A Si / SiC topology parallel inverter harmonic suppression method based on multi-harmonic observation and feedforward compensation

Abstract

The application discloses a Si / SiC topology parallel inverter harmonic suppression method based on multi-harmonic observation and feedforward compensation, and relates to the technical field of power electronics. The method comprises the following steps: monitoring each harmonic signal output by a Si IGBT inverter of a Si / SiC topology parallel inverter in real time, and determining the amplitude and phase of each harmonic signal; the Si / SiC topology parallel inverter is a parallel structure of a Si IGBT inverter and a SiC MOSFET inverter; according to the amplitude and the phase, an adjusted current compensation signal is generated based on a gain scheduling mechanism; the adjusted current compensation signal is a current compensation signal that is equal in amplitude and opposite in direction to a harmonic signal of the SiC MOSFET inverter; and the harmonic signal output by the SiC MOSFET inverter is suppressed according to the adjusted current compensation signal. The application can improve the harmonic suppression capability and power quality, and is suitable for high-power power systems and application occasions with strict requirements on power quality.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a harmonic suppression method for Si / SiC topology parallel inverters based on multi-harmonic observation and feedforward compensation. Background Art

[0002] With the transformation of the global energy mix and the rapid development of renewable energy, particularly the widespread use of solar and wind power, power system operations are facing increasing challenges. In particular, the intermittent and fluctuating nature of renewable energy has led to increasingly stringent requirements for power quality. High-frequency harmonics, a common form of power pollution in power systems, not only affect the operating efficiency and safety of equipment but can also cause grid instability, equipment damage, and even failure. Therefore, accurately suppressing harmonics in inverter output without sacrificing system efficiency has become a key technical challenge in modern power systems.

[0003] Currently, inverters are widely used in distributed energy systems, microgrids, energy storage systems, and other fields. In large-scale access, inverter harmonics are particularly prominent. While topologies using wide-bandgap semiconductor materials such as silicon (Si) and silicon carbide (SiC) have become mainstream solutions, and their parallel use effectively improves inverter efficiency and reduces switching losses, they still cannot completely solve the problem of suppressing high-frequency harmonics. Si IGBT inverters offer high efficiency at low frequencies, but their ability to suppress high-frequency harmonics is weak at high frequencies and under dynamic load fluctuations. While SiC MOSFET inverters exhibit significant advantages at high frequencies, their ability to suppress low- and medium-frequency harmonics is relatively inadequate. Furthermore, the real-time and stable harmonic compensation in dynamic environments with sudden load changes remains a significant challenge. Therefore, although the parallel structure of Si IGBT and SiC MOSFET inverters has made breakthroughs in improving the overall performance of the system, its harmonic suppression capability under different load and frequency conditions still cannot meet the increasingly stringent power quality requirements of high-power systems. It is urgent to further optimize its harmonic suppression and dynamic compensation capabilities to meet the grid operation needs after the large-scale integration of new energy. Summary of the Invention

[0004] The purpose of this application is to provide a harmonic suppression method for Si / SiC topology parallel inverters based on multi-harmonic observation and feedforward compensation, so as to solve the problem that the inverter output harmonic suppression capability in the prior art is poor and cannot meet the increasingly stringent requirements of high-power systems for power quality.

[0005] To achieve the above objectives, this application provides the following solutions.

[0006] The present application provides a harmonic suppression method for a Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation, comprising the following steps.

[0007] Real-time monitoring of each harmonic signal output by the Si IGBT inverter in the Si / SiC topology parallel inverter determines the amplitude and phase of each harmonic signal; the Si / SiC topology parallel inverter is a parallel structure of a Si IGBT inverter and a SiC MOSFET inverter.

[0008] According to the amplitude and the phase, based on a gain scheduling mechanism, an adjusted current compensation signal is generated; the adjusted current compensation signal is a current compensation signal with equal amplitude and opposite direction to the harmonic signal of the SiC MOSFET inverter.

[0009] The harmonic signal output by the SiC MOSFET inverter is suppressed according to the adjusted current compensation signal.

[0010] According to the specific embodiments provided in this application, this application discloses the following technical effects: This application determines the amplitude and phase of each harmonic signal output by the SiIGBT inverter, and based on the gain scheduling mechanism, generates an adjusted current compensation signal. The adjusted current compensation signal is a current compensation signal with equal amplitude and opposite direction to the harmonic signal of the SiC MOSFET inverter. The current compensation signal can accurately and in real time suppress the harmonic signal output by the SiC MOSFET inverter, thereby improving the power quality. In addition, based on the gain scheduling mechanism, it can ensure that efficient harmonic suppression performance can still be maintained in the case of load mutation or overload. It is suitable for high-power power systems and applications with strict requirements on power quality, improves the resonance pollution problem of the inverter output, and further improves the power quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0012] Figure 1 A flow chart of a harmonic suppression method for Si / SiC topology parallel inverters based on multi-harmonic observation and feedforward compensation is provided in one embodiment of the present application.

[0013] Figure 2 This is a block diagram of a harmonic suppression method for Si / SiC topology parallel inverters based on multi-harmonic observation and feedforward compensation provided in one embodiment of the present application.

[0014] Figure 3A flowchart of another harmonic suppression method for Si / SiC topology parallel inverters based on multi-harmonic observation and feedforward compensation is provided in an embodiment of the present application. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0016] The present application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0017] The embodiment of the present application provides a method for harmonic suppression of Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation. The method is executed by a computer device, which can be executed by a computer device such as a terminal or a server alone, or by a terminal and a server together. In the embodiment of the present application, Figure 1-Figure 2 As shown, Figure 2 Where g1 represents the driving signal of inverter 1 (Si IGBT inverter), g2 represents the driving signal of inverter 2 (SiC MOSFET inverter), and the method includes the following steps.

[0018] S1: Real-time monitoring of each harmonic signal output by the Si IGBT inverter in the Si / SiC topology parallel inverter to determine the amplitude and phase of each harmonic signal; the Si / SiC topology parallel inverter is a parallel structure of a Si IGBT inverter and a SiC MOSFET inverter.

[0019] S2: Generate an adjusted current compensation signal based on the amplitude and the phase and a gain scheduling mechanism; the adjusted current compensation signal is a current compensation signal with equal amplitude and opposite direction to the harmonic signal of the SiC MOSFET inverter.

[0020] S3: Suppress the harmonic signal output by the SiC MOSFET inverter according to the adjusted current compensation signal.

[0021] In an exemplary embodiment, S1 specifically includes: based on a multi-harmonic observation module, using an improved Kalman filter algorithm, real-time monitoring of each harmonic signal output by the Si IGBT inverter in the Si / SiC topology parallel inverter, and estimating the amplitude of each harmonic signal.

[0022] An adaptive phase-locked loop (PLL) algorithm is used to synchronize the frequency and phase of the grid signal, and the phase of each harmonic signal is estimated based on the frequency and phase of the grid.

[0023] In an exemplary embodiment, based on the multi-harmonic observation module, an improved Kalman filter algorithm is used to monitor the harmonic signals output by the Si IGBT inverter in the Si / SiC topology parallel inverter in real time and estimate the amplitude of each harmonic signal, specifically including: using Estimate the amplitude of each harmonic signal; where, is the estimated value of the amplitude of the kth harmonic; is the estimated value of the amplitude of the k-1th harmonic; is the measurement matrix; is the Kalman gain, ; Forecast error covariance S Describes the reliability of the system state estimation, which reflects the estimation error of the system when making predictions; S k is the prediction error covariance matrix at time k, which represents the prediction error of the system state; S k-1 is the prediction error covariance matrix at time k-1, which represents the prediction error at the previous moment; F is the state transition matrix, which describes the change of system state from time k-1 to time k; Q is the process noise covariance matrix, which represents the noise in the system dynamic process and is usually estimated by the system model and external environment changes. H Describes how the system state is mapped to the measurement space, representing the linear relationship from the system state to the observation value. For each moment k, the measurement matrix H Is a constant matrix, that is, the state variables of the system x k To the measured variable z k relationship; z k is the measured value at time k, i.e., the measured variable, which represents the actual observation signal obtained from the sensor; x k The system state at time k represents the state variables of the system; v k For measurement noise, it is usually assumed to be Gaussian noise with zero mean. Measurement noise covariance R Describes the noise intensity in the measurement process, which is usually assumed to be a constant. It reflects the measurement error caused by sensor accuracy limitations or other external interference; T is the transposed matrix.

[0024] In an exemplary embodiment, an adaptive phase-locked loop algorithm is used to synchronize the frequency and phase of the power grid signal, and the phase of each harmonic signal is estimated according to the frequency and phase of the power grid, including: using Estimate the phase of each harmonic signal; where, is the grid phase at time t; is the reference frequency; is the gain parameter; is the phase error signal, which represents the phase difference between the grid voltage signal and the reference voltage signal; is the grid input voltage signal, which includes amplitude and phase signals. is the reference voltage signal; arg() is the complex argument extraction function, which is used to obtain the complex phase angle.

[0025] In an exemplary embodiment, S2 specifically includes: generating, based on the feedforward compensation module and according to the amplitude and phase, a current compensation signal with equal amplitude and opposite direction to each harmonic signal of the Si IGBT inverter.

[0026] Based on a gain scheduling mechanism, the gain of the current compensation signal is dynamically adjusted according to the load power variation.

[0027] An adjusted current compensation signal is generated according to the adjusted gain.

[0028] In an exemplary embodiment, based on the feedforward compensation module, a current compensation signal having equal amplitude and opposite direction to each harmonic signal of the SiIGBT inverter is generated according to the amplitude and phase, specifically comprising: using , generating a current compensation signal with equal amplitude and opposite direction to each harmonic signal of the Si IGBT inverter; wherein, It is a current compensation signal with equal amplitude and opposite direction to each harmonic signal of Si IGBT inverter; For the n The current amplitude of the subharmonics; For the n Phase of subharmonic signal; is the reference frequency; N is the total number of harmonic signals.

[0029] In an exemplary embodiment, based on a gain scheduling mechanism, the gain of the current compensation signal is dynamically adjusted according to the load power change, which also includes: during the gain adjustment process, the load power change is monitored in real time to determine that the load power change is within a variation range; the load power change within the variation range enables the current compensation signal to still work effectively under load fluctuations or mutations.

[0030] In an exemplary embodiment, based on the gain scheduling mechanism, the gain of the current compensation signal is dynamically adjusted according to the load power change, specifically including: using Adjusting the gain of the current compensation signal; wherein, G ( t ) is the gain after adjustment at time t; G 0 is the initial gain; α is the adjustment coefficient; Δ P is the load power change.

[0031] In an exemplary embodiment, generating an adjusted current compensation signal according to the adjusted gain specifically includes: using Generate an adjusted current compensation signal; wherein, is the adjusted current compensation signal.

[0032] In an exemplary embodiment, before S1, the process further includes: applying a driving signal to the Si IGBT inverter and the SiC MOSFET inverter respectively. Figure 2 As shown, the drive signal g1 is generated by the voltage control loop and the current control loop in the inverter 1 control link, and the drive signal g2 is generated by the inverter 2 control link, wherein the inverter 2 control link includes a multi-harmonic observation module, a feedforward compensation module, a gain scheduling mechanism and a current control loop.

[0033] This application is based on the parallel structure of Si IGBT inverter and SiC MOSFET inverter, combined with multi-harmonic observation technology and feedforward compensation method, to accurately and in real time suppress multiple harmonics in the inverter output and improve power quality.

[0034] like Figure 2 As shown, the harmonic suppression method shown in this application can be applied to the stability control of grid-type power systems based on multi-modal collaboration. The multi-harmonic observation module adopts an improved Kalman filter algorithm and an adaptive phase-locked loop algorithm to obtain the amplitude and phase of each harmonic in real time, and provide feedback signals for the feedforward compensation module. The feedforward compensation module generates a compensation signal with equal amplitude and opposite direction to the harmonic according to the harmonic amplitude and phase, which significantly improves the harmonic suppression effect. The gain scheduling mechanism dynamically adjusts the compensation signal gain according to the load change to ensure that the system can maintain efficient harmonic suppression performance in the case of load mutation or overload.

[0035] This application is suitable for high-power power systems and applications with strict requirements on power quality. It can significantly improve the harmonic pollution output by the inverter and improve the power quality.

[0036] In an exemplary embodiment, the present application provides a method for suppressing harmonics in a Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation. Figure 3shown.

[0037] Step 1: First, the multi-harmonic observation module monitors the harmonic signals in the power system in real time. This module uses an improved Kalman filter algorithm to dynamically estimate the amplitude and phase of each harmonic signal in the power system. The Kalman filter optimizes the prediction error of the harmonic signal and updates the amplitude and phase estimates of each harmonic signal in real time, ensuring that the system can accurately track harmonic changes.

[0038] Step 2: Next, an adaptive phase-locked loop (PLL) algorithm synchronizes the grid's frequency and phase. This algorithm calculates the phase difference between the grid signal and a reference signal and adjusts the frequency to synchronize them. This process ensures the accuracy of the multi-harmonic observation module, enabling subsequent harmonic signal estimation to obtain precise phase information.

[0039] Step 3: After obtaining the precise harmonic amplitude and phase, the feedforward compensation module uses this information to generate current compensation signals with equal and opposite amplitudes to the harmonics. The compensation signals are generated by inverting the amplitude and phase of each harmonic signal. These inverted current signals are used to suppress harmonics in the inverter output, ensuring that the system's output power quality meets standard requirements.

[0040] Step 4: To address load variations and overload conditions, the gain scheduling mechanism adjusts the compensation signal gain in real time based on load power changes. When the system load undergoes a sudden change, the gain scheduling mechanism adjusts the compensation signal gain to ensure that the compensation signal remains efficient under varying load conditions. This adjustment process ensures that the system maintains effective harmonic mitigation performance despite varying load conditions.

[0041] Step 5: Finally, the gain-scheduled, optimized reverse compensation current signal is output to the system, adjusting the inverter's output current in real time, effectively suppressing harmonic pollution. The entire system continuously adjusts based on real-time load changes and harmonic characteristics, ensuring stable inverter output current and improving power quality. This process maintains system efficiency and stability in complex and dynamic load environments.

[0042] This application is based on the parallel structure of Si IGBT inverter and SiC MOSFET inverter, taking advantage of the complementary advantages of the two devices in different frequency bands to achieve accurate observation and real-time compensation of multiple harmonics in the inverter output, significantly improving the overall performance and stability of the inverter system.

[0043] First, this application introduces a multi-harmonic observation module based on an improved Kalman filter algorithm, which can monitor and accurately estimate the harmonic amplitude and phase in the power supply system in real time. Through this module, the system can dynamically identify the harmonics in the inverter output and provide real-time feedback for the subsequent compensation module. The Kalman filter algorithm is adaptive and can optimize the estimated value in the presence of noise or interference in the harmonic signal, thereby ensuring the accuracy and stability of the harmonic observation. In addition, by combining the adaptive phase-locked loop algorithm, this application can synchronize the frequency and phase of the power grid, further improve the accuracy of the multi-harmonic observation module, and ensure accurate tracking of the harmonic signal under complex dynamic conditions.

[0044] Secondly, the feedforward compensation module of the present application can generate a current compensation signal with equal amplitude and opposite direction to the harmonics based on the obtained harmonic amplitude and phase information. These compensation signals are output through the inverter, thereby effectively offsetting the impact of harmonics on the power system. Feedforward compensation ensures that the amplitude of the harmonics is reduced to a minimum by precisely adjusting the amplitude and phase of the compensation signal, thereby achieving dual suppression of high-frequency harmonics and low-frequency harmonics. Unlike traditional passive filtering technology, the feedforward compensation method of the present application can respond to system changes in real time without the need for additional filtering components, thereby improving the dynamic response speed and efficiency of the system.

[0045] To ensure that the system can maintain efficient harmonic suppression performance in the event of a sudden load change or overload, this application also introduces a gain scheduling mechanism. The gain scheduling mechanism dynamically adjusts the gain of the compensation signal to adapt to changes in load power. The gain adjustment is based on the real-time monitored load power change to ensure that the compensation signal can still work effectively in the event of load fluctuations or sudden changes. Through this mechanism, this application can ensure that a stable harmonic suppression effect can be maintained even when grid conditions or loads change frequently.

[0046] The harmonic suppression method of the Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation provided in this application has the following advantages: on the one hand, through the parallel structure of Si IGBT and SiC MOSFET, the advantages of both in different frequency bands are fully utilized to improve the overall power conversion efficiency of the system; on the other hand, through the combination of Kalman filtering and adaptive phase-locked loop algorithm, the high accuracy and high real-time performance of harmonic observation are ensured; furthermore, the feedforward compensation module can achieve precise harmonic suppression, avoiding the problems of poor frequency adaptability and compensation lag faced by traditional filters; finally, the introduction of the gain scheduling mechanism ensures the efficient operation of the system under load fluctuations or sudden changes. These innovations enable this application to operate stably and effectively improve the power quality under variable and complex working conditions, and has broad application prospects, especially suitable for harmonic suppression tasks in high-power inverter systems and new energy power generation systems.

[0047] Any technical features in the above embodiments can be combined, and for the sake of brevity, not all possible combinations are described above, however, it should be understood that the application encompasses all possible combinations of the technical features described above.

[0048] The principles and implementation manners of the present application are described herein by using specific examples, and the above embodiments are only used to help understand the method of the present application and its core idea; meanwhile, according to the idea of the present application, the specific implementation manners and application scopes will be changed by those skilled in the art. In conclusion, the content of the present specification should not be understood as a limitation of the present application.

Claims

1. A harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation, characterized in that: include: Real-time monitoring of the harmonic signals output by the Si IGBT inverter in the Si / SiC topology parallel inverter, and determination of the amplitude and phase of each harmonic signal; The Si / SiC topology parallel inverter is a parallel structure of a Si IGBT inverter and a SiC MOSFET inverter; Generating an adjusted current compensation signal according to the amplitude and the phase based on a gain scheduling mechanism specifically includes: Based on the feedforward compensation module, a current compensation signal with equal amplitude and opposite direction to each harmonic signal of the Si IGBT inverter is generated according to the amplitude and phase; Based on a gain scheduling mechanism, dynamically adjusting the gain of the current compensation signal according to the load power change; Generate an adjusted current compensation signal according to the adjusted gain; the adjusted current compensation signal is a current compensation signal with equal amplitude and opposite direction to the harmonic signal of the SiCMOSFET inverter; The harmonic signal output by the SiC MOSFET inverter is suppressed according to the adjusted current compensation signal.

2. The harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation according to claim 1 is characterized in that: Real-time monitoring of the harmonic signals output by the Si IGBT inverter in the Si / SiC topology parallel inverter, and determination of the amplitude and phase of each harmonic signal, including: Based on the multi-harmonic observation module, an improved Kalman filter algorithm is used to monitor the harmonic signals output by the Si IGBT inverter in the Si / SiC topology parallel inverter in real time and estimate the amplitude of each harmonic signal. An adaptive phase-locked loop algorithm is used to synchronize the frequency and phase of the power grid signal, and the phase of each harmonic signal is estimated based on the frequency and phase of the power grid.

3. The harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation according to claim 2 is characterized in that: Based on the multi-harmonic observation module, an improved Kalman filter algorithm is used to monitor the harmonic signals output by the Si IGBT inverter in the Si / SiC topology parallel inverter in real time and estimate the amplitude of each harmonic signal. Specifically, the following are performed: use Estimate the amplitude of each harmonic signal; where, is the estimated value of the amplitude of the kth harmonic; is the estimated value of the amplitude of the k-1th harmonic; is the Kalman gain; is the measured variable; is the measurement matrix.

4. The harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation according to claim 2 is characterized in that: Adaptive phase-locked loop algorithm is used to synchronize the frequency and phase of the grid signal, and the phase of each harmonic signal is estimated based on the frequency and phase of the grid, including: use Estimate the phase of each harmonic signal; where, is the grid phase at time t; is the reference frequency; is the gain parameter; is the phase error signal at time t, which represents the phase difference between the grid voltage signal and the reference voltage signal; is the grid input voltage signal, which includes amplitude and phase signals. is the reference voltage signal; arg() is the complex argument extraction function.

5. The harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation according to claim 1 is characterized in that: Based on the feedforward compensation module, a current compensation signal with equal amplitude and opposite direction to each harmonic signal of the Si IGBT inverter is generated according to the amplitude and phase, specifically including: use , generating a current compensation signal with equal amplitude and opposite direction to each harmonic signal of the Si IGBT inverter; wherein, is the current compensation signal with equal amplitude and opposite direction to the harmonic signals of the Si IGBT inverter at time t; For the n Subharmonic current amplitude; For the n Phase of subharmonic signal; is the reference frequency; N is the total number of harmonic signals.

6. The harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation according to claim 1 is characterized in that: Based on the gain scheduling mechanism, the gain of the current compensation signal is dynamically adjusted according to the load power change, which also includes: During the gain adjustment process, the load power variation is monitored in real time to determine if the load power variation is within a variation range; the load power variation within the variation range enables the current compensation signal to still work effectively under load fluctuations or mutations.

7. The harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation according to claim 5, characterized in that: Based on the gain scheduling mechanism, the gain of the current compensation signal is dynamically adjusted according to the load power change, specifically including: use Adjusting the gain of the current compensation signal; wherein, G ( t ) is the gain after adjustment at time t; G 0 is the initial gain; α is the adjustment coefficient; Δ P is the load power variation.

8. The harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation according to claim 7, characterized in that: Generate an adjusted current compensation signal according to the adjusted gain, specifically including: use Generate an adjusted current compensation signal; wherein, is the adjusted current compensation signal.

9. The harmonic suppression method for Si / SiC topology parallel inverter based on multi-harmonic observation and feedforward compensation according to claim 1, characterized in that: Real-time monitoring of the harmonic signals output by the Si IGBT inverter in the Si / SiC topology parallel inverter to determine the amplitude and phase of each harmonic signal. Previously, this also included: A driving signal is applied to each of the Si IGBT inverter and the SiC MOSFET inverter.

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