Interference generating device and method for simulating influence of IGBT on bradytelegraphy detection

Abstract

The present application belongs to the technical field of partial discharge detection, and particularly relates to an interference generating device and method for simulating the influence of IGBT on partial discharge detection. In view of the deficiency in the prior art that there is no device specially used for studying the influence of electromagnetic interference generated by the high-frequency switching process of IGBT on the partial discharge detection of flexible HVDC converter transformers, the present application adopts the following technical scheme: the interference generating device for simulating the influence of IGBT on partial discharge detection in a converter transformer comprises: an IGBT module for generating a switching frequency interference signal of IGBT; a partial discharge defect module for simulating a mixed signal of a partial discharge signal and a white noise signal; a filtering module for filtering the simulated signal formed by superposition; and a high-frequency sensor for collecting and processing the filtered signal to obtain an analog measurement value of partial discharge. The present application has the beneficial effects of: constructing a brand-new interference generating device; and simulating the actual working condition of the IGBT of a converter transformer through the on-off of IGBT, which is more accurate.

Description

Technical Field

[0001] This invention belongs to the field of partial discharge detection technology, specifically relating to an interference generator that simulates the influence of IGBTs on partial discharge detection. Background Technology

[0002] Electromagnetic interference (EMI) generated by insulated-gate bipolar transistors (IGBTs) during high-frequency switching is a key challenge in the design of power electronic devices. The high-frequency interference of IGBTs primarily stems from their extremely high voltage and current change rates (dv / dt and di / dt). These rapid transitions generate strong conducted and radiated interference through parasitic parameters such as stray inductance and capacitance, with a spectrum extending from low frequencies to hundreds of MHz or even GHz. In flexible DC transmission systems, the flexible DC harmonic interference generated by IGBTs during high-frequency switching affects the accuracy of partial discharge detection.

[0003] Various effective methods exist to suppress noise interference generated by partial discharge detection in AC transformers and traditional DC converter transformers, such as signal filtering using filters, signal enhancement with time-domain analysis to identify and distinguish signals from noise, wavelet transform, and adaptive filtering algorithms. However, the harmonic interference level in flexible DC transmission systems differs significantly from that in traditional DC transmission systems, and the methods used in AC systems are ineffective in suppressing harmonics in flexible DC transmission systems. Furthermore, existing research has not investigated the impact of electromagnetic interference generated by IGBTs on partial discharge detection.

[0004] Therefore, for the noise reduction process of partial discharge detection in large-capacity flexible DC transmission converter transformers, a signal generating device is needed to generate a large number of high-order harmonics, pulsations and white noise interferences to simulate the partial discharge defect signal superimposed with IGB electromagnetic interference. An interference suppression algorithm is introduced to capture interference characteristic parameters that are different from transformer partial discharge, so as to improve the accuracy of converter transformer partial discharge detection. Summary of the Invention

[0005] This invention addresses the deficiency in the prior art of lacking a dedicated device for studying the impact of electromagnetic interference generated during the high-frequency switching process of IGBTs on the partial discharge detection of flexible DC converter transformers. It provides an interference generation device and method for simulating the impact of IGBTs on partial discharge detection in converter transformers.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer, the interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer comprising: The IGBT module generates interference signals at the switching frequency of the IGBTs in the multilevel converter transformer. The partial discharge defect module simulates and generates a mixed signal of partial discharge signal and white noise signal; The filtering module filters the analog signal formed by the superposition of switching frequency interference signals and mixed signals; Coupling capacitor; Detection impedance; The IGBT module includes a rectifier circuit, an IGBT inverter circuit, a waveform generation circuit, a microcontroller, and a high-frequency transformer. The three-phase input is rectified and outputs a DC signal to the IGBT inverter circuit as the bus power supply. The microcontroller controls the waveform generation circuit to generate a periodic waveform as the signal to drive the IGBT inverter circuit. The signal generated by the IGBT inverter circuit is boosted by the high-frequency transformer.

