Signal processing method and system, inverter control system and inverter

Abstract

The embodiment of the invention discloses a signal processing method and system, a control system of an inverter and the inverter. The method comprises the following steps: acquiring an output signal of the inverter; subtracting a preset reference signal from the output signal to obtain a clutter signal of the output signal; and processing the clutter signal based on a preset control algorithm to obtain a direct current component of the output signal. The method comprises the following steps: performing primary processing on an alternating current signal output by an inverter by adopting a preset reference signal with the same frequency and the same amplitude to obtain a clutter signal, and performing secondary processing on the clutter signal obtained after the primary processing by using a control algorithm obtained by performing discretization processing by using a transfer function. The technical problems that in the prior art, when a band elimination filter or a low-pass filter is used for conducting direct current component extraction on an alternating current signal output by an inverter, the response speed is low, and the extraction precision is low are solved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of signal processing technology, and in particular to a signal processing method and system, an inverter control system, and an inverter. Background Art

[0002] In the field of signal processing, the inverter is an important device that converts DC power into AC power and is widely used in various electronic devices. The output of the inverter contains both AC and DC components, of which the DC component may have adverse effects on the power grid or other equipment. Therefore, how to effectively extract the DC component in the inverter output and control it is an important technical challenge.

[0003] In the existing technology, a band-stop filter or a low-pass filter is usually used to extract the DC component in the inverter output. A band-stop filter is a filter that can filter out a specific frequency signal. By designing appropriate filter parameters, the DC component in the inverter output can be extracted. However, the control parameter of the band-stop filter is a fixed value, and the frequency of the AC component of the inverter output is not a fixed value, which will lead to low extraction accuracy. When the existing low-pass filter extracts the DC component of the inverter output, there is often a signal lag problem, which will lead to inaccuracy in controlling DC extraction and reduced response speed. Summary of the invention

[0004] The embodiments of the present invention provide a signal processing method, system, inverter control system and inverter, which solve the technical problems of low response speed and low extraction accuracy when using a band-stop filter or a low-pass filter to extract the DC component of the AC signal output by the inverter in the prior art.

[0005] An embodiment of the present invention provides a signal processing method, the signal processing method comprising:

[0006] Obtain the output signal of the inverter;

[0007] Subtracting the output signal from a preset reference signal to obtain a clutter signal of the output signal, wherein the preset reference signal has the same frequency and amplitude as the output signal;

[0008] The clutter signal is processed based on a preset control algorithm to obtain a DC component of the output signal, wherein the control algorithm is obtained by discretizing the signal using a transfer function.

[0009] Furthermore, the clutter signal is processed based on a preset control algorithm to obtain a DC component of the output signal, including:

[0010] The clutter signal is processed using the following preset control algorithm to extract the DC component of the output signal:

[0011]

[0012] Wherein, G is the DC component, K is the proportional coefficient, X=ω*Ts, ω is the angular frequency of the output signal, and Ts is the sampling time of the output signal.

[0013] Furthermore, the control algorithm of the adaptive band-stop filter controller is obtained by discretizing the transfer function; the transfer function is: TF = (K*ω*S 2 +K*ω 3 *S+K*ω 3 ) / (S 3 +2*ω*S 2 +2*ω 2 *S+ω 3 );

[0014] Wherein, TF is the transfer function, S is a complex variable in the complex frequency domain, S=2 / Ts*(z-1) / (z+1), and z is a variable of the discrete time system.

[0015] Furthermore, the value range of the proportionality coefficient K is 0.1-10.

[0016] Furthermore, the proportional coefficient K is 5.

[0017] An embodiment of the present invention further provides a signal processing system, wherein the signal processing system executes the signal processing method described in any of the above embodiments, and the signal processing system comprises:

[0018] A signal acquisition unit, used for acquiring an output signal of the inverter;

[0019] A signal extraction unit, configured to subtract the output signal from a preset reference signal to obtain a clutter signal of the output signal, wherein the preset reference signal has the same frequency and amplitude as the output signal;

[0020] The adaptive band-stop filter controller is used to process the clutter signal based on a preset control algorithm to obtain a DC component of the output signal, wherein the control algorithm is obtained by discretizing the transfer function.

[0021] Furthermore, the signal processing unit is specifically used for:

[0022] The clutter signal is processed using the following preset control algorithm to extract the DC component of the output signal:

[0023]

[0024] Wherein, G is the DC component, K is the proportional coefficient, X=ω*Ts, ω is the angular frequency of the output signal, and Ts is the sampling time of the output signal.

[0025] An embodiment of the present invention further provides an inverter control system, wherein the inverter control system processes an output signal of a target inverter by using the signal processing method described in any of the above embodiments.

[0026] An embodiment of the present invention further provides an inverter, which includes the inverter control system described in any of the above embodiments.

[0027] The embodiment of the present invention discloses a signal processing method, system, inverter control system and inverter, the method comprising: obtaining an output signal of the inverter; subtracting the output signal from a preset reference signal to obtain a clutter signal of the output signal, wherein the preset reference signal and the output signal have the same frequency and amplitude; processing the clutter signal based on a preset control algorithm to obtain a DC component of the output signal. The present invention processes the AC signal output by the inverter once using a preset reference signal with the same frequency and amplitude, and then processes the clutter signal obtained after the primary processing by a control algorithm obtained after discretization processing using a transfer function, thereby solving the technical problems of low response speed and low extraction accuracy when using a band-stop filter or a low-pass filter to extract the DC component of the AC signal output by the inverter in the prior art, and achieves the technical effect of improving the response speed and extraction accuracy of the DC component extraction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a flow chart of a signal processing method provided by an embodiment of the present invention;

[0029] Figure 2 is a waveform diagram of an AC signal containing a DC component and an extracted DC component provided by an embodiment of the present invention;

[0030] Figure 3 It is a structural diagram of a signal processing system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0032] It should be noted that the terms "first", "second", etc. in the specification, claims and drawings of the present invention are used to distinguish different objects, rather than to limit a specific order. The following embodiments of the present invention can be implemented separately, or in combination with each other, and the embodiments of the present invention do not impose specific limitations on this.

[0033] Figure 1 It is a flowchart of a signal processing method provided by an embodiment of the present invention.

[0034] like Figure 1 As shown, the signal processing method specifically includes the following steps:

[0035] S101, obtaining an output signal of an inverter.

[0036] Specifically, the inverter is usually used to convert DC power into AC power output, so the output signal of the inverter is an AC signal. However, the AC signal output by the inverter contains DC components and harmonics, among which the DC component may have adverse effects on the power grid or other equipment. Therefore, in order to ensure the safe operation of the power grid or other equipment, the output signal of the inverter can be obtained first, and then the DC component in the output signal can be extracted.

[0037] S102, subtracting the output signal from a preset reference signal to obtain a clutter signal of the output signal, wherein the preset reference signal and the output signal have the same frequency and amplitude.

[0038] Specifically, after obtaining the output signal of the inverter, it can be compared with a preset reference signal. The preset reference signal can be an AC signal with the same frequency and amplitude as the output signal. Generally speaking, the frequency range of the AC signal output by the inverter is 10-1000Hz, so the frequency range of the preset reference signal is also 10-1000Hz. The preset reference signal does not contain a DC component or a harmonic signal, so by comparing the output signal of the inverter with the preset reference signal, the clutter signal contained in the output signal can be obtained. The clutter signal usually includes harmonics in addition to the DC component.

[0039] In some optional embodiments, the preset reference signal may be a sine wave, a square wave or other desired waveform in addition to being equal to the frequency range of the output signal. This waveform should match the waveform that the inverter is designed to generate, so that any deviation can be accurately detected during the comparison between the preset reference signal and the output signal.

[0040] In some optional embodiments, environmental factors may affect the performance of the inverter. Therefore, the process of generating the preset reference signal and the process of comparing the preset reference signal with the output signal also need to consider environmental factors, such as temperature, humidity, pressure, electromagnetic interference, etc. In this embodiment, after multiple experimental verifications, it is determined that the optimal environmental parameters of the inverter in the above two stages are: temperature of 25°C, humidity of 50%, and pressure of 101.325kPa.

[0041] S103, processing the clutter signal based on a preset control algorithm to obtain a DC component of the output signal, wherein the control algorithm is obtained by discretizing the signal using a transfer function.

[0042] Specifically, the control algorithm obtained by discretizing the transfer function performs secondary processing on the clutter signal to obtain the DC component of the output signal. Exemplarily, the control algorithm can be integrated in an adaptive band-stop filter controller, and the adaptive band-stop filter controller can extract the DC component of the clutter signal by adaptively adjusting the control parameters according to the changing frequency of the AC signal, and filter out the harmonics in the clutter signal, so that the extraction accuracy of the DC component is higher.

[0043] It should be noted that the separated clutter signal can also be introduced into other adaptive devices capable of filtering harmonics to obtain a DC component, wherein other adaptive devices refer to devices using the control algorithm preset in this application. In this embodiment, only the adaptive band-stop filter controller is used as an example for explanation, but it does not mean that this process can only be implemented by the adaptive band-stop filter controller.

[0044] Figure 2 It is a waveform diagram of an AC signal containing a DC component and an extracted DC component provided by an embodiment of the present invention.

[0045] In some optional embodiments, Figure 2 Waveform a is an AC signal containing a DC component (i.e., the output signal of the inverter), waveform b is a DC component extracted by a conventional filter, such as a band-stop filter or a low-pass filter, and waveform c is a DC component extracted by using the signal processing method in this application and a preset control algorithm. Figure 2 It can be seen that although the conventional method can also extract the DC component, it still contains a certain AC component and has low accuracy. The DC component extracted by the signal processing method provided in the embodiment of the present invention is very smooth and has high accuracy.

[0046] The present invention processes the AC signal output by the inverter once by using a preset reference signal of the same frequency and amplitude, and then processes the clutter signal obtained after the primary processing by using a control algorithm obtained by discretization processing using a transfer function. This solves the technical problems of low response speed and low extraction accuracy when using a band-stop filter or a low-pass filter to extract the DC component of the AC signal output by the inverter in the prior art, and achieves the technical effect of improving the response speed and extraction accuracy of the DC component extraction.

[0047] Optionally, S103 processes the clutter signal based on a preset control algorithm to obtain a DC component of the output signal, specifically including:

[0048] The clutter signal is processed using the following preset control algorithm to extract the DC component of the output signal:

[0049]

[0050] Wherein, G is the DC component, K is the proportional coefficient, X=ω*Ts, ω is the angular frequency of the output signal, and Ts is the sampling time of the output signal.

[0051] Exemplarily, taking the control algorithm integrated in the adaptive band-stop filter controller as an example, it can be seen from the above formula that in the process of waveform processing of the adaptive band-stop filter controller, only the proportional coefficient K and the angular frequency ω are uncertain control parameters. The proportional coefficient K usually determines the response strength of the adaptive band-stop filter controller to the output signal, while the angular frequency ω determines the bandwidth of the adaptive band-stop filter controller. Therefore, in this embodiment, the characteristics of the input signal are analyzed through multiple experiments, including the amplitude, frequency and expected interference level of the signal, and the value range of the proportional coefficient K is determined to be 0.1-10. The proportional coefficient K within this range can make the adaptive band-stop filter controller respond faster and the extracted DC component has higher accuracy. When the proportional coefficient is set, the uncertain control parameters only include the angular frequency ω.

[0052] Preferably, the proportional coefficient K is set to 5. Experimental analysis shows that when the proportional coefficient is set to 5, the response speed and extraction accuracy are both optimal.

[0053] Optionally, the value range of the angular frequency ω is usually 10-1000, and its initial value can be set to 314. After many experiments, it is found that when the value of the angular frequency ω is 314, the DC component extracted by the method in this application is usually more accurate. Therefore, in order to improve the efficiency of the signal processing process, 314 can be used as the initial value of the angular frequency ω in this application.

[0054] In some optional embodiments, ω=2πf, where ω represents the angular frequency, 2π represents the proportionality factor, and f represents the frequency of the output signal. That is, the angular frequency ω is generally proportional to the frequency f of the output signal. Therefore, the angular frequency ω can be obtained by frequency conversion of the output signal of the inverter.

[0055] In some optional embodiments, when there is a slight fluctuation in the frequency of the output signal of the inverter, the adaptive band-stop filter controller can adaptively adjust the diagonal frequency ω based on the changing frequency of the output signal, thereby making the extracted DC component G more accurate.

[0056] In some optional embodiments, the preset control algorithm can be obtained by discretizing the transfer function. When the adaptive band-stop filter controller in the present application uses the control algorithm obtained by the above method, it can automatically adjust its parameters according to the characteristics of the input signal, that is, the adaptive band-stop filter controller in the present application can adapt to changes in the input signal, for example, when the interference frequency in the input signal changes, the adaptive band-stop filter controller can adjust its stopband frequency to maintain effective interference suppression.

[0057] In some optional embodiments, the transfer function can be expressed as: TF = (K * ω * S 2 +K*ω 3 *S+K*ω 3 ) / (S 3 +2*ω*S 2 +2*ω 2 *S+ω 3 );

[0058] Wherein, TF is the transfer function, S is a complex variable in the complex frequency domain, S=2 / Ts*(z-1) / (z+1), and z is a variable of the discrete time system.

[0059] In some optional embodiments, in the process of extracting the DC component by using a preset control algorithm, the environmental parameters of the environment in which the inverter is located may also be: temperature 25° C., humidity 50%, and pressure 101.325 kPa.

[0060] In some embodiments, the signal processing method can be verified by using the following equipment: the inverter model is HP-AH, the sensor model is Honeywell HI9300, and the computer model is Dell Inspiron 5593. The output signal of the inverter is obtained by using the sensor, and the output signal is input into the computer to extract the clutter signal and further extract the DC component by using the adaptive band-stop filter controller. The verification results are shown in Figure 2As shown in the figure, the software used in the computer includes Matlab and LabVIEW. Matlab is used for simulation and emulation, and LabVIEW is used for data acquisition and control.

[0061] In an embodiment of the present invention, by comparing the AC signal output by the inverter with a preset reference signal, a DC component error signal, i.e., the above-mentioned clutter signal, is obtained, and then the clutter signal is filtered by an adaptive band-stop filter controller using a control algorithm preset in the present application, so that a DC component with high precision can be extracted. A large amount of experiments and debugging are not required, which reduces the complexity and cost of technical implementation and improves the feasibility of technical implementation. Due to the use of an adaptive band-stop filter controller, the controller can automatically adjust parameters according to actual needs, thereby achieving effective extraction of the DC component and improving the extraction accuracy; it can not only improve the control accuracy and response speed, but also reduce the complexity and cost of technical implementation and improve the feasibility of technical implementation.

[0062] Figure 3 It is a structural diagram of a signal processing system provided by an embodiment of the present invention.

[0063] like Figure 3 As shown, the signal processing system specifically includes:

[0064] A signal acquisition unit 31, used to acquire an output signal of an inverter;

[0065] A signal extraction unit 32, configured to subtract the output signal from a preset reference signal to obtain a clutter signal of the output signal, wherein the preset reference signal has the same frequency and amplitude as the output signal;

[0066] The adaptive band-stop filter controller 33 is used to process the clutter signal based on a preset control algorithm to obtain a DC component of the output signal, wherein the control algorithm is obtained by discretizing the transfer function.

[0067] Optionally, the adaptive band-stop filter controller 33 is specifically used for:

[0068] The clutter signal is processed using the following preset control algorithm to extract the DC component of the output signal:

[0069]

[0070] Wherein, G is the DC component, K is the proportional coefficient, X=ω*Ts, ω is the angular frequency of the output signal, and Ts is the sampling time of the output signal.

[0071] The signal processing system provided by the embodiment of the present invention has the same technical features as the signal processing method provided by the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0072] An embodiment of the present invention further provides an inverter control system, which processes an output signal of a target inverter by using the signal processing method in any of the above embodiments.

[0073] The inverter control system provided by the embodiment of the present invention uses the signal processing method in the above embodiment, so the inverter control system provided by the embodiment of the present invention also has the beneficial effects described in the above embodiment, which will not be described again here.

[0074] An embodiment of the present invention further provides an inverter, which includes the inverter control system in any of the above embodiments.

[0075] The inverter provided by the embodiment of the present invention includes the inverter control system in the above embodiment, so the inverter provided by the embodiment of the present invention also has the beneficial effects described in the above embodiment, which will not be described in detail here.

[0076] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0077] Finally, it should be noted that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A signal processing method, characterized in that: The signal processing method comprises: Obtain the output signal of the inverter; Subtracting the output signal from a preset reference signal to obtain a clutter signal of the output signal, wherein the preset reference signal has the same frequency and amplitude as the output signal; The clutter signal is processed based on a preset control algorithm to obtain a DC component of the output signal, wherein the control algorithm is obtained by discretizing the signal using a transfer function.

2. The signal processing method according to claim 1, characterized in that: Processing the clutter signal based on a preset control algorithm to obtain a DC component of the output signal includes: The clutter signal is processed using the following preset control algorithm to extract the DC component of the output signal: Wherein, G is the DC component, K is the proportional coefficient, X=ω*Ts, ω is the angular frequency of the output signal, and Ts is the sampling time of the output signal.

3. The signal processing method according to claim 1, characterized in that: The transfer function is: TF = (K * ω * S 2 +K*ω 3 *S+K*ω 3 ) / (S 3 +2*ω*S 2 +2*ω 2 *S+ω 3 ); Wherein, TF is the transfer function, S is a complex variable in the complex frequency domain, S=2 / Ts*(z-1) / (z+1), and z is a variable of the discrete time system.

4. The signal processing method according to claim 2, characterized in that: The value range of the proportionality coefficient K is 0.1-10.

5. The signal processing method according to claim 2, characterized in that: The proportionality coefficient K is 5.

6. A signal processing system, characterized in that: The signal processing system executes the signal processing method according to any one of claims 1 to 5, and the signal processing system comprises: A signal acquisition unit, used for acquiring an output signal of the inverter; A signal extraction unit, configured to subtract the output signal from a preset reference signal to obtain a clutter signal of the output signal, wherein the preset reference signal has the same frequency and amplitude as the output signal; The adaptive band-stop filter controller is used to process the clutter signal based on a preset control algorithm to obtain a DC component of the output signal, wherein the control algorithm is obtained by discretizing the transfer function.

7. The signal processing system according to claim 6, characterized in that The adaptive band-stop filter controller is specifically used for: The clutter signal is processed using the following preset control algorithm to extract the DC component of the output signal: Wherein, G is the DC component, K is the proportional coefficient, X=ω*Ts, ω is the angular frequency of the output signal, and Ts is the sampling time of the output signal.

8. An inverter control system, characterized in that: The inverter control system processes the output signal of the target inverter by using the signal processing method described in any one of claims 1 to 5.

9. An inverter, characterized in that: The inverter includes the inverter control system described in claim 8 above.

Images