CN-122021193-A - High-frequency domain characteristic and time domain waveform high-precision prediction method and system of electromagnetic equipment system

CN122021193ACN 122021193 ACN122021193 ACN 122021193ACN-122021193-A

Abstract

The invention discloses a high-frequency domain characteristic and time domain waveform high-precision prediction method and a high-frequency domain characteristic and time domain waveform high-precision prediction system of an electromagnetic equipment system, comprising the following steps of (1) dividing a cable and an electromagnetic equipment winding into cascaded multi-conductor minimum units; the method comprises the steps of (1) establishing a high-precision multi-conductor minimum circuit unit model of a cable and an electromagnetic equipment winding, (3) calculating parasitic parameters through finite element simulation, setting the parameters of the minimum circuit unit model, (4) calculating transmission matrixes of the minimum circuit unit, the cable and the electromagnetic equipment winding system, (5) calculating high-frequency domain characteristics according to connection modes of the tail end of the electromagnetic equipment winding and high-frequency characteristic measurement, and (6) carrying out frequency spectrum analysis on PWM voltage output by an inverter and detecting high-frequency time domain waveforms. The method can rapidly and accurately predict the high-frequency domain and time domain characteristics of the electromagnetic equipment system in a design stage or during online operation, and has important significance for improving the reliability of the electromagnetic equipment system driven by the power electronic converter.

Inventors

DAI SHANGJIAN
CHEN FAXUAN
WANG BO
FENG JIALEI
HE MIAO
HUA WEI

Assignees

东南大学

Dates

Publication Date: 20260512
Application Date: 20260410

Claims (10)

