface, and an IGBT drive unit; the IGBT full-bridge inverter unit is composed of 4 field effect transistors V1-V4; the IGBT drive unit is composed of a programmable controller, a dual-channel dead zone generation circuit and 4 drivers;

[0006] The external power supply is connected to the input side of the voltage regulator via the circuit breaker, the output side of the voltage regulator is connected to the input side of the power frequency transformer, the output side of the power frequency transformer is connected to the input positive terminal and the input negative terminal of the rectifier filter; the output positive terminal of the rectifier filter is connected to the drain of the field effect tube V1 and the drain of the field effect tube V3, the output negative terminal of the rectifier filter is connected to the source of the field effect tube V4 and the source of the field effect tube V2; the source of the field effect tube V3 and the drain of the field effect tube V2 are commonly connected to the positive terminal of the input side of the square wave pulse transformer, the source of the field effect tube V1 and the drain of the field effect tube V4 are commonly connected to the negative terminal of the input side of the square wave pulse transformer; the output side of the square wave pulse transformer is The sample to be tested is connected; the human-machine interface is connected to the programmable controller, the voltage regulation control end of the programmable controller is connected to the control end of the voltage regulator, and the clock control end of the programmable controller is connected to the input end of the dual-path dead zone generating circuit; the Q' output end of the dual-path dead zone generating circuit is connected to the input end of the first driver and the second driver, and the Q output end of the dual-path dead zone generating circuit is connected to the input end of the third driver and the fourth driver; the input end of the first driver is connected to the gate of the field effect tube V1, the input end of the second driver is connected to the gate of the field effect tube V2, the input end of the third driver is connected to the gate of the field effect tube V3, and the input end of the fourth driver is connected to the gate of the field effect tube V4.

[0007] In the above scheme, the dual-path dead zone generating circuit is composed of 6 XOR gates U1A-U1D, U2A-U2B, resistors R1-R2 and capacitors C1-C2; the two input terminals of XOR gate U1A and one input terminal of XOR gate U2A are connected to form the input terminal of the dual-path dead zone generating circuit; the output terminal of XOR gate U1A is connected to one terminal of resistor R1, two input terminals of XOR gate U1B, and one input terminal of XOR gate U2B; the other terminal of resistor R1 is connected to one terminal of capacitor C1, two terminals of XOR gate U2C, and one input terminal of capacitor C1. The output end of the XOR gate U2C is connected to the other input end of the XOR gate U2A; the output end of the XOR gate U2A forms the Q' output end of the dual-path dead zone generating circuit; the output end of the XOR gate U1B is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the capacitor C2, and the two input ends of the XOR gate U1D; the output end of the XOR gate U1D is connected to the other input end of the XOR gate U2B; the output end of the XOR gate U2B forms the Q output end of the dual-path dead zone generating circuit; the other ends of the capacitors C1 and C2 are grounded.

[0008] Compared with the prior art, the present invention outputs a square wave pulse signal with a continuously and accurately adjustable frequency through a programmable controller, and generates two complementary drive signals with dead zones through a dead zone generating chip. The complementary drive signals drive an inverter bridge composed of high-power IGBTs through an isolation drive chip, thereby achieving automatic and continuous adjustment of the frequency within a wide range of 1kHz to 20kHz or stable output at a certain fixed frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 The schematic diagram is a principle block diagram of a high-voltage square wave pulse power supply with precise and continuous frequency modulation. DETAILED DESCRIPTION

[0010] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific examples.

[0011] See also Figure 1 , a precise and continuous frequency modulated high-voltage square wave pulse power supply, consists of a circuit breaker, a voltage regulator, a power frequency transformer, a rectifier filter, an IGBT full-bridge inverter unit, a square wave pulse transformer, a human-machine interface, and an IGBT drive unit. The IGBT full-bridge inverter unit consists of four field effect tubes V1-V4. The IGBT drive unit consists of a programmable controller, a dual-channel dead zone generation circuit, and four drivers.

[0012] The dual-path dead zone generating circuit is composed of 6 XOR gates U1A-U1D, U2A-U2B, resistors R1-R2 and capacitors C1-C2. The two input terminals of XOR gate U1A and one of the input terminals of XOR gate U2A are connected to form the input terminal of the dual-path dead zone generating circuit. The output terminal of XOR gate U1A is connected to one end of resistor R1, two input terminals of XOR gate U1B, and one input terminal of XOR gate U2B. The other end of resistor R1 is connected to one end of capacitor C1 and two input terminals of XOR gate U2C. The output terminal of XOR gate U2C is connected to the other input terminal of XOR gate U2A. The output terminal of XOR gate U2A forms the Q' output terminal of the dual-path dead zone generating circuit. The output end of the XOR gate U1B is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to one end of the capacitor C2 and the two input ends of the XOR gate U1D. The output end of the XOR gate U1D is connected to the other input end of the XOR gate U2B. The output end of the XOR gate U2B forms the Q output end of the dual-path dead zone generating circuit. The other ends of the capacitors C1 and C2 are grounded.

