Silicon carbide electric drive common-mode and differential-mode voltage suppression method, device and equipment

Abstract

The invention discloses a silicon carbide electric drive common-mode and differential-mode voltage suppression method, device and equipment. The method comprises the following steps: acquiring a multi-vector pulse sequence of an inverter in a silicon carbide electric drive system; solving the action time of each voltage vector in the multi-vector pulse sequence; and based on the action time of each voltage vector, constructing an evaluation function, and selecting a sequence of the minimum evaluation function as an optimal sequence and outputting the optimal sequence. According to the invention, by optimizing the multi-vector pulse sequence and action time distribution, the cooperative suppression of common-mode and differential-mode voltages can be realized, and the current control precision and the system response performance are improved at the same time.

Description

Technical Field

[0001] This application belongs to the technical field of power electronics and motor control, and specifically relates to a method, device, and equipment for suppressing common-mode and differential-mode voltages of a silicon carbide electric drive. Background Art

[0002] Silicon carbide (SiC) power devices have been widely used in permanent magnet synchronous motor (PMSM) drive systems due to their advantages such as high switching frequency and low conduction loss. However, due to their high-speed switching characteristics, the rate of voltage change (dv / dt) is extremely high, and high-frequency common-mode voltage and large-amplitude differential-mode voltage are easily generated during the drive process. Among them, the common-mode voltage induces a relatively high shaft voltage on the motor shaft, which in turn induces bearing current, causing premature wear or even failure of the bearings; the differential-mode voltage may form a spike voltage at the motor winding terminals, and its peak value can reach 3 times the DC bus voltage, seriously threatening the reliability of the winding insulation system.

[0003] Traditional suppression schemes mainly include two categories: one is to alleviate by enhancing insulation design or introducing hardware means such as passive filters, but such methods often have high costs, large volumes, and resonance risks; the other is to reduce voltage interference through specific modulation modes or active control strategies such as model predictive control (MPC). However, most of the existing MPC methods fail to achieve the coordinated suppression of common-mode voltage (CMV) and differential-mode voltage (DMV), and there are deficiencies in considering the dead-time effect, which is likely to induce unpredictable common-mode spikes and differential-mode overshoots during the dead-time of the bridge arm.

[0004] Therefore, there is an urgent need for a high-performance control method that can take into account the suppression of CMV and DMV, and at the same time improve the current control accuracy and dynamic performance to meet the dual requirements of electromagnetic compatibility and motor insulation reliability of the SiC electric drive system. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the main purpose of this application is to provide a method, device, and equipment for suppressing common-mode and differential-mode voltages of a silicon carbide electric drive, aiming to improve the electromagnetic compatibility and insulation reliability of a permanent magnet synchronous motor (PMSM) driven by a SiC inverter.

[0006] To achieve the above objectives, this application provides the following technical solutions: A method for suppressing common-mode and differential-mode voltages of a silicon carbide electric drive, the method includes: obtaining a multi-vector pulse sequence of an inverter in the silicon carbide electric drive system; solving the action time of each voltage vector in the multi-vector pulse sequence; based on the action time of each voltage vector, constructing an evaluation function, and selecting the sequence with the minimum evaluation function as the optimal sequence and outputting it.

[0007] Optionally, obtaining the multi-vector pulse sequence of the inverter in the silicon carbide electric drive system includes: dividing the non-zero voltage vectors output by the inverter in the silicon carbide electric drive system into sectors; adaptively selecting a vector sequence based on the divided sectors in combination with the modulation index m.

[0008] Optionally, solving the action time of each voltage vector in the multi-vector pulse sequence includes: compensating for the one-beat delay of the system during predictive control to obtain the predicted current value for the next beat; solving the action time of each vector based on the predicted current value for the next beat.

[0009] Optionally, based on the action time of each voltage vector, constructing an evaluation function, and selecting the sequence with the minimum evaluation function as the optimal sequence and outputting it includes: constructing an evaluation function; calculating the corresponding current prediction error for each candidate pulse sequence, substituting it into the evaluation function, and selecting the pulse sequence that minimizes the evaluation function value as the optimal output.

[0010] This application also provides a silicon carbide electric drive common-mode and differential-mode voltage suppression device, which includes: an acquisition module for acquiring the multi-vector pulse sequence of the inverter in the silicon carbide electric drive system; a solution module for solving the action time of each voltage vector in the multi-vector pulse sequence; and a selection module for constructing an evaluation function based on the action time of each voltage vector, and selecting the sequence with the minimum evaluation function as the optimal sequence and outputting it.

