Composite current tracking compensation method and device and nonvolatile storage medium

Abstract

The invention discloses a composite current tracking compensation method and device and a nonvolatile storage medium. The method comprises the following steps: detecting the current of a load side of a power grid through a current transformer to obtain a load current signal; inputting the load current signal into a digital signal processor in the parallel active power filter to obtain an instruction reference value; based on the instruction reference value, a composite controller and a pulse width modulator are used for generating a pulse width modulation signal, and the composite controller is composed of a proportional-integral controller and a repetitive controller; the pulse width modulation signal is used for controlling a silicon carbide semiconductor switch to generate target compensation current, and the target compensation current is used for controlling harmonic waves generated in a power grid. According to the invention, the technical problem that the tracking compensation control effect of the harmonic current is poor due to the fact that only the PI controller is utilized to generate the PWM signal in the tracking compensation control process of the harmonic in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of electric power, and in particular to a composite current tracking compensation method, device and non-volatile storage medium. Background Art

[0002] At present, harmonic elimination equipment mainly uses PI control, hysteresis control, proportional resonance control, predictive control and other methods to track and compensate harmonic currents. However, with the continuous development of power systems, system harmonics are distributed in a diversified and complex manner. A single traditional control method is difficult to cope with the variable frequency amplitude changes, and the real-time, flexibility and adaptability of the control are relatively low.

[0003] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0004] The embodiments of the present invention provide a composite current tracking compensation method, device and non-volatile storage medium to at least solve the technical problem in the related art that in the process of harmonic tracking compensation control, only a PI controller is used to generate a PWM signal, resulting in poor tracking compensation control effect of harmonic current.

[0005] According to one aspect of an embodiment of the present invention, a composite current tracking compensation method is provided, comprising: detecting the current on the load side of a power grid through a current transformer to obtain a load current signal; inputting the load current signal into a digital signal processor in a parallel active power filter to obtain an instruction reference value, wherein the instruction reference value comprises: the magnitude and phase information of the compensation current to be generated; based on the instruction reference value, generating a pulse width modulation signal using a composite controller and a pulse width modulator, wherein the composite controller is composed of a proportional-integral controller and a repetitive controller; and controlling a silicon carbide semiconductor switch using the pulse width modulation signal to generate a target compensation current, wherein the target compensation current is used to control harmonics generated in the power grid, and the silicon carbide semiconductor switch comprises: a semiconductor switch made of silicon carbide material.

[0006] Furthermore, based on the instruction reference value, a pulse width modulated signal is generated using a composite controller and a pulse width modulator, including: determining the harmonic current in the load current signal to obtain a harmonic current signal; inputting the harmonic current signal and the instruction reference value into the composite controller, and outputting a pre-compensation current reference value, wherein the pre-compensation current reference value includes: reference data of the compensation current to be generated; inputting the pre-compensation current reference value into the pulse width modulator, and outputting the pulse width modulated signal.

[0007] Furthermore, after using the pulse width modulation signal to control the silicon carbide semiconductor switch to generate the target compensation current, it also includes: using an inductor to inject the target compensation current into the power grid; after injecting the target compensation current into the power grid, detecting the current of the power grid to obtain a detection result, wherein the detection result includes: the component of the harmonic current in the power grid.

[0008] Furthermore, after using the pulse width modulation signal to control the silicon carbide semiconductor switch to generate a target compensation current, it also includes: comparing the target compensation current and the instruction reference value to obtain a second comparison result; based on the comparison result, determining whether to adjust the compensation strategy, wherein the compensation strategy includes: a control strategy for controlling the harmonics generated by the power grid.

[0009] Furthermore, the load current signal is input into a digital signal processor in a parallel active power filter to obtain a command reference value, including: inputting the load current signal into a digital signal processor in a parallel active power filter, and using the digital signal processor to analyze the load current signal to obtain an analysis result, wherein the analysis result at least includes: a harmonic component in the load current signal; and generating the command reference value based on the analysis result.

[0010] Furthermore, based on the pulse width modulation signal, the silicon carbide semiconductor switch is controlled to switch according to a preset switching frequency to obtain the target compensation current, wherein the preset switching frequency is used to control the switching frequency of the silicon carbide semiconductor switch.