[0007] As an improvement, the IGBT module also includes an adjustable power load for adjusting the IGBT output power, which is connected to the output of the high-frequency transformer.

[0008] As an improvement, the frequency range of the signal driving the IGBT inverter circuit is from tens of Hz to tens of kHz.

[0009] As an improvement, the filtering module includes a variable frequency filter.

[0010] As an improvement, the filter module adopts an RLC series circuit.

[0011] As an improvement, the values ​​of at least one of the resistors, inductors, and capacitors connected in the RLC series circuit are adjustable.

[0012] As an improvement, the RLC series circuit includes a digital potentiometer; and / or, An RLC series circuit includes at least two inductors connected in parallel and multiple relays that switch each inductor on and off; and / or An RLC series circuit includes at least two capacitors connected in parallel and multiple relays that switch each capacitor on and off.

[0013] As an improvement, a three-phase bridge rectifier circuit is adopted.

[0014] As an improvement, the three-phase bridge rectifier circuit includes four diodes and four thyristors. The four signals of the four thyristors VS1, VS2, VS3 and VS4 control the on and off of the four diodes respectively. VS1 and VS4 are one group, and VS2 and VS3 are another group. The two control signals in each group are the same, and the signals between the two groups are out of phase, and dead time is taken into account.

[0015] An interference generation method simulating the effect of IGBTs on partial discharge detection in a converter transformer is applied to the aforementioned interference generation device simulating the effect of IGBTs on partial discharge detection in a converter transformer. The interference generation method simulating the effect of IGBTs on partial discharge detection in a converter transformer includes: The switching frequency interference signal of the IGBT in the multilevel converter is generated by the IGBT module. A mixed signal of partial discharge signal and white noise signal is generated by simulating the partial discharge defect module; The filtering module filters the analog signal formed by the superposition of switching frequency interference signal and mixed signal. The signal at the detection impedance is collected to obtain the simulated measurement value of partial discharge.

[0016] This invention discloses an interference generation device for simulating the influence of IGBTs on partial discharge detection in a converter transformer. The device comprises an IGBT module, a partial discharge defect module, a filtering module, and a high-frequency sensor. The IGBT module controls the IGBT's on / off state via a high-frequency switching signal and outputs a signal simulating the switching frequency signal of the IGBT in a multi-level converter transformer. The partial discharge defect module simulates a mixed signal of partial discharge and white noise. The filtering module filters the simulated signal obtained by superimposing the mixed signal and the IGBT interference signal. A coupling capacitor and a detection impedance form a signal extraction circuit. The partial discharge instrument acquires the signal at the detection impedance to obtain the simulated measurement value of the partial discharge. This invention constructs a novel interference generation device. By simulating the actual operating conditions of the IGBTs in the converter transformer through the on / off switching of the IGBTs, it achieves greater accuracy than simply outputting a simulated waveform. Furthermore, the IGBT output power is adjustable to simulate the harmonic conditions of the IGBTs at different power levels. The unique multi-capacitor selective access structure of the high-frequency sensor can adapt to a wide range of IGBT interference signals, ensuring measurement accuracy. Attached Figure Description

[0017] Figure 1 This is a control principle diagram of the interference generation device for the influence of IGBT on partial discharge detection in a simulated converter transformer according to an embodiment of the present invention.

[0018] Figure 2 This is a circuit topology diagram of an interference generation device for the influence of IGBTs on partial discharge detection in a simulated converter transformer according to an embodiment of the present invention.

[0019] Figure 3 This is an equivalent circuit diagram of the high-frequency sensor of the interference generation device for the influence of IGBT on partial discharge detection in the simulated converter transformer of this invention.

[0020] Figure 4 This is a flowchart of an interference generation method for the influence of IGBTs on partial discharge detection in a simulated converter transformer according to an embodiment of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be explained and described below. However, the following embodiments are only preferred embodiments of the present invention and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present invention.