[0011] This application also provides an electronic device, which includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the program, it implements the method described in any one of the previous items.

[0012] This application can bring the following technical effects: Through the design of the multi-vector pulse sequence based on voltage sector division, combined with the one-beat delay compensation and action time optimization method, this application realizes high-precision predictive control of the motor current, and while improving the dynamic response and steady-state tracking performance, effectively suppresses the common-mode voltage spikes and differential-mode voltage overshoots caused by factors such as dead-time effect and high dv / dt, improves the electromagnetic compatibility of the system and the motor insulation protection ability, and has better control performance, reliability and engineering applicability. Description of the Drawings

[0013] Figure 1 is a schematic flowchart of a silicon carbide electric drive common-mode and differential-mode voltage suppression method provided by an embodiment of this application; Figure 2 is a schematic diagram of three-phase current sector division provided by another embodiment of this application; Figure 3 is a schematic diagram of PWM signal comparison before and after adding dead-time; Figure 4 It is a schematic diagram of the freewheeling state during the dead time when the first current direction is present; Figure 5 It is a schematic diagram of the freewheeling state during the dead time when the second current direction is present; Figure 6 It is a schematic diagram of the equivalent circuit of the VSI inverter - cable - PMSM system provided by another embodiment of the present application; Figure 7 It is a schematic diagram of the waveforms of the common - mode voltage and differential - mode voltage provided by another embodiment of the present application; Figure 8 It is a schematic diagram of the six - segment basic voltage vectors and sector division provided by another embodiment of the present application; Figure 9 It is a schematic diagram of two vectors provided by another embodiment of the present application; Figure 10 It is a schematic diagram of three vectors provided by another embodiment of the present application; Figure 11 It is a schematic diagram of four vectors provided by another embodiment of the present application; Figure 12 It is a simulation curve graph of the differential - mode voltage when the modulation index m < 0.61 provided by another embodiment of the present application; Figure 13 It is a simulation curve graph of the common - mode voltage when the modulation index m < 0.61 provided by another embodiment of the present application; Figure 14 It is a simulation curve graph of the differential - mode voltage when the modulation index m ≥ 0.61 provided by another embodiment of the present application; Figure 15 It is a simulation curve graph of the common - mode voltage when the modulation index m ≥ 0.61 provided by another embodiment of the present application; Figure 16 It is a schematic diagram of the experimental waveform of the differential - mode voltage of the traditional common - mode voltage suppression method (MPC - I) when the modulation index m < 0.61; Figure 17 It is a schematic diagram of the experimental waveform of the differential - mode voltage of the common - mode voltage suppression method considering dead time (MPC - II) when the modulation index m < 0.61; Figure 18 It is a schematic diagram of the experimental waveform of the differential - mode voltage when the modulation index m < 0.61 provided by an embodiment of the present application; Figure 19 It is a schematic diagram of the differential - mode voltage amplification of the traditional common - mode voltage suppression method (MPC - I) when the modulation index m < 0.61; Figure 20 It is a schematic diagram of the differential - mode voltage amplification of the common - mode voltage suppression method considering dead time (MPC - II) when the modulation index m < 0.61; Figure 21 It is a schematic diagram of differential-mode voltage amplification when the modulation index m < 0.61 provided by an embodiment of the present application; Figure 22 It is a schematic diagram comparing the current THD of the traditional common-mode voltage suppression method (MPC-I), the common-mode voltage suppression method considering dead time (MPC-II), and the present application at different speeds; Figure 23 It is a schematic diagram comparing the electromagnetic torque ripple of the traditional common-mode voltage suppression method (MPC-I), the common-mode voltage suppression method considering dead time (MPC-II), and the present application at different speeds; Figure 24 It is a schematic diagram comparing the average switching frequency of the traditional common-mode voltage suppression method (MPC-I), the common-mode voltage suppression method considering dead time (MPC-II), and the present application at different speeds; Figure 25 It is a comparison chart of the calculation time of three control methods provided by another embodiment of the present application. Detailed implementation manners

[0014] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0015] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present application are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0016] In the present application, unless otherwise clearly specified and defined, terms such as "connection" and "fixation" shall be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0017] In addition, if descriptions such as "first" and "second" are involved in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and / or" appearing throughout the text includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present application.