[0011] Furthermore, the current transformer is deployed between the power grid and the load side of the power grid, and the current on the load side of the power grid is detected by the current transformer to obtain a load current signal, including: using the primary side of the current transformer and the secondary side of the current transformer to collect the current on the load side to obtain an analog current signal; converting the analog current signal into a digital signal to obtain the load current signal.

[0012] According to another aspect of an embodiment of the present invention, a composite current tracking compensation device is also provided, comprising: a detection unit, used to detect the current on the load side of the power grid through a current transformer to obtain a load current signal; a processing unit, used to input the load current signal into a digital signal processor in a parallel active power filter to obtain an instruction reference value, wherein the instruction reference value includes: the magnitude and phase information of the compensation current to be generated; a first generation unit, used to generate a pulse width modulation signal based on the instruction reference value using a composite controller and a pulse width modulator, wherein the composite controller is composed of a proportional-integral controller and a repetitive controller; a second generation unit, used to control a silicon carbide semiconductor switch to generate a target compensation current using the pulse width modulation signal, wherein the target compensation current is used to control the harmonics generated in the power grid, and the silicon carbide semiconductor switch includes: a semiconductor switch made of silicon carbide material.

[0013] Furthermore, the first generating unit includes: a determining subunit, used to determine the harmonic current in the load current signal to obtain a harmonic current signal; a first processing subunit, used to input the harmonic current signal and the instruction reference value into the composite controller, and output a pre-compensation current reference value, wherein the pre-compensation current reference value includes: reference data of the compensation current to be generated; and a second processing subunit, used to input the pre-compensation current reference value into the pulse width modulator, and output the pulse width modulated signal.

[0014] Furthermore, the composite current tracking compensation device includes: an injection unit, which is used to inject the target compensation current into the power grid using an inductor after using the pulse width modulation signal to control the silicon carbide semiconductor switch to generate a target compensation current; a detection unit, which is used to detect the current of the power grid after injecting the target compensation current into the power grid to obtain a detection result, wherein the detection result includes: a component of the harmonic current in the power grid.

[0015] Furthermore, the composite current tracking compensation device also includes: a comparison unit, which is used to compare the target compensation current and the instruction reference value to obtain a second comparison result after using the pulse width modulation signal to control the silicon carbide semiconductor switch to generate the target compensation current; a determination unit, which is used to determine whether to adjust the compensation strategy based on the comparison result, wherein the compensation strategy includes: a control strategy for controlling the harmonics generated by the power grid.

[0016] Furthermore, the processing unit includes: a third processing sub-unit, used to input the load current signal into a digital signal processor in the parallel active power filter, and use the digital signal processor to analyze the load current signal to obtain an analysis result, wherein the analysis result at least includes: a harmonic component in the load current signal; a generating sub-unit, used to generate the instruction reference value based on the analysis result.

[0017] Furthermore, the second generating unit includes: a control subunit, which controls the switching of the silicon carbide semiconductor switch according to a preset switching frequency based on the pulse width modulation signal to obtain the target compensation current, wherein the preset switching frequency is used to control the switching frequency of the silicon carbide semiconductor switch.

[0018] Furthermore, the current transformer is deployed between the power grid and the load side of the power grid, and the detection unit includes: a collection subunit, used to use the primary side of the current transformer and the secondary side of the current transformer to collect the current on the load side to obtain an analog current signal; a conversion subunit, used to convert the analog current signal into a digital signal to obtain the load current signal.

[0019] According to another aspect of an embodiment of the present invention, there is also provided an electronic device, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to perform a composite current tracking compensation method by executing the executable instructions.

[0020] According to another aspect of an embodiment of the present invention, a non-volatile storage medium is provided, wherein the non-volatile storage medium stores a program, wherein when the program is executed, the device where the non-volatile storage medium is located is controlled to execute a composite current tracking compensation method.