[0022] See Figures 1 to 4 The present invention provides an interference generating device for simulating the effect of IGBTs on partial discharge detection in a converter transformer. The device includes: The IGBT module generates interference signals at the switching frequency of the IGBTs in the multilevel converter transformer. The partial discharge defect module simulates and generates a mixed signal of partial discharge signal and white noise signal; The filtering module filters the analog signal formed by the superposition of switching frequency interference signals and mixed signals; Coupling capacitor; Detection impedance; The IGBT module includes a rectifier circuit, an IGBT inverter circuit, a waveform generation circuit, a microcontroller, and a high-frequency transformer. The three-phase input is rectified and outputs a DC signal to the IGBT inverter circuit as the bus power supply. The microcontroller controls the waveform generation circuit to generate a periodic waveform as the signal to drive the IGBT inverter circuit. The signal generated by the IGBT inverter circuit is boosted by the high-frequency transformer.

[0023] This invention discloses an interference generator for simulating the influence of IGBTs on partial discharge detection in a converter transformer. The device comprises an IGBT module, a partial discharge defect module, a filter module, and a high-frequency sensor. The IGBT module controls the IGBT's on / off state via a high-frequency switching signal and outputs a signal simulating the switching frequency signal of the IGBT in a multi-level converter transformer. The partial discharge defect module simulates a mixed signal of partial discharge and white noise. The filter module filters the simulated signal obtained by superimposing the mixed signal and the IGBT interference signal. A coupling capacitor and a detection impedance form a signal extraction circuit. The partial discharge meter acquires the signal at the detection impedance to obtain a simulated measurement value of the partial discharge. This invention constructs a novel interference generator. By simulating the actual operating conditions of the IGBTs in the converter transformer through the on / off switching of the IGBTs, it achieves greater accuracy compared to simply outputting a simulated waveform.

[0024] Example 1 See Figures 1 to 4 The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to Embodiment 1 of the present invention includes: The IGBT module generates interference signals at the switching frequency of the IGBTs in the multilevel converter transformer. The partial discharge defect module simulates and generates a mixed signal of partial discharge signal and white noise signal; The filtering module filters the analog signal formed by the superposition of switching frequency interference signals and mixed signals; A high-frequency sensor collects and processes the filtered signal to obtain simulated measurement values ​​of partial discharge. The IGBT module includes a rectifier circuit, an IGBT inverter circuit, a waveform generation circuit, a microcontroller, and a high-frequency transformer. The three-phase input is rectified and outputs a DC signal to the IGBT inverter circuit as the bus power supply. The microcontroller controls the waveform generation circuit to generate a periodic waveform as the signal to drive the IGBT inverter circuit. The signal generated by the IGBT inverter circuit is boosted by the high-frequency transformer.

[0025] In this embodiment, the IGBT module also includes an adjustable power load for adjusting the IGBT output power, which is connected to the output terminal of the high-frequency transformer. By setting the adjustable power load, the harmonic behavior of the IGBT under different output powers can be simulated.

[0026] In this embodiment, the frequency range of the signal driving the IGBT inverter circuit is from tens of Hz to tens of kHz.

[0027] In this embodiment, the filtering module includes a variable frequency filter.

[0028] In this embodiment, the high-frequency sensor uses an RLC series circuit.

[0029] In this embodiment, the value of at least one of the resistors, inductors, and capacitors connected in the RLC series circuit is adjustable.

[0030] In this embodiment, the RLC series circuit includes a digital potentiometer; and / or, An RLC series circuit includes at least two inductors connected in parallel and multiple relays that switch each inductor on and off; and / or An RLC series circuit includes at least two capacitors connected in parallel and multiple relays that switch each capacitor on and off.

[0031] In this embodiment, the capacitance values ​​of at least two capacitors satisfy C1=NC2, N=m², where C1 and C2 are the capacitance values ​​of two capacitors connected in parallel, and m is an integer.

[0032] In this embodiment, a three-phase bridge rectifier circuit is used.

[0033] In this embodiment, the three-phase bridge rectifier circuit includes four diodes and four thyristors. The four signals of the four thyristors VS1, VS2, VS3 and VS4 control the on and off of the four diodes respectively. VS1 and VS4 are one group, and VS2 and VS3 are another group. The two control signals in each group are the same, and the signals between the two groups are out of phase, and dead time is taken into account.

[0034] See Figure 1 In this embodiment, the three-phase input is rectified by a rectifier circuit to output a DC signal, which serves as the bus voltage for the IGBT inverter circuit. A microcontroller-controlled waveform generation circuit generates a periodic waveform as the signal driving the IGBT inverter circuit. This signal's frequency range is from tens of Hz to tens of kHz. The signal generated by the IGBT inverter circuit is boosted by a high-frequency transformer (not shown in the figure) to become the output signal U0. The output terminal is connected to an adjustable power load, allowing observation of interference harmonics under different IGBT output power levels. The output terminal is also connected to a partial discharge defect model, which discharges at a certain voltage, generating pulsating and white noise signals that are superimposed on the interference waveform generated by the IGBT. The output signal U0 is connected to a variable frequency filter, which selects the frequency of the output signal. The selected frequency can be digitally set. The signal output from the variable frequency filter is then processed by a high-frequency sensor (including coupling capacitors and detection impedance) for harmonic and discharge detection.

[0035] See Figure 2 In this embodiment, a three-phase bridge rectifier circuit composed of diodes and thyristors is used to convert the input AC signal into a DC signal output to provide the bus voltage for the IGBT module. The four signals from the four thyristors VS1, VS2, VS3, and VS4 control the on / off state of the four IGBT diodes respectively. VS1 and VS4 form one group, and VS2 and VS3 form another. The two control signals within each group are identical, and the signals between the two groups are out of phase, taking dead time into account. The periodic waveform output from the IGBT group is boosted by a high-frequency transformer, and the boosted signal is used as the output signal U0. Figure 1 The adjustable power load and partial discharge defect model in the circuit uses a filter circuit composed of L and C (C1 or C2) to select the frequency signal output. The center frequency of the selected signal is [value missing]. The selection of capacitors C1 and C2 is controlled by a relay. When A is high and B is low, capacitor C1 is selected; when A is low and B is high, capacitor C2 is selected. The interference signal output from the selected capacitor is connected to [value missing]. Figure 1 The coupling capacitor and sensing impedance are shown in the diagram. The capacitance values ​​of the two capacitors satisfy C1=NC2, N=m², where C1 and C2 are the capacitance values ​​of the two capacitors connected in parallel, and m is an integer.

[0036] See Figure 3 In other embodiments, the high-frequency sensor includes four or more capacitors connected in parallel and a relay connected to a control capacitor.

[0037] The interference generation device of Embodiment 1 of this invention, which simulates the influence of IGBTs on partial discharge detection in a converter transformer, includes an IGBT module, a partial discharge defect module, a filtering module, and a high-frequency sensor. The IGBT module controls the IGBT's on / off state and outputs a signal through a high-frequency switching signal, simulating the switching frequency signal of the IGBT in a multi-level converter transformer. The partial discharge defect module simulates and generates a mixed signal of partial discharge signal and white noise signal. The filtering module filters the simulated signal after the mixed signal and the IGBT interference signal are superimposed. The coupling capacitor and the detection impedance form a signal extraction circuit. The partial discharge instrument collects the signal at the detection impedance to obtain the simulated measurement value of partial discharge. A novel interference generation device is constructed. By simulating the actual operating conditions of the IGBT in the converter transformer through the on / off state of the IGBT, it is more accurate than simply outputting a simulated waveform. The IGBT output power is adjustable to simulate the harmonic situation of the IGBT under different power levels. The unique multi-capacitor selective access structure of the high-frequency sensor can adapt to a wide range of IGBT interference signals, ensuring measurement accuracy.

[0038] See Figure 4 This invention also discloses an interference generation method for simulating the influence of IGBTs on partial discharge detection in a converter transformer, applied to the aforementioned interference generation device for simulating the influence of IGBTs on partial discharge detection in a converter transformer. The interference generation method for simulating the influence of IGBTs on partial discharge detection in a converter transformer includes: The switching frequency interference signal of the IGBT in the multilevel converter is generated by the IGBT module. A mixed signal of partial discharge signal and white noise signal is generated by simulating the partial discharge defect module; The filtering module filters the analog signal formed by the superposition of switching frequency interference signal and mixed signal. The signal at the detection impedance is collected to obtain the simulated measurement value of partial discharge.

[0039] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes, but is not limited to, the content described in the above specific embodiments. Any modifications that do not depart from the functional and structural principles of the present invention will be included within the scope of the claims.

Claims

1. An interference generator that simulates the effect of IGBTs on partial discharge detection in a converter transformer, characterized in that: The interference generation device for simulating the effect of IGBTs on partial discharge detection in a converter transformer includes: The IGBT module generates interference signals at the switching frequency of the IGBTs in the multilevel converter transformer. The partial discharge defect module simulates and generates a mixed signal of partial discharge signal and white noise signal; The filtering module filters the analog signal formed by the superposition of switching frequency interference signals and mixed signals; Coupling capacitor; Detection impedance; The IGBT module includes a rectifier circuit, an IGBT inverter circuit, a waveform generation circuit, a microcontroller, and a high-frequency transformer. The three-phase input is rectified and outputs a DC signal to the IGBT inverter circuit as the bus power supply. The microcontroller controls the waveform generation circuit to generate a periodic waveform as the signal to drive the IGBT inverter circuit. The signal generated by the IGBT inverter circuit is boosted by the high-frequency transformer.

2. The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to claim 1, characterized in that: The IGBT module also includes an adjustable power load for adjusting the IGBT output power, which is connected to the output of the high-frequency transformer.

3. The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to claim 1, characterized in that: The frequency range of the signal driving the IGBT inverter circuit is from tens of Hz to tens of kHz.

4. The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to claim 1, characterized in that: The filtering module includes a variable frequency filter.

5. The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to claim 1, characterized in that: The filter module uses an RLC series circuit.

6. The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to claim 5, characterized in that: The value of at least one of the resistors, inductors, and capacitors connected in the RLC series circuit is adjustable.

7. The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to claim 6, characterized in that: RLC series circuits include digital potentiometers; and / or, An RLC series circuit includes at least two inductors connected in parallel and multiple relays that switch each inductor on and off; and / or An RLC series circuit includes at least two capacitors connected in parallel and multiple relays that switch each capacitor on and off.

8. The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to claim 1, characterized in that: The rectifier circuit adopts a three-phase bridge rectifier circuit.

9. The interference generating device for simulating the influence of IGBTs on partial discharge detection in a converter transformer according to claim 8, characterized in that: The three-phase bridge rectifier circuit includes four diodes and four thyristors. The four signals VS1, VS2, VS3 and VS4 of the four thyristors control the on and off of the four diodes respectively. VS1 and VS4 are one group, and VS2 and VS3 are another group. The two control signals in each group are the same, and the signals between the two groups are out of phase, and dead time is taken into account.

10. A method for generating interference to simulate the effect of IGBTs on partial discharge detection in a converter transformer, characterized in that: The interference generation device for simulating the influence of IGBTs on partial discharge detection in a converter transformer, as described in any one of claims 1 to 9, comprises the following method: The switching frequency interference signal of the IGBT in the multilevel converter is generated by the IGBT module. A mixed signal of partial discharge signal and white noise signal is generated by simulating the partial discharge defect module; The filtering module filters the analog signal formed by the superposition of switching frequency interference signal and mixed signal. The signal at the detection impedance is collected to obtain the simulated measurement value of partial discharge.

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