[0013] The external power supply is connected to the input side of the voltage regulator via the circuit breaker, the output side of the voltage regulator is connected to the input side of the power frequency transformer, and the output side of the power frequency transformer is connected to the positive input terminal and the negative input terminal of the rectifier filter. The positive output terminal of the rectifier filter is connected to the drain of the field effect tube V1 and the drain of the field effect tube V3, and the negative output terminal of the rectifier filter is connected to the source of the field effect tube V4 and the source of the field effect tube V2. The source of the field effect tube V3 and the drain of the field effect tube V2 are connected to the positive terminal of the input side of the square wave pulse transformer, and the source of the field effect tube V1 and the drain of the field effect tube V4 are connected to the negative terminal of the input side of the square wave pulse transformer. The output side of the square wave pulse transformer is connected to the sample to be tested. The human-machine interface is connected to the programmable controller, the voltage regulation control terminal of the programmable controller is connected to the control terminal of the voltage regulator, and the clock control terminal of the programmable controller is connected to the input terminal of the dual-channel dead zone generation circuit. The Q' output end of the dual-path dead zone generating circuit is connected to the input end of the first driver and the second driver, and the Q output end of the dual-path dead zone generating circuit is connected to the input end of the third driver and the fourth driver. The input end of the first driver is connected to the gate of the field effect tube V1, the input end of the second driver is connected to the gate of the field effect tube V2, the input end of the third driver is connected to the gate of the field effect tube V3, and the input end of the fourth driver is connected to the gate of the field effect tube V4.

[0014] The IGBT drive unit is composed of a high-speed pulse generator of a programmable controller that outputs a corresponding square wave pulse train according to the frequency value input by the human-machine interface. The square wave pulse generates two inverted pulse drive signals with dead zones through a dual-channel dead zone circuit. The two inverted pulse drive signals with dead zones then drive the four IGBTs of the IGBT full-bridge inverter unit through four drivers, thereby inverting the DC voltage on the bridge into a square wave pulse voltage, which is then boosted to the required voltage value through a high-power high-voltage square wave pulse transformer. The square wave voltage frequency of the high-voltage square wave pulse power supply is required to be continuously adjustable from 1kHz to 20kHz, and it is required to have a rising edge as fast as possible. When outputting a certain frequency, it is required to be stable and reliable. The programmable controller uses a built-in crystal oscillator to generate a reference clock. The pulse output end can generate square wave pulses at a precise single frequency point, and can easily realize the automatic continuous frequency sweep function at 1kHz to 20kHz, solving the problem that the oscillation pulse signal generator composed of the traditional voltage regulation chip changes with the temperature drift of the external RC, and the inconvenience of automatic frequency sweeping.

[0015] The performance of the present invention is analyzed by experiments below:

[0016] 1. Take 20 coil samples of the same capacity and withstand voltage level and divide them into 4 groups: A, B, C, and D. The rated test voltage of each group is set to 10.00 kV, and the test time is 100 h. The test frequency of group A and group B samples is 1 kHz, and the test frequency of group C and group D samples is 20 kHz. The test device of group A and group C is used to generate complementary drive signals by SG3525 for testing, and the power supply device of group B and group D is used for testing. The tests are started simultaneously when the other conditions are the same.

[0017] 2. Group A uses the test device that generates complementary drive signals from SG3525 to conduct the test. When the test starts, the system automatically boosts the voltage to the rated voltage of 10kV. The 20kΩ potentiometer knob is manually adjusted to change the frequency signal generated by SG3525 to 1kHz. The actual display value of the oscilloscope fluctuates between 1kHz and 1.02kHz, and its resolution is visually estimated to be about 0.02kHz. The frequency is recorded every 5 hours. After the 100-hour test, the statistical frequency value fluctuation range is 0.98kHz to 1.04kHz.

[0018] 3. Group C uses the test device that generates complementary drive signals from SG3525 to conduct the test. When the test starts, the system automatically boosts the voltage to the rated voltage of 10kV. The 20kΩ potentiometer knob is manually adjusted to change the frequency signal generated by SG3525 to 20kHz. The actual displayed value fluctuates between 19.99kHz and 20.03kHz, and its resolution is visually estimated to be about 0.02kHz. The frequency is recorded every 5 hours, and after the 100-hour test, the statistical frequency value fluctuation range is 19.95kHz to 20.12kHz.