[0018] Figure 1 is a schematic flowchart of a method for suppressing common-mode and differential-mode voltages of a silicon carbide electric drive provided by an exemplary embodiment of the present application. As Figure 1 described, the method includes the following steps: S100: Obtain the multi-vector pulse sequence of the inverter in the silicon carbide electric drive system; S200: Solve the action time of each voltage vector in the multi-vector pulse sequence; S300: Based on the action time of each voltage vector, construct an evaluation function, and select the sequence with the minimum evaluation function as the optimal sequence and output it.

[0019] In another exemplary embodiment, in step S100, the obtaining of the multi-vector pulse sequence of the inverter in the silicon carbide electric drive system includes the following steps: S101: Divide the non-zero voltage vectors output by the inverter in the silicon carbide electric drive system into sectors; In this step, first, the non-zero voltage vectors output by the inverter in the silicon carbide electric drive system are initially divided to identify the equivalent zero vectors that may be generated when the initial voltage vectors are switched under different sectors, as shown in Table 1 specifically: Table 1

[0020] As shown in Table 1, in sectors 1, 3, and 5, the switching of the initial vector combinations will generate equivalent zero vectors u 0, and in sectors 2, 4, and 6, the switching of the initial vector combinations will generate equivalent zero vectors u 7. By generating the equivalent zero vectors u 0 and u7. It can provide basic rules for the subsequent pulse sequence design, thus avoiding the risk of directly using dangerous vector combinations. In each sector where a voltage vector is located, whether an equivalent zero vector (such as u0 or u7) will be generated depends on the specific distribution of the three-phase currents in that sector. As Figure 2 shown, the instantaneous directions and magnitudes of the three-phase currents i a , i b , i c determine the conduction states of the bridge arms during the dead time, and thus affect the formation of the equivalent zero vector. Specifically, in sectors 1, 3, and 5, if the current direction combinations meet certain specific conditions, an equivalent zero voltage vector u 0 may be formed through the freewheeling paths of the upper and lower bridge arms during the dead time; while in sectors 2, 4, and 6, an equivalent zero vector u 7 may be formed. The generation of this equivalent zero vector is not only affected by the voltage vector combination of the selected pulse sequence, but also by the dynamic coupling of the current direction and the motor operating state. Therefore, when designing the pulse sequence, it is necessary to comprehensively consider the voltage sector and the real-time three-phase current direction to avoid generating undesired common-mode voltage spikes and improve the safety and robustness of the control strategy.

[0021] In addition, equivalent zero voltage vectors may also be generated within the designed pulse sequence during the dead time, as shown in Table 2.

[0022] Table 2

[0023] Table 2 specifically describes that within the pulse sequence, due to the existence of the dead time, certain repeated or specific-order voltage vector combinations will generate equivalent zero vectors (such as u0 or u7), resulting in common-mode voltage spikes. For example, for sectors 1, 3, and 5, the corresponding sequences are all equivalent to u 0 during the dead time, and for sectors 2, 4, and 6, the corresponding sequences are all equivalent to u 7 during the dead time. Table 2 reveals that in the complete pulse sequence, even if the initial vector switching is safe (avoided through Table 1), if there are repeated or symmetric vector combinations within the sequence (such as u 1 -u 5 -u 1), equivalent zero vectors may still be generated. That is, as a supplement to the static rules shown in Table 1, Table 2 can dynamically analyze the potential risks of sequence construction in actual control.

[0024] Figure 3 is a comparison diagram of the PWM signals before and after adding the dead time. As Figure 3 shown, during the dead time td Within this period, the PWM signal is in the low level state. At this time, the upper and lower switching devices of the same bridge arm are both turned off, and the current conducts through the upper or lower freewheeling diode, resulting in an uncertain output state of the bridge arm. Under different current directions, this output state may present high level, low level or zero level, thus triggering a sudden change in the common-mode voltage.

