Low-noise driving circuit for oscillatory wave high-voltage generator and control method

Abstract

The invention provides a low-noise driving circuit for an oscillatory wave high-voltage generator and a control method, and belongs to the field of high-voltage test equipment and power systems, and the low-noise driving circuit comprises an analog alternating-current voltage source module, a multi-magnetic-core coupling type isolation power supply module, a linear multi-level driving module and an IGBT unit which are connected in sequence; the analog alternating-current voltage source module is used for generating a high-power analog high-frequency alternating-current voltage signal and supplying power to the multi-magnetic-core coupling type isolation power supply module; a primary side coil of the multi-magnetic core coupling type isolation power supply module is powered by the analog alternating current voltage source module; the secondary side electricity taking coil is connected in series with the IGBT unit; the linear multi-level driving module comprises a rectifying circuit, a low-dropout linear voltage regulator, a gate driver and a push-pull amplifying circuit which are sequentially connected in series, and is used for supplying power to the IGBT unit and the optical signal conversion module and driving the IGBT unit to operate; the electromagnetic interference and noise generated by the IGBT high-voltage switch module are significantly reduced, and the detection sensitivity of the oscillatory wave partial discharge test system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-voltage test equipment and power systems, and in particular relates to a low-noise drive circuit and a control method for an oscillating wave high-voltage generator, aiming to reduce the influence of system noise on partial discharge detection sensitivity. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In the power system, the detection of partial discharge is an important means to evaluate the health status of cables and insulation equipment. The oscillation wave test system detects partial discharge signals by generating attenuated oscillation waves. In the oscillation wave voltage high-voltage generator, the high-voltage electronic discharge switch composed of IGBT series modules has the advantage of low on-resistance compared to the photo-controlled thyristor. However, in the process of oscillation wave formation, the IGBT drive circuit generally composed of a switching power supply will introduce greater electromagnetic interference (EMI) and noise, which will significantly affect the detection sensitivity of the partial discharge signal.

[0004] Although the current IGBT drive circuit can realize the basic control function of IGBT, it has limitations in noise suppression. Especially when multiple IGBTs are used in series, the switching power supply isolation power supply and drive system used is difficult to effectively suppress the switching noise, thus interfering with the accurate acquisition of partial discharge signals. Summary of the invention

[0005] In order to overcome the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a low-noise driving circuit and control method for an oscillating wave high-voltage generator, which significantly reduces the electromagnetic interference and noise generated by the IGBT high-voltage switch module by optimizing the circuit structure and driving strategy, thereby improving the detection sensitivity of the oscillating wave partial discharge test system.

[0006] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0007] A first aspect of the present invention provides a low noise driving circuit for an oscillating wave high voltage generator;

[0008] A low-noise driving circuit for an oscillating wave high-voltage generator comprises an analog AC voltage source module, a multi-core coupled isolation power supply module, a linear multi-level driving module and an IGBT unit connected in sequence;

[0009] The analog AC voltage source module is used to generate a high-power analog high-frequency AC voltage signal and supply power to the multi-core coupled isolation power supply module;

[0010] The multi-core coupled isolated power supply module comprises a primary side coil, a magnetic core and a secondary side power taking coil, wherein the primary side coil and the secondary side power taking coil are both wound on the magnetic core; the primary side coil is powered by an analog AC voltage source module; the secondary side power taking coil is connected in series with the IGBT unit;

[0011] The linear multi-level driving module comprises a rectifier circuit, a low voltage drop linear regulator, a gate driver and a push-pull amplifier circuit connected in series in sequence; it realizes power supply to the IGBT unit and drives the IGBT unit to operate;

[0012] The linear multi-level driving module is also connected to the optical signal conversion module to supply power to the optical signal conversion module. The optical signal conversion module is used to convert the optical control signal transmitted by the optical fiber into a voltage control signal as the input of the IGBT unit.

[0013] As a further technical solution, the analog AC voltage source module includes a microcontroller, a voltage amplification unit and a power amplification unit connected in series in sequence; the microcontroller outputs an analog high-frequency sinusoidal voltage signal with adjustable amplitude and frequency through a digital-to-analog conversion unit.