[0019] 4. Group B uses the test device of the present invention to conduct the test. When the test is started, the system automatically boosts the voltage to the rated voltage of 10kV. 1kHz is manually input on the screen, and the actual display value of the oscilloscope is 1.00kHz, without fluctuation. The frequency is recorded every 5 hours. After the 100-hour test, the statistical frequency value fluctuation range is 1.00kHz, without fluctuation.

[0020] 5. Group D was tested using the test device of the present invention. When the test was started, the system automatically boosted the voltage to the rated voltage of 10 kV. 20 kHz was manually input on the screen, and the actual display value of the oscilloscope was 20.00 kHz, without fluctuation. The frequency was recorded every 5 hours. After the 100-hour test, the statistical frequency value fluctuation range was 20.00 kHz to 20.01 kHz.

[0021] After monitoring and analysis, the test device using the traditional SG3525 to generate complementary drive signals has a large influence on the temperature drift of the adjustment device resistor and capacitor, and the value of the adjustment resistor will affect the frequency adjustment range and resolution. The square wave pulse signal output by the programmable controller of the present invention can not only be arbitrarily set within a wide range, but also output accurately, and the output frequency is stable and reliable.

[0022] The present invention is to develop a high-voltage square wave pulse power supply with wide-range precise frequency modulation, which has the characteristics of continuous adjustable frequency within a wide frequency range and stable output frequency. Its output frequency is continuously adjustable within the range of 1kHz to 20kHz, and the accuracy and stability are within 0.1%.

[0023] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention, and therefore the present invention is not limited to the above specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. A high-voltage square wave pulse power supply with precise and continuous frequency modulation, characterized in that: It consists of a circuit breaker, a voltage regulator, a power frequency transformer, a rectifier filter, an IGBT full-bridge inverter unit, a square wave pulse transformer, a human-machine interface, and an IGBT drive unit. The IGBT full-bridge inverter unit is composed of four field effect tubes V1-V4; the IGBT drive unit is composed of a programmable controller, a dual-channel dead zone generation circuit and four drivers; The dual-path dead zone generating circuit is composed of 6 XOR gates U1A-U1D, U2A-U2B, resistors R1-R2 and capacitors C1-C2; two input ends of XOR gate U1A and one input end of XOR gate U2A are connected to form the input end of the dual-path dead zone generating circuit; the output end of XOR gate U1A is connected to one end of resistor R1, two input ends of XOR gate U1B, and one input end of XOR gate U2B; the other end of resistor R1 is connected to one end of capacitor C1 and two input ends of XOR gate U2C; the output end of XOR gate U2C is connected to the output end of XOR gate U2A another input terminal; the output terminal of the XOR gate U2A forms the Q' output terminal of the dual-path dead zone generating circuit; the output terminal of the XOR gate U1B is connected to one end of the resistor R2, the other end of the resistor R2 is connected to one end of the capacitor C2, and the two input terminals of the XOR gate U1D; the output terminal of the XOR gate U1D is connected to the other input terminal of the XOR gate U2B; the output terminal of the XOR gate U2B forms the Q output terminal of the dual-path dead zone generating circuit; the other ends of the capacitors C1 and C2 are grounded; The external power supply is connected to the input side of the voltage regulator via the circuit breaker, the output side of the voltage regulator is connected to the input side of the power frequency transformer, and the output side of the power frequency transformer is connected to the input positive terminal and the input negative terminal of the rectifier filter; the output positive terminal of the rectifier filter is connected to the drain of the field effect tube V1 and the drain of the field effect tube V3, and the output negative terminal of the rectifier filter is connected to the source of the field effect tube V4 and the source of the field effect tube V2; The source of the field effect tube V3 and the drain of the field effect tube V2 are connected to the positive terminal of the input side of the square wave pulse transformer, and the source of the field effect tube V1 and the drain of the field effect tube V4 are connected to the negative terminal of the input side of the square wave pulse transformer; the output side of the square wave pulse transformer is connected to the sample to be tested; The human-machine interface is connected to the programmable controller, the voltage regulation control end of the programmable controller is connected to the control end of the voltage regulator, and the clock control end of the programmable controller is connected to the input end of the dual-path dead zone generating circuit; the Q' output end of the dual-path dead zone generating circuit is connected to the input end of the first driver and the second driver, and the Q output end of the dual-path dead zone generating circuit is connected to the input end of the third driver and the fourth driver; the input end of the first driver is connected to the gate of the field effect tube V1, the input end of the second driver is connected to the gate of the field effect tube V2, the input end of the third driver is connected to the gate of the field effect tube V3, and the input end of the fourth driver is connected to the gate of the field effect tube V4.

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