[0025] Figure 4 and Figure 5 are the freewheeling state diagrams during the dead time. As shown in Figure 4 and Figure 5 When the voltage vector switches from 100 to 010, it shows the comparison of the influence of different phase current directions on the common-mode voltage during the dead time. When the current direction is as shown in Figure 4 shown i a >0, i b >0, i c <0, an equivalent zero vector 000 will be generated, causing the common-mode voltage to instantaneously rise to U dc / 2; while in the direction shown in Figure 5 , no equivalent zero vector will be formed, thus effectively avoiding this spike. Therefore, it is necessary to limit the direct switching of adjacent vectors in the pulse sequence to avoid potential spike common-mode voltage within the dead time. In addition, Figure 6 shows the equivalent circuit structure of the VSI (Voltage Source Inverter)-cable-PMSM (Permanent Magnet Synchronous Motor) system, which can be used to analyze the electromagnetic interference and voltage response characteristics. This equivalent circuit structure clearly depicts the actual topology where the output side of the inverter is connected to the input end of the motor through a long cable. In this structure, the distributed inductance, capacitance and impedance of the cable, together with the input impedance of the motor body, constitute a typical distributed parameter system. As shown in Figure 7 , during the rapid switching of the voltage vector, due to the mismatch between the cable impedance and the motor impedance, reflection and superposition effects will occur, thus causing obvious differential-mode voltage oscillations at the motor terminal. This oscillation not only affects the quality of the current waveform, but may also impact the insulation of the motor winding, reducing the electromagnetic compatibility and reliability of the system. Therefore, in the actual control strategy, it is necessary to fully consider the influence of voltage vector switching on the response of the cable-load system, and by restricting the vector combinations with high dv / dt changes in the pulse sequence, or adopting a modulation method with slow-changing characteristics, to effectively reduce the transient impact and oscillation amplitude of the differential-mode voltage, thereby improving the stability of the system and the service life of the motor.

[0026] S102: Based on the divided sectors, adaptively select the vector sequence in combination with the modulation index m.

[0027] In this step, to further improve the flexibility and control accuracy of the modulation strategy, based on the equivalent zero-vector constraint conditions proposed in Table 1 and Table 2, this application further divides the six basic non-zero voltage vectors of the VSI inverter to construct 12 equally spaced small sectors, as Figure 8 shown. Each small sector is defined within the region between two adjacent basic vectors. For example, sector 1 covers u the space between u 1 and u 2, sector 2 covers u the region between 2 and

[0028] 3, and so on, forming a complete space vector division. Figure 9 shows the effective modulation region based on two-vector combination, which has a simple structure and is suitable for high-frequency switching scenarios; Figure 10 shows the three-vector combination modulation method, which can provide more precise voltage approximation accuracy; Figure 11 introduces a four-vector pulse sequence, which can effectively expand the modulation linear range and enhance the comprehensive suppression ability of common-mode and differential-mode voltages under low modulation degrees.

[0029] By introducing the above multi-vector modulation strategies, not only the entire two-level space vector diagram is comprehensively covered, but also the adaptability of the control system under different modulation degrees and dynamic operating conditions is significantly improved, providing a wider voltage vector selection space for implementing high-performance model predictive control and effectively balancing the contradiction between system control performance and electromagnetic interference suppression.

[0030] In addition, this application dynamically selects M-type or N-type pulse sequences according to the modulation degree, as shown in Table 3 specifically: Table 3

[0031] As can be seen from Table 3, when the modulation degree m < 0.61, a pulse sequence composed of 4 voltage vectors is adopted, that is, the M-type sequence (4 vectors, such as M1: u 3 - u 2 - u 1 - u 6 - u 1 - u 2 - u 3); when the modulation degree m > 0.61, a pulse sequence composed of 3 voltage vectors is adopted, that is, the N-type sequence (3 vectors, such as N1: u 6 - u 1 - u 2 - u 1 - u 6).

[0032] In Table 3, the M1 sequence of Sector 1 ( u 3- u 2- u 1- u 6- u 1- u 2- u 3) completely avoids the u 1- u 5 combination in Table 1 and instead uses u 1- u 6- u 1 transition. The N1 sequence ( u 6- u 1- u 2- u 1- u 6) avoids the u 1- u 5- u 1 and other dangerous internal combinations in Table 2 through symmetric arrangement. For example, for Sector 1, Table 3 selects the M1 sequence ( u 3- u 2- u 1- u 6- u 1- u 2- u 3), which does not include the u 1- u 5- u 1 combination in Table 2 and successfully avoids the equivalent zero vector.