[0021] In the present invention, the current on the load side of the power grid is detected by a current transformer to obtain a load current signal; the load current signal is input into a digital signal processor in a parallel active power filter to obtain an instruction reference value, wherein the instruction reference value includes: the magnitude and phase information of the compensation current to be generated; based on the instruction reference value, a pulse width modulation signal is generated by a composite controller and a pulse width modulator, wherein the composite controller is composed of a proportional integral controller and a repetitive controller; the pulse width modulation signal is used to control the silicon carbide semiconductor switch to generate a target compensation current, wherein the target compensation current is used to control the harmonics generated in the power grid, and the silicon carbide semiconductor switch includes: a semiconductor switch made of silicon carbide material. This solves the technical problem in the related art that in the process of tracking and compensating harmonics, only a PI controller is used to generate a PWM signal, and the tracking and compensating control effect of harmonic current is poor.

[0022] In the present invention, a composite controller and a pulse width modulator are used to obtain a pulse width modulated signal, and then the pulse width modulated signal is used to generate a compensation current to control the harmonics in the power grid, thereby avoiding the situation where a single traditional control method is difficult to cope with variable frequency amplitude changes, thereby achieving the technical effect of improving the accuracy of harmonic current tracking compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 is a flow chart of an optional composite current tracking compensation method according to an embodiment of the present invention;

[0025] Figure 2 is a schematic diagram of an optional composite controller according to an embodiment of the present invention;

[0026] Figure 3 is a schematic diagram of an optional composite current tracking compensation device according to an embodiment of the present invention;

[0027] Figure 4 is a schematic diagram of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0030] It should be noted that the user information (including but not limited to user device information, user personal information, etc.), collected information and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, storage, use, processing, transmission, provision, disclosure and application of the relevant data comply with the relevant laws, regulations and standards of the relevant regions, take necessary confidentiality measures, do not violate public order and good morals, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0031] Embodiment 1

[0032] According to an embodiment of the present invention, a method embodiment of an optional composite current tracking compensation method is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0033] Figure 1 is a flow chart of an optional composite current tracking compensation method according to an embodiment of the present invention, such as Figure 1 As shown, the method comprises the following steps:

[0034] Step S101, detecting the current on the load side of the power grid through a current transformer to obtain a load current signal.

[0035] The above-mentioned load current signal can be used to represent the current on the load side of the power grid. In this embodiment, the current on the load side of the power grid can be collected by a current transformer to obtain the load current signal.

[0036] Step S102: input the load current signal into a digital signal processor in the parallel active power filter to obtain a command reference value, wherein the command reference value includes: the magnitude and phase information of the compensation current to be generated.

[0037] The above-mentioned compensation current to be generated can be used to suppress harmonics in the power grid. In this embodiment, the load current signal can be input into a digital signal processor in the parallel active power filter, and the above-mentioned instruction reference value can be generated by the digital signal processor.

[0038] For example, the three-phase current (iLa, iLb, iLc) on the load side is monitored in real time through an external current transformer. These current signals are sent to the digital signal processor (DSP) inside the APF (corresponding to the parallel active power filter).

[0039] Step S103: Based on the command reference value, a pulse width modulation signal is generated by using a compound controller and a pulse width modulator, wherein the compound controller is composed of a proportional integral controller and a repetitive controller.

[0040] In this embodiment, the command reference value and the harmonic current in the detected load-side current signal can be input into a composite current tracking compensation controller (corresponding to a composite controller), and a pre-compensation current reference value can be output and input into a PWM modulator (corresponding to a pulse width modulator) to obtain a pulse width modulation signal (PWM modulation signal). The pulse width modulation signal can act on the SiC-MOSFET (silicon carbide semiconductor switch) inside the APF (active power filter) to generate a compensation current.

[0041] Step S104, using a pulse width modulation signal to control a silicon carbide semiconductor switch to generate a target compensation current, wherein the target compensation current is used to control harmonics generated in a power grid, and the silicon carbide semiconductor switch includes: a semiconductor switch made of silicon carbide material.

[0042] In this embodiment, a pulse width modulation signal can be sent to SiC-MOSFET (silicon carbide semiconductor switch), and SiC-MOSFET can switch quickly at an average switching frequency of more than 40kHz (much higher than 20kHz of IGBT switch) according to the received PWM signal (corresponding to the pulse width modulation signal), generating a compensation current (ica, icb, icc) that matches the command reference value of the compensation current. Since SiC-MOSFET has the characteristics of low switching loss and high thermal conductivity, it can maintain high efficiency (98.5% to 99%) and low power consumption even at high switching frequencies.