[0014] As a further technical solution, the voltage amplification unit includes a coupling capacitor, an operational amplifier and an adjustment resistor; one end of the coupling capacitor is connected to the microcontroller, and the other end is connected to a voltage output end of the operational amplifier, and the other voltage output end of the operational amplifier is grounded.

[0015] As a further technical solution, the power amplification unit includes a plurality of power amplification unit sub-units connected in parallel with each other; the power amplification unit sub-units include a first PNP-type transistor and a first NPN-type transistor connected in series with each other.

[0016] As a further technical solution, the optical signal conversion module is composed of a photoelectric coupler, and the photoelectric coupler includes a receiver and a Schmitt trigger connected in series.

[0017] As a further technical solution, the rectifier circuit includes a plurality of diodes and capacitors, wherein the diodes are arranged in two groups, each group of diodes has two rectifier diodes connected in series, and each group of diodes and capacitors are connected in parallel with each other.

[0018] As a further technical solution, the low-voltage dropout linear regulator includes a first low-voltage dropout linear regulator, a second low-voltage dropout linear regulator, a third low-voltage dropout linear regulator, and a fourth low-voltage dropout linear regulator; wherein one end of the first low-voltage dropout linear regulator is connected in series with the rectifier circuit, and the other end is connected to the second low-voltage dropout linear regulator, the third low-voltage dropout linear regulator, and the fourth low-voltage dropout linear regulator which are connected in parallel.

[0019] As a further technical solution, the input end of the gate driver is connected to the optical signal conversion module, receives the voltage control signal output by the optical signal conversion module, and inputs the electrical control signal into the push-pull amplifier circuit.

[0020] As a further technical solution, the push-pull amplifier circuit includes a second PNP transistor and a second NPN transistor connected in parallel.

[0021] A second aspect of the present invention provides a control method for a low-noise driving circuit for an oscillation wave high-voltage generator.

[0022] A control method for a low-noise driving circuit for an oscillating wave high-voltage generator, comprising:

[0023] An analog AC voltage source module is used to generate a high-frequency AC voltage signal and to supply power to a multi-core coupled isolation power supply module;

[0024] The primary side coils of the multi-core coupled isolated power supply module are connected in series to serve as the load of the simulated AC voltage source module, and the secondary side power supply coil provides isolated power to the IGBT unit.

[0025] An optical signal conversion module is used to convert the optical signal into a voltage control signal, which is input into a linear multi-level driving module. Based on the voltage control signal, a gate driver is used to output polarity voltages of different states to drive the IGBT unit to achieve low-noise oscillation wave partial discharge testing.

[0026] One or more of the above technical solutions have the following beneficial effects:

[0027] The circuit provided in the present invention completely uses analog devices, has no switching devices, and does not generate switching noise generated by the semiconductor switch turning on and off similar to the partial discharge signal waveform, effectively realizing the low-noise function of the oscillation wave high-voltage generator. It also effectively improves the sensitivity and accuracy of partial discharge detection; it is suitable for IGBTs of different specifications and different types of oscillation wave partial discharge test systems, and has a wide range of application prospects.

[0028] Advantages of additional aspects of the present invention will be given in part in the following description, and in part will become obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0030] Figure 1 It is a system composition diagram of a low-noise driving circuit for an oscillation wave high-voltage generator in the first embodiment of the present application.

[0031] Figure 2 It is a structural principle diagram of a low-noise driving circuit for an oscillation wave high-voltage generator in Example 1 of the present application.

[0032] Figure 3 This is a circuit schematic diagram of a high-power analog AC source in Example 1 of the present application.

[0033] Figure 4 It is a schematic diagram of the winding connection method of the multi-core coupled isolated power supply in the first embodiment of the present application.

[0034] Figure 5 It is a schematic diagram of the IGBT linear multi-level drive circuit in Example 1 of the present application.