[0033] In summary, Tables 1 and 2 provide constraints, that is, by defining all possible dangerous scenarios that can generate equivalent zero vectors, a "forbidden zone" is delimited for the pulse sequence design in Table 3. Table 3 generates an optimized scheme based on the constraints, that is, by dynamically selecting M and N type sequences and combining the modulation degree and sector information, it ensures that the pulse sequence can not only meet the performance requirements but also avoid the risk of equivalent zero vectors.

[0034] In another exemplary embodiment, in step S200, solving for the action time of each voltage vector in the multi-vector pulse sequence includes the following steps: S201: Predict the one-beat delay of the compensation system during predictive control to obtain the predicted current value for the next beat; In this step, first perform time base alignment, and shift the control target from the current moment to the next control moment , that is, at moment calculate and apply the optimal control action for moment. Predict the reference current one frame in advance, based on Calculation of the state at a moment.

[0035] Secondly, based on the system dynamic equation, perform a one-step forward prediction on the current state to obtain the predicted values of the currents on the ) axis and axis current prediction values , :

[0036]

[0037] Among them, represents the axis current at the current moment; represents the axis current at the next moment ; represents the control period; represents the stator inductance; represents the axis voltage at the current moment; represents the stator resistance; represents the electrical angular velocity of the motor; represents the axis current at the current moment; represents the axis current at the next moment ; represents the axis voltage at the current moment; represents the permanent magnet flux linkage.

[0038] By advancing the reference value of the target current to the next control period, this step can align the time reference of the control target with the system response, thereby overcoming the control lag problem caused by calculation delay and execution lag in traditional model predictive control (MPC). The principle is as follows: At the moment , based on the current system state, predict the current at the moment , and use this as the optimization target to solve the optimal control action in advance, so that this action is at When applied at the right moment, it can precisely track the target current. This "predictive control" mechanism essentially introduces a one-step feedforward compensation to the system, enabling MPC to no longer be limited to responding to the current state but to make optimized decisions for future states, thereby significantly enhancing the dynamic response speed and steady-state error convergence ability. This method can effectively suppress current fluctuations, shorten the adjustment time, and improve the robustness and precision of the system under rapid load changes or high-frequency interference, significantly enhancing the practicality and engineering adaptability of the control strategy.

[0039] S202: Solve the action time of each vector based on the predicted value of the next-step current, and the specific calculation is carried out according to the following formula:

[0040]

[0041] Among them, represents d the given value of the d-axis current, which generally depends on the flux linkage control strategy and is usually zero in a surface-mounted permanent magnet synchronous motor; represents the given value of the q-axis current, which is usually generated by the torque demand or the speed outer-loop controller and determines the motor output torque; represents the predicted d-axis current at time ; represents the predicted q-axis current at time ; , and respectively represent the contribution coefficients of the three voltage vectors to the d-axis current change rate; t x , t y , t z respectively represent the action times of the voltage vectors x , y , z ; represents the control period, which is equal to the sum of the action times of the voltage vectors x , y , z ; represents the d-axis current change rate, which reflects the regulation ability of voltage, speed, and stator parameters on the d-axis current; represents the q-axis current change rate, which reflects the regulation ability of voltage, speed, stator parameters, and flux linkage on the q-axis current; , respectively represent the voltage components of the corresponding vector at the moment in the axis and axis directions; represents the stator resistance; , respectively represent of axis and axis current predicted values; represents the electrical angular velocity of the motor; , respectively represent axis, axis inductance; represents the permanent magnet flux linkage. The above Equation 1 establishes the relationship between current regulation and vector action time. The above Equation 2 defines the action mechanism of voltage on the current change rate. By solving the above equations, the action times of the three voltage vectors x, y, z can be obtained t x , t y , t z .

[0042] It should be noted that when the modulation degree satisfies m < 0.61, the pulse sequence is composed of four voltage vectors at this time, but two of the voltage vectors are opposite, and the two constitute a virtual zero vector. Therefore, when solving, these two opposite voltage vectors can be regarded as zero vectors for solution. The following takes the voltage vectors u 6, u 1, u 2, u 3 in the first sector as an example for calculation. At this time, u 6, u 3 are regarded as the virtual zero vector u 0 for calculation. The specific solution process is the same as when m ≥ 0.61, but after finally solving the action time of the virtual zero vector, it needs to be evenly distributed to the two voltage vectors u 6, u 3.