[0043] Through the above steps, in this embodiment, a pulse width modulation signal is generated by using a composite controller and a pulse width modulator, and then the pulse width modulation signal is used to act on the APF (active power filter) to generate a compensation current to control the harmonics in the power grid, thereby avoiding the difficulty of a single traditional control method in coping with variable frequency amplitude changes, thereby achieving the technical effect of improving the accuracy of harmonic current tracking compensation. In addition, the technical problem that in the process of tracking and compensating harmonics in the related art, only a PI controller is used to generate a PWM signal, and the tracking and compensating control effect of the harmonic current is poor is solved.

[0044] Optionally, based on the instruction reference value, a pulse width modulated signal is generated using a composite controller and a pulse width modulator, including: determining the harmonic current in the load current signal to obtain a harmonic current signal; inputting the harmonic current signal and the instruction reference value into the composite controller, and outputting a pre-compensation current reference value, wherein the pre-compensation current reference value includes: reference data of the compensation current to be generated; inputting the pre-compensation current reference value into the pulse width modulator, and outputting a pulse width modulated signal.

[0045] In this embodiment, the harmonic current signal and the command reference value may be input into the composite controller to output a pre-compensation current reference value, and the pre-compensation current reference value may be input into the PWM modulator to output a pulse width modulation signal.

[0046] Figure 2 is a schematic diagram of an optional composite controller according to an embodiment of the present invention, such as Figure 2 As shown, I ref (z) can represent the reference current (corresponding to the command reference value), I in (z) can represent the current signal output by the controller, G PI2 (z) can represent the PI controller of the current inner loop, z k can represent the phase compensation link, S(z) can represent the compensator, Q(z) can represent the stability coefficient, k r It can be expressed as the repetitive control gain coefficient, z -N It can represent the delay link, G d (z) can represent the PWM modulator transfer function.

[0047] The repetitive controller is mainly composed of the control internal model G in (z), delay link z -N and compensator S(z), the current closed-loop error transfer function G under composite control can be obtained e (z) is expressed as:

[0048]

[0049] Among them, G d (z) is the equivalent transfer function of PWM modulation. According to the input signal characteristics, the control internal model G of the repetitive controller in (z) can be designed by the stability factor Q(z), and the design formula is:

[0050]

[0051] Among them, the selection of Q(z) is closely related to steady-state accuracy and stability, and the system robustness and steady-state error can be comprehensively considered. According to actual engineering conditions, in this embodiment, 0.95 can be selected as the internal model stability coefficient.

[0052] According to the control internal model G of the repetitive controller in From the design formula of (z), it can be seen that as long as the current closed-loop system of the repetitive controller is stable, the composite controller can achieve stable current tracking control. The characteristic equation of the repetitive control current closed-loop system is:

[0053]

[0054] Therefore, it can be obtained that when the controller is running stably, the repeated control gain coefficient k r The formula for obtaining the value is:

[0055]

[0056] Among them, the compensator S(z) can be designed to consider different frequency bands respectively. For the phase shift generated by the inner loop of the mid-frequency band current, the mid-high frequency band and the high frequency band harmonics, the controller G is used respectively. 1 (z), G 2 (z) and second-order low-pass filter G 3 (z) is compensated, and the obtained repetitive control compensation controller S(z) is:

[0057] G 1 (z) = z k

[0058]

[0059] S(z)=G 1 (z)G 2 (z)G 3 (z)

[0060] Among them, zm represents the mth discrete state before the current moment, T s represents the sampling period, ξ represents the system damping ratio, ω c represents the system cutoff frequency, and z-2m represents the discrete state of the 2mth beat before the current moment.