[0035] In the figure, 1 is a microcontroller; 2 is a coupling capacitor; 3 is an operational amplifier; 4 is a first NPN transistor; 5 is a first PNP transistor; 6 is a primary side coil; 7 is a secondary side power taking coil; 8 is a magnetic core; 9 is a first low voltage difference linear regulator; 10 is a second low voltage difference linear regulator; 11 is a third low voltage difference linear regulator; 12 is a fourth low voltage difference linear regulator; 13 is a second PNP transistor; and 14 is a second NPN transistor. DETAILED DESCRIPTION

[0036] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0037] It should be noted that the terms used herein are for describing specific embodiments only and are not intended to be limiting of exemplary embodiments according to the present invention.

[0038] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0039] Embodiment 1

[0040] This embodiment discloses a low-noise driving circuit for an oscillating wave high-voltage generator;

[0041] like Figure 1 and Figure 2 As shown, a low-noise driving circuit for an oscillating wave high-voltage generator comprises an analog AC voltage source module, a multi-core coupled isolation power supply module, a linear multi-level driving module and an IGBT unit connected in sequence;

[0042] The analog AC voltage source module is used to generate a high-power analog high-frequency AC voltage signal and supply power to the multi-core coupled isolation power supply module;

[0043] Combination Figure 3 , the analog AC voltage source module is composed of a microcontroller (Microcontroller Unit, MCU) 1, a voltage amplifier unit, and a power amplifier unit. Among them, the MCU outputs an analog high-frequency sinusoidal voltage signal with adjustable amplitude and frequency through a digital-to-analog conversion unit, as the input of the voltage amplifier unit, one end of which needs to be grounded. Specifically, FPGA can be used as the MCU. The voltage amplifier unit is connected to the microcontroller 1 through a coupling capacitor 2, and the high-frequency sinusoidal AC voltage is connected. The voltage amplification function is realized with an operational amplifier 3 as a core device, one end of the operational amplifier 3 is connected to the microcontroller 1 through a coupling capacitor 2, one voltage input end of the operational amplifier 3 is connected in series with the coupling capacitor 2, and the other voltage input end is connected in series with a resistor R1 and grounded, and the operational amplifier 3 is also connected in parallel with a resistor R2. By adjusting the resistance values ​​of resistors R1 and R2, different amplification factors can be achieved for the voltage.

[0044] The power amplifier unit is composed of multiple groups of typical Class B complementary symmetrical power amplifier circuits connected in parallel, namely power sub-units. Each power amplifier sub-unit consists of a group of first NPN transistors 4 and first PNP transistors 5, with models NJW0281G and NJW0302G respectively. The number of parallel power sub-units can be adjusted as needed to adjust the output power. The power amplifier unit is supplied by a positive polarity DC power supply and a negative polarity DC power supply, wherein both the positive and negative polarity DC power supplies are linear power supplies, which can effectively reduce the system noise level. The output end of the power amplifier unit is connected to the primary side of the multi-core coupled isolation power supply module.

[0045] Combination Figure 4 The multi-core coupled isolation power supply module is composed of a primary coil 6, a magnetic core 8, and a secondary power supply coil 7. Both the primary coil 6 and the secondary power supply coil 7 are wound on the magnetic core 8 to realize the isolated power supply of the series IGBT unit. In the multi-core coupled isolation power supply module, the magnetic core 8 is made of manganese-zinc ferrite and has a ring-shaped closed structure. The turns ratio of the primary coil 6 and the secondary power supply coil 7 is 3:1. The primary coils 6 of multiple magnetic cores 8 are connected in series, and the coils formed after the series connection serve as the load of the simulated AC voltage source module. The secondary power supply coil 7 is connected to the linear multi-level drive module. The high-frequency AC voltage generated by the coil is rectified into a DC voltage by a rectifier circuit, and is used as the output voltage of the linear multi-level drive module to realize the isolated power supply for the IGBT unit.

[0046] Combination Figure 5, a linear multi-level drive module, including a rectifier circuit, a low dropout linear regulator (Low Dropout Regulator, LDO), a gate driver and a push-pull amplifier circuit connected in series in sequence; to realize the power supply to the IGBT unit. Among them, the rectifier circuit is a full-bridge full-wave rectification circuit, which serves as the output stage of the secondary side power taking coil to realize the rectification of the high-frequency AC voltage and power the LDO. Specifically, in this embodiment, the rectifier model is GBJ1010, and its rectifier circuit includes a plurality of diodes and capacitors, wherein two groups of diodes are arranged, each group of diodes has two rectifier diodes connected in series, and each group of diodes and capacitors are connected in parallel with each other. The output end of the rectifier circuit is connected to the low dropout linear regulator.

[0047] The low-dropout linear regulator (LDO) includes a first low-dropout linear regulator 9, a second low-dropout linear regulator 10, a third low-dropout linear regulator 11, and a fourth low-dropout linear regulator 12, which output +12V, +5V, +15V, and -8V voltages, respectively, wherein the LDO model with an output of +5V is L7812CV, the LDO model with an output of +5V is L7805CV, and the LDO models with outputs of +15V and -8V are L7815CV and L7908CV, respectively. Specifically, one end of the first low-dropout linear regulator is connected in series with the rectifier circuit, and the other end is connected to the second low-dropout linear regulator, the third low-dropout linear regulator, and the fourth low-dropout linear regulator connected in parallel, and the first low-dropout linear regulator 9 is also connected in parallel with a capacitor. The second low voltage drop linear regulator 10 is also connected to the optical signal conversion module to supply power to the optical signal conversion module. The output ends of the third low voltage drop linear regulator 11 and the fourth low voltage drop linear regulator 12 serve as forward and reverse bias voltage sources of the IGBT unit respectively.

[0048] The linear multi-level driving module is also connected to the optical signal conversion module to supply power to the optical signal conversion module. The optical signal conversion module is composed of a photoelectric coupler, which includes a receiver and a Schmitt trigger connected in series. In this embodiment, the photoelectric coupler model is HFBR2522Z, which is used to convert the optical control signal transmitted by the optical fiber into a voltage control signal and input it into the gate driver.

[0049] The gate driver is powered by dual power supplies, and the driving signal is a voltage control signal shaped and output by the optical signal conversion module, and its model is TD350E. When the control stage input voltage is low, the gate driver outputs a positive polarity voltage; when the control stage input voltage is high, the gate driver outputs a negative polarity voltage; and the above output results are used as the input of the push-pull amplifier circuit.

[0050] The input end of the gate driver is connected to the optical signal conversion module, receives the voltage control signal output by the optical signal conversion module, and inputs the electrical control signal into the push-pull amplifier circuit. The push-pull amplifier circuit includes a second PNP transistor 13 and a second NPN transistor 14 connected in parallel. The second PNP transistor 13 is of model MJE15030, and the second NPN transistor 14 is of model MJE15031. The bases of the second PNP transistor 13 and the second NPN transistor 14 are respectively connected to the output ends OUTH and OUTL of the gate driver, and the collectors are respectively connected to the output ends of the third low-voltage difference linear regulator 11 and the fourth low-voltage difference linear regulator 12. The emitters are also connected in series with resistors Rg, respectively, to achieve power amplification of the output signal of the gate driver, improve the ability to drive the IGBT unit, and achieve the purpose of enhancing the detection sensitivity of the oscillation wave high-voltage generator partial discharge test system.

[0051] Embodiment 2

[0052] This embodiment discloses a control method for a low-noise driving circuit for an oscillating wave high-voltage generator, including:

[0053] An analog AC voltage source module is used to generate a high-frequency AC voltage signal and to supply power to a multi-core coupled isolation power supply module;

[0054] The primary side coils of the multi-core coupled isolated power supply module are connected in series to serve as the load of the simulated AC voltage source module, and the secondary side power supply coil provides isolated power to the IGBT unit.

[0055] An optical signal conversion module is used to convert the optical signal into a voltage control signal, which is input into a linear multi-level driving module. Based on the voltage control signal, a gate driver is used to output polarity voltages of different states to drive the IGBT unit to achieve low-noise oscillation wave partial discharge testing.

[0056] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A low-noise driving circuit for an oscillating wave high-voltage generator, characterized in that: It includes an analog AC voltage source module, a multi-core coupled isolation power supply module, a linear multi-level drive module and an IGBT unit connected in sequence; The analog AC voltage source module is used to generate a high-power analog high-frequency AC voltage signal and supply power to the multi-core coupled isolation power supply module; The multi-core coupled isolated power supply module comprises a primary side coil, a magnetic core and a secondary side power taking coil, wherein the primary side coil and the secondary side power taking coil are both wound on the magnetic core; the primary side coil is powered by an analog AC voltage source module; the secondary side power taking coil is connected in series with the IGBT unit; The linear multi-level driving module includes a rectifier circuit, a low voltage drop linear regulator, a gate driver and a push-pull amplifier circuit connected in series in sequence, so as to realize power supply to the IGBT unit and drive the IGBT unit to operate; The linear multi-level driving module is also connected to the optical signal conversion module to supply power to the optical signal conversion module. The optical signal conversion module is used to convert the optical control signal transmitted by the optical fiber into a voltage control signal as the input of the IGBT unit.

2. A low-noise driving circuit for an oscillating wave high-voltage generator as claimed in claim 1, characterized in that: The analog AC voltage source module comprises a microcontroller, a voltage amplification unit and a power amplification unit which are connected in series in sequence; the microcontroller outputs an analog high-frequency sinusoidal voltage signal with adjustable amplitude and frequency through a digital-to-analog conversion unit.

3. A low noise driving circuit for an oscillating wave high voltage generator as claimed in claim 2, characterized in that: The voltage amplification unit comprises a coupling capacitor, an operational amplifier and an adjustment resistor; one end of the coupling capacitor is connected to the microcontroller, and the other end is connected to a voltage output end of the operational amplifier, and the other voltage output end of the operational amplifier is grounded.

4. A low noise driving circuit for an oscillating wave high voltage generator as claimed in claim 2, characterized in that: The power amplification unit comprises a plurality of power amplification unit sub-units connected in parallel with each other; the power amplification unit sub-units comprise a first PNP type transistor and a first NPN type transistor connected in series with each other.

5. A low noise driving circuit for an oscillating wave high voltage generator as claimed in claim 1, characterized in that: The optical signal conversion module is composed of a photoelectric coupler, and the photoelectric coupler includes a receiver and a Schmitt trigger connected in series.

6. A low noise driving circuit for an oscillating wave high voltage generator as claimed in claim 1, characterized in that: The rectifier circuit includes a plurality of diodes and capacitors, wherein the diodes are arranged in two groups, each group of diodes includes two rectifier diodes connected in series, and each group of diodes and capacitors are connected in parallel with each other.

7. A low noise driving circuit for an oscillating wave high voltage generator as claimed in claim 1, characterized in that: The low-voltage dropout linear regulator includes a first low-voltage dropout linear regulator, a second low-voltage dropout linear regulator, a third low-voltage dropout linear regulator, and a fourth low-voltage dropout linear regulator; wherein one end of the first low-voltage dropout linear regulator is connected in series with the rectifier circuit, and the other end is connected to the second low-voltage dropout linear regulator, the third low-voltage dropout linear regulator, and the fourth low-voltage dropout linear regulator which are connected in parallel.

8. A low noise driving circuit for an oscillating wave high voltage generator as claimed in claim 1, characterized in that: The input end of the gate driver is connected to the optical signal conversion module, receives the voltage control signal output by the optical signal conversion module, and inputs the voltage control signal into the push-pull amplifier circuit.

9. A low noise driving circuit for an oscillating wave high voltage generator as claimed in claim 1, characterized in that: The push-pull amplifier circuit comprises a second PNP transistor and a second NPN transistor connected in parallel.

10. A control method for a low-noise driving circuit for an oscillating wave high-voltage generator according to any one of claims 1 to 9, characterized in that: include: An analog AC voltage source module is used to generate a high-frequency AC voltage signal and to supply power to a multi-core coupled isolation power supply module; The primary side coils of the multi-core coupled isolated power supply module are connected in series to serve as the load of the simulated AC voltage source module, and the secondary side power supply coil provides isolated power to the IGBT unit. An optical signal conversion module is used to convert the optical signal into a voltage control signal, which is input into a linear multi-level driving module. Based on the voltage control signal, a gate driver is used to output polarity voltages of different states to drive the IGBT unit to achieve low-noise oscillation wave partial discharge testing.

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