[0043] This step optimizes and solves the action times of the voltage vectors included in each candidate pulse sequence, establishes a quantitative relationship between the voltage vectors and the target current, and thus realizes high-precision tracking of the target current in the next control cycle. Its principle is based on the voltage-current state equation of the permanent magnet synchronous motor, and the voltage vectors in the dqThe influence on the current change rate under the axis coordinate system is modeled as a linear combination. By solving a system of linear equations, the optimal action time of different voltage vectors is determined, so that the current change trajectory within a control period is as close as possible to the desired reference value. This optimization process not only considers the influence of motor parameters, electrical angular velocity and magnetic flux, but also introduces a virtual zero vector allocation strategy to handle the voltage non-ideality caused by dead zone effects. This method enables the control system to achieve fine adjustment of the current dynamic change within a limited action time, thereby significantly improving the control accuracy, shortening the response delay, and maintaining the stable operation of the system in the face of load disturbances or voltage interferences, effectively enhancing the application value and robustness of model predictive control in high-performance motor drive systems. At the same time, on the basis of meeting the current regulation performance, this solution process fully considers the comprehensive suppression effect of common-mode voltage and differential-mode voltage. By reasonably allocating the action time of each voltage vector, it effectively reduces the high-frequency common-mode spikes and differential-mode overshoot phenomena, improves the electromagnetic compatibility of the system and the motor insulation protection ability, realizes the coordinated optimization of current performance and voltage suppression, and enhances the practical application effect and engineering adaptability of the control strategy.

[0044] In another exemplary embodiment, in step S300, based on the action time of each voltage vector, an evaluation function is constructed, and the sequence with the minimum evaluation function is selected as the optimal sequence and output, including the following steps: S301: Construct an evaluation function, specifically as follows:

[0045] Wherein, G represents the evaluation function value; represents the given value of the axis current; represents the given value of the axis current; represents the predicted axis current at the future moment; represents the predicted axis current at the future moment; represents the predicted values of the and axis currents obtained by one-beat compensation.

[0046] The above-mentioned evaluation function evaluates the control effect by comparing the squared error between the current prediction value and the target value. Among them, if the error is small, then G is small, indicating that the current pulse sequence helps to achieve the ideal current target; if the error is large, then G is large, indicating that the current sequence control performance is poor. Therefore, select the one that makes GThe minimum pulse sequence is used as the optimal sequence for the current control period, which can improve the current regulation performance and meet the dual requirements of dynamic response and steady-state accuracy.

[0047] S302: Calculate the corresponding current prediction error for each candidate pulse sequence, substitute it into the evaluation function, and select the pulse sequence that minimizes the evaluation function value as the optimal output.

[0048] In this step, the permanent magnet synchronous motor is dq The voltage equation in the coordinate system is:

[0049] Among them, the expression of the magnetic flux linkage is:

[0050] Among them, represents axis voltage; represents axis voltage; represents axis current; represents axis current; represents axis magnetic flux linkage; represents axis magnetic flux linkage. Substitute the magnetic flux linkage equation into the voltage equation, and at the same time transform the above voltage equation to obtain the current equation in the form of:

[0051] Then, use the forward Euler method to discretize the differential term to obtain the prediction equation:

[0052] From the current prediction equation, it can be known that the , in the equation are the key variables participating in the prediction. Then, the voltage vectors in the pulse sequence are vectorially synthesized to obtain a synthesized voltage vector u d1 , u q1 . Then, substitute the synthesized voltage vector of each sequence into the current prediction equation to obtain the current prediction values , . Through , making another prediction, the , can be obtained.

[0053] The common-mode voltage and differential-mode voltage suppression method proposed in this application has been fully verified on a simulation platform and a three-phase inverter-PMSM physical platform. The relevant effects are as Figures 12 to 25 shown. Under the condition that the modulation index m < 0.61, Figure 12 and Figure 13 respectively show the simulation curves of the differential-mode voltage and the common-mode voltage. Under the condition that the modulation index m ≥ 0.61, the corresponding simulation results are shown in Figure 14 and Figure 15 . The above four figures show that: this method can not only effectively suppress the high-frequency common-mode voltage spikes, but also significantly alleviate the differential-mode voltage oscillation problem caused by the impedance mismatch of cables and motors under different modulation indexes, enhancing the electromagnetic compatibility of the system.

[0054] Furthermore, Figure 16 and Figure 19 show the experimental waveforms of the differential-mode voltage of the traditional MPC-I method when the modulation index m < 0.61. It can be observed from the figure that there are obvious spike phenomena. Figure 17 and Figure 20 are the experimental waveforms of the MPC-II method considering the dead time under the same modulation index. Although some spikes are alleviated, there are still overshoot problems that cannot be ignored. In contrast, Figure 18 and Figure 21 clearly show that after adopting the control strategy proposed in this application, the maximum amplitude of the differential-mode voltage decreases significantly, and the spikes are effectively limited within twice the DC bus voltage. Compared with the situation where the MPC-I may reach three times the bus voltage, the safety margin is greatly improved, significantly reducing the impact risk on the motor insulation system.

[0055] In addition, to comprehensively evaluate the control performance, Figures 22 to 25 respectively give the comparison of the key performance indicators of the three methods at different motor speeds: Figure 22 shows that this application achieves a lower total harmonic distortion (THD) of current at different speeds, indicating that its steady-state regulation ability is not impaired due to common-mode / differential-mode suppression, and even better than the traditional method. Figure 23 The results of Figure 24 show that under dynamic conditions, this method can significantly reduce the electromagnetic torque ripple, which is beneficial to the smooth operation of the system. Figure 25 The comparison results of the average switching frequency shown in

[0056] In summary, the suppression strategy proposed in this application is not only verified to be effective in simulations, but also demonstrates excellent current control performance, voltage suppression ability, and engineering feasibility in physical systems. It provides an optimized control scheme that takes into account accuracy, robustness, and implementation efficiency for high-performance motor systems driven by SiC inverters.

[0057] In another exemplary embodiment, the present application further provides a SiC electric drive common-mode and differential-mode voltage suppression device, which includes: an acquisition module for acquiring a multi-vector pulse sequence of an inverter in a SiC electric drive system; a solution module for solving the action time of each voltage vector in the multi-vector pulse sequence; and a selection module for constructing an evaluation function based on the action time of each voltage vector, and selecting the sequence with the minimum evaluation function as the optimal sequence and outputting it.

[0058] In another exemplary embodiment, the present application further provides an electronic device, which includes: a memory, a processor, and a computer program stored on the memory and executable on the processor, wherein when the processor executes the program, it implements the method described in any one of the preceding items.

[0059] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structural or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present application.

Claims

1. A method for suppressing common-mode and differential-mode voltages of a silicon carbide electric drive, characterized in that The method includes: Obtaining a multi-vector pulse sequence of an inverter in a silicon carbide electric drive system; Solving the action time of each voltage vector in the multi-vector pulse sequence; Based on the action time of each voltage vector, constructing an evaluation function, and selecting the sequence with the minimum evaluation function as the optimal sequence and outputting it.

2. The method according to claim 1, characterized in that, The obtaining of the multi-vector pulse sequence of the inverter in the silicon carbide electric drive system includes: Dividing the non-zero voltage vectors output by the inverter in the silicon carbide electric drive system into sectors; Based on the divided sectors, adaptively selecting a vector sequence in combination with the modulation index m to obtain a multi-vector pulse sequence.

3. The method according to claim 1, characterized in that The solving of the action time of each voltage vector in the multi-vector pulse sequence includes: Compensating for the one-beat delay of the system during predictive control to obtain the predicted current value of the next beat; Solving the action time of each vector based on the predicted current value of the next beat.

4. The method according to claim 1, wherein The constructing of the evaluation function based on the action time of each voltage vector, and selecting the sequence with the minimum evaluation function as the optimal sequence and outputting it includes: Constructing an evaluation function; Calculating the corresponding current prediction error for each candidate pulse sequence, substituting it into the evaluation function, and selecting the pulse sequence that minimizes the evaluation function value as the optimal output.

5. A silicon carbide electric drive common-mode and differential-mode voltage suppression device, characterized in that, The device includes: An obtaining module, configured to obtain a multi-vector pulse sequence of an inverter in a silicon carbide electric drive system; A solving module, configured to solve the action time of each voltage vector in the multi-vector pulse sequence; A selecting module, configured to construct an evaluation function based on the action time of each voltage vector, and select the sequence with the minimum evaluation function as the optimal sequence and output it.

6. An electronic device, characterized in that, The electronic device includes: A memory, a processor, and a computer program stored on the memory and executable on the processor, wherein When the processor executes the program, it implements the method according to any one of claims 1 to 4.

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