[0061] In this embodiment, generating a pulse width modulation signal may include: (1) current error calculation: first, the repetitive controller may receive the grid current and calculate the harmonic current reference value through a harmonic detection algorithm (such as adaptive noise cancellation theory ANCT). Then, the compensation current actually output by the APF is compared with this reference value to calculate the current error. PI control: The current error signal is sent to the PI controller, and the PI controller outputs a control signal based on the size and rate of change of the error. This control signal can respond quickly to error changes and provide an appropriate compensation to reduce the error. (2) Repetitive control: Considering the periodic harmonics in the power grid, the repetitive controller can also integrate a repetitive control mechanism. The repetitive controller can learn through an internal model based on the control signal and error signal of the previous cycle to reduce future periodic errors. The output signal of the repetitive controller is combined with the output signal of the PI control to form a pre-compensation current reference value, which is the basis for obtaining the modulation signal. (3) Modulation signal synthesis: The output signal of the composite controller (the composite signal of PI control and repetitive control) is further processed, such as filtering and limiting, to ensure the stability and adaptability of the signal, and the modulation signal is obtained by using the PWM modulator. This signal will be used to modulate the inverter output of the APF. (3) PWM modulation: The final modulation signal is converted into a PWM signal. Based on this signal, the PWM modulator converts the DC voltage into a series of pulse voltages. The width and position of these pulse voltages vary with the modulation signal, thereby controlling the switching time of the SIC-MOSFET in the APF inverter bridge, so that the compensation current output by the inverter can track the reference harmonic current and achieve harmonic suppression.

[0062] Optionally, after using a pulse width modulation signal to control the silicon carbide semiconductor switch to generate a target compensation current, it also includes: using an inductor to inject the target compensation current into a power grid; after injecting the target compensation current into the power grid, detecting the current of the power grid to obtain a detection result, wherein the detection result includes: a component of a harmonic current in the power grid.

[0063] In this embodiment, the compensation current is injected into the power grid through the inductor (La, Lb, Lc), which can offset the bad current components generated by the load to ensure that the power grid current presents a sinusoidal waveform. At the same time, the APF can monitor the harmonic current components in the power grid in real time, detect whether the harmonic current components in the power grid exceed expectations, evaluate the compensation effect, and adjust the compensation strategy when the harmonic current components in the power grid exceed expectations, thereby achieving the technical effect of accurately suppressing the harmonics generated by the nonlinear load in the power grid.

[0064] Optionally, after using a pulse width modulation signal to control the silicon carbide semiconductor switch to generate a target compensation current, it also includes: comparing the target compensation current and the instruction reference value to obtain a comparison result; based on the second comparison result, determining whether to adjust the compensation strategy, wherein the compensation strategy includes: a control strategy for controlling harmonics generated by the power grid.

[0065] In this embodiment, the current compensation process is a closed-loop control process. The current tracking controller can be adjusted according to the difference (error signal) between the actual output compensation current (corresponding to the target compensation current) and the command reference value to improve the compensation accuracy. A composite controller (for example, a PI controller combined with a repetitive controller) can be used to maintain high-precision compensation within a wide frequency band (2nd to 50th harmonics) while ensuring fast dynamic response (the response time is stabilized within 10ms).

[0066] It should be noted that the harmonic compensation effect can also be verified. For example, the effect of current tracking compensation is evaluated by measuring the total harmonic distortion (THDI) of the grid current to ensure that the THDI after treatment is less than 5% and the current imbalance is less than 5%, meeting the high standards for power quality.

[0067] Optionally, the load current signal is input into a digital signal processor in a parallel active power filter to obtain a command reference value, including: inputting the load current signal into a digital signal processor in the parallel active power filter, and using the digital signal processor to analyze the load current signal to obtain an analysis result, wherein the analysis result at least includes: a harmonic component in the load current signal; and generating a command reference value based on the analysis result.

[0068] In this embodiment, after receiving the load current signal, the DSP (digital signal processor) can analyze and extract the harmonics, reactive power and unbalanced components in the load current through Fourier transform or instantaneous reactive power theory (such as PQ, IP-IQ method) and other algorithms. Based on these analysis results, the DSP can calculate the command reference value (ICR) of the compensation current, including the magnitude and phase information, to ensure that the compensation current injected into the power grid can be equal to the undesirable component of the load and opposite in phase.