1. The high-precision prediction method for the high-frequency domain characteristics and the time domain waveforms of the electromagnetic equipment system is characterized by comprising the following steps: The cable and the electromagnetic equipment winding are respectively divided into N c and N s multi-conductor minimum unit cascading systems; Respectively establishing high-precision multi-conductor minimum circuit unit models of cables and electromagnetic equipment; Based on impedance and capacitance parameters of a unit length cable and an electromagnetic equipment winding in a key frequency band respectively, according to the lengths of the actual cable and winding conductors corresponding to the multi-conductor minimum circuit unit model, parameters in the multi-conductor minimum circuit unit model of the cable and the electromagnetic equipment winding are calculated and determined in proportion, wherein the parameters comprise self impedance, mutual impedance, capacitance to ground, inter-phase capacitance and mutual capacitance; Calculating transmission matrixes corresponding to the minimum circuit unit models of the cable and the electromagnetic equipment based on the minimum circuit unit models of the cable and the electromagnetic equipment and the quantity of the minimum circuit unit models of the cable and the electromagnetic equipment respectively; Determining an equality relation between input/output voltage and current according to the winding end of the electromagnetic equipment and circuit connection modes during measurement of different high-frequency characteristics, and solving and obtaining the high-frequency domain characteristics of the electromagnetic equipment system driven by the power electronic converter by utilizing a circuit principle and matrix operation; And carrying out harmonic decomposition on the PWM pulse voltage output by the power electronic converter, and predicting to obtain a high-frequency time domain waveform of electromagnetic equipment under the action of the PWM pulse voltage of the power electronic converter based on the harmonic amplitude and the phase of the PWM pulse voltage and the high-frequency domain characteristic of a system, wherein the high-frequency time domain waveform comprises a winding first turn voltage peak, a neutral point voltage peak and a common mode current.
2. The method of claim 1, wherein the high-precision multi-conductor minimum circuit unit model of the cable is a2 n-terminal network, comprising n input ports and n output ports, and is composed of m-phase self-impedance, n-m core ground self-impedance, m-phase mutual capacitance and n-m core ground mutual capacitance, and the connection structure is that the self-impedance of each group of the input ports and the output ports corresponding to the ports, the mutual impedance of the other phases and the mutual impedance of the ground wires are connected in series, and the connection structure is composed of each phase capacitance/the mutual capacitance between the output ports.
3. The method of claim 1, wherein the high-precision multi-conductor minimum circuit unit model of the electromagnetic equipment is a two-port network structure representing an actual single-turn winding and is composed of self inductance, self resistance, ground capacitance and mutual capacitance of the single-turn winding, and the connection structure is that each input port and each output port are connected in series by self impedance of the turn and mutual impedance between the turn and other turns and are connected in parallel with the mutual capacitance of the next-turn winding, the input port is connected to ground by half turn of the turn to ground capacitance, and the output port is connected to ground by the other half of the turn to ground capacitance.
4. A method according to claim 3, wherein the two-port network structure connects two-port network ground wires corresponding to single-turn windings of different phases when m is greater than or equal to 2, namely for electromagnetic equipment with multi-phase windings, thereby obtaining a2 (m+1) end network, and forming a high-precision multi-conductor minimum circuit unit model of the electromagnetic equipment.
5. The method according to claim 1, wherein the impedance and capacitance parameters of the unit length cable and the electromagnetic equipment winding in the critical frequency range are obtained by respectively establishing a finite element electromagnetic simulation model of the cable and the electromagnetic equipment, calculating by using a built-in electrostatic field simulator and a vortex field simulator to obtain self-impedance, transimpedance, capacitance to ground, inter-phase capacitance and mutual capacitance of the unit length cable and the electromagnetic equipment winding, wherein the setting of the critical frequency range comprises main resonance frequencies of the cable and the electromagnetic equipment, and the setting range is 100kHz to 100MHz.
6. The method according to claim 1, wherein the transmission matrices corresponding to the minimum circuit unit models of the cable and the electromagnetic equipment are calculated by firstly respectively obtaining admittance matrices representing the relation between the input voltage vector [ U i , U o ] and the input output current [ I i , I o ] according to the minimum circuit unit models of the cable and the electromagnetic equipment, then converting the admittance matrices into the transmission matrices representing the relation between the input voltage current vector [ U i , I i ] and the output voltage current [ U o , I o ] according to matrix operation, obtaining transmission matrices T c and T s of the minimum circuit unit models of the cable and the electromagnetic equipment respectively, and then obtaining transmission matrices (T c ) Nc and (T s ) Ns ) of the cable and the electromagnetic equipment according to the minimum unit numbers N c and N s , respectively, and performing the secondary operation.
7. The method of claim 6, wherein the power electronic converter-driven electromagnetic equipment system has high frequency domain characteristics, and the specific solving steps are as follows: Determining two equality relations between the input voltage and the output current U i , U o , I i , I o based on the transmission matrix, and determining the equality relation of the tail end output voltage and the output current U o , I o according to the connection form of the tail ends of the winding of the electromagnetic equipment; According to the relation of the voltage-current equation corresponding to different circuit connection forms during high-frequency characteristic measurement, the input current I i (s), the output voltage current U o (s), I o (s) and the voltage U p of a key node of a system under U i (s) under different input voltage excitation are obtained by utilizing a circuit principle and matrix operation solution ) S is the complex frequency; And then will be Substituting to obtain the high-frequency domain characteristic of the electromagnetic equipment system driven by the power electronic converter, In imaginary units, f is frequency.
8. The method of claim 7, wherein the high frequency domain characteristics of the electromagnetic equipment system driven by the power electronic converter include common mode impedance curves and differential mode impedance curves of the cable, the electromagnetic equipment winding and the system formed by the cable and the electromagnetic equipment, transfer functions of first turn voltage of the electromagnetic equipment winding relative to output voltage of the power electronic converter, transfer functions of neutral point of the electromagnetic equipment winding relative to output voltage of the power electronic converter, and input voltages U i which are obtained by various impedance curves according to corresponding measuring circuit connection ) Dividing input current I i ) Obtaining the node voltage U p which is obtained by various transfer functions according to the corresponding measuring circuit connection ) Divided by input current U i % ) Obtained.
9. The method according to claim 8, wherein the specific prediction step of the high-frequency time domain waveform of the electromagnetic equipment under the action of the PWM pulse voltage of the power electronic converter is as follows: Firstly, carrying out Fourier decomposition on the output voltage of an inverter, taking a switching frequency secondary alternating current component as a fundamental wave, and taking the upper limit of the equivalent effective bandwidth of PWM pulse voltage as the highest harmonic wave to obtain the amplitude and the phase of each frequency PWM pulse voltage harmonic wave; Then, according to the transfer function of the first turn voltage of the electromagnetic equipment winding relative to the output voltage of the power electronic converter, the transfer function of the neutral voltage of the electromagnetic equipment winding relative to the output voltage of the power electronic converter and the common mode impedance curve, frequency domain responses of the first turn voltage, the neutral point voltage and the common mode current of the electromagnetic equipment winding under the action of each subharmonic of PWM pulse voltage of the power electronic converter are respectively obtained; And finally, adding the results of the action of each subharmonic, and converting the frequency domain response waveform back to the time domain by utilizing Fourier inversion conversion to obtain the high-frequency time domain waveform of the first turn voltage peak, the neutral point voltage peak and the common mode current of the electromagnetic equipment winding driven by the power electronic converter.
10. An electronic system comprising at least one processor and a memory communicatively coupled to the at least one processor, wherein the memory stores instructions executable by the at least one processor, wherein the instructions are executable by the at least one processor to enable the at least one processor to perform the method steps recited in any one of claims 1-6.

Description

High-frequency domain characteristic and time domain waveform high-precision prediction method and system of electromagnetic equipment system Technical Field The invention belongs to the technical field of modeling and prediction of power electronics and electromagnetic equipment systems, and relates to a high-frequency domain characteristic and time domain waveform high-precision prediction method and system of an electromagnetic equipment system. Background With rapid development of power electronics technology, a power electronic converter based on PWM (Pulse-Width Modulation) technology is widely used in various electromagnetic equipment systems such as motors, transformers, reactors, inductors, and the like. In order to improve the power density and efficiency of the system, the switching frequency of the power electronic converter is continuously improved, but the high frequency brings negative effects of high voltage peak, high common mode current, high EMI (Electromagnetic Interference ) and the like, and the reliability of the electromagnetic equipment system is obviously reduced. The high frequency negative effect of the power electronic converter drive is essentially that under high frequency PWM excitation, strong coupling of internal parasitic parameters of the electromagnetic equipment and its connection lines occurs, inducing undesired resonance. For example, in systems driven by an inverter via long cables, PWM voltages at high slew rates can produce high frequency voltage spikes at the winding head turns, neutral points, or other equivalent nodes that are significantly amplified in magnitude, resulting in excessive voltage stress to the winding insulation. When the stress exceeds PDIV (PARTIAL DISCHARGE Inception Voltage, partial discharge initiation voltage), partial discharge is generated, and as discharge is accumulated, the PDIV is lowered, partial discharge is aggravated, and insulation degradation is accelerated and equipment life is shortened finally. Therefore, the winding head turns, neutral points or equivalent neutral nodes are usually weak points of voltage stress, and important attention should be paid. The voltage spike oscillation frequencies that occur at different nodes typically correspond to the associated resonant frequencies of the system common mode/differential mode impedance. Document 1（M. Memon, M. Diab, and X. Yuan, "Mitigation of Machine Neutral Point Overvoltage in SiC Motor Drives by Controlling Antiresonance Frequency and Switching Frequency," IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 13, no. 2, pp. 1514-1527, 2025） teaches that as the common mode impedance resonant frequency of a system of cables and electromagnetic equipment approaches the converter switching frequency, spikes up to 6 times the bus voltage can occur at the neutral point. Therefore, the high-frequency domain characteristics and the time domain waveforms of the electromagnetic equipment driven by the power electronic converter are accurately and rapidly predicted in the design stage or in the online operation, and the method has important significance for evaluating the high-frequency negative influence of the electromagnetic equipment system caused by the power electronic converter and taking targeted optimization measures. The existing high-precision prediction means is mainly based on time domain simulation of a refined multi-conductor transmission line circuit model, and can predict a system impedance curve, a winding head turn/neutral point voltage peak and a common mode current in a design stage through circuit simulation software, see literature 2（S. Sundeep, J. Wang, and A. Griffo, "Holistic Modeling of High-Frequency Behavior of Inverter-Fed Machine Winding, Considering Mutual Couplings in Time Domain," IEEE Transactions on Industry Applications, vol. 57, no. 6, pp. 6044-6057, 2021）., but the method is complex in modeling, frequency-dependent parameter fitting is required, simulation time is long, calculation time is obviously increased along with the length of a cable and the number of turns of a winding, simulation time of a long cable or a multi-turn winding system can reach a level or a level of circumference, rapid evaluation requirements in the design stage or on-line operation are difficult to meet, and optimization design and on-line reliable operation and maintenance implementation of a high-frequency matching and dv/dt filter are influenced. Disclosure of Invention The invention aims to solve the technical problem of providing a general and efficient high-precision prediction method for high-frequency domain characteristics and time domain waveforms of an electromagnetic equipment system driven by a power electronic converter, wherein the electromagnetic equipment comprises, but is not limited to, electromagnetic equipment with windings or multi-conductor structures such as a motor, a transformer, a reactor, an inductor and the like, so that the