[0069] Optionally, based on the pulse width modulation signal, the silicon carbide semiconductor switch is controlled to switch at a preset switching frequency to obtain a target compensation current, wherein the preset switching frequency is used to control the switching frequency of the silicon carbide semiconductor switch.

[0070] For example, a PWM signal can be sent to the driver circuit of the SiC-MOSFET switch. The driver circuit provides the required gate voltage for the SiC-MOSFET, ensuring that the SiC-MOSFET switch can be accurately turned on and off at a preset switching frequency in a very short time (e.g., within 200ns). The driver circuit design can take into account the high dv / dt (voltage change rate between gate and source) characteristics of the SiC-MOSFET, and use a driver chip with high CMTI (Common-Mode Transient Immunity) capability to reduce interference with the circuit during the switching process. By controlling the dead time of the SiC-MOSFET (the time that the current flows through the body diode during the off state), the loss can be further reduced and the efficiency can be improved. In SiC-MOSFET, the dead time can be set shorter to reduce the use of the body diode and avoid device performance degradation.

[0071] Control of inverter output current: By controlling the switching sequence and time interval of SiC-MOSFET, the inverter can output a compensation current that matches the command reference current. The compensation current output by the inverter offsets the harmonic components in the load current, thereby improving the power quality of the power grid.

[0072] In an optional example, generating a pulse width modulation signal may also include: generating a control signal based on a command reference value and a current output by an inverter in a power grid; and converting the control signal using a pulse width modulator to obtain a pulse width modulation signal.

[0073] For example, the command reference current (or command reference value) can be fed into the current tracking controller. The current tracking controller can generate a control signal based on the deviation between the command reference current and the actual inverter output current. The control signal is converted into a switching signal, namely a PWM signal, through a modulator (e.g., a PWM modulator). The PWM signal can determine the switching moment of the internal SiC-MOSFET, thereby controlling the inverter to generate a compensation current that matches the command reference current. Specifically, the duty cycle of the PWM signal is adjusted to ensure that the compensation current output by the inverter is consistent with the magnitude and phase of the command reference current, thereby offsetting the harmonic components on the load side.

[0074] Optionally, a current transformer is deployed between the power grid and the load side of the power grid, and the current on the load side of the power grid is detected by the current transformer to obtain a load current signal, including: using the primary side of the current transformer and the secondary side of the current transformer to collect the current on the load side to obtain an analog current signal; converting the analog current signal into a digital signal to obtain a load current signal.

[0075] For example, a suitable current transformer (CT) can be selected according to the range and characteristics of the load current. The current transformer should have good linearity and wide-band response to ensure that the harmonic components in the load-side current can be accurately reflected. The current transformer can be installed in the load-side current path, usually at the connection point between the power grid and the load. The primary winding of the transformer is connected in series in the load current path, and the secondary winding is connected to the detection circuit.

[0076] When the load current flows through the primary winding of the current transformer, a secondary current proportional to the load current is generated. The secondary current signal is sent to the signal conditioning circuit, such as the amplifier circuit, to ensure that the signal strength is suitable for subsequent digital signal processing. At the same time, the signal conditioning circuit can also filter out noise and improve signal quality. After that, the analog current signal on the secondary side is converted into a digital signal through an analog-to-digital converter (ADC) to obtain a load current signal, which is convenient for the DSP (digital signal processor) to perform calculations and processing.

[0077] In this embodiment, the high power density detuning device using the new SiC-MOSFET technology can achieve accurate and efficient management of power quality issues, improve the power quality of the power grid, and has the advantages of small size, light weight and high efficiency.

[0078] In this embodiment, the command reference value and the detected harmonic current are input into a composite current tracking compensation controller (corresponding to a composite controller), and a PWM modulation signal is output. The modulation signal acts on the SiC-MOSFET inside the APF to generate a compensation current, which can cope with variable frequency amplitude changes, and has high real-time, flexibility and adaptability of control, and can simultaneously meet the stable, accurate and fast dynamic harmonic compensation requirements in complex scenarios.

[0079] Embodiment 2

[0080] The second embodiment of the present invention provides an optional composite current tracking compensation device, and each implementation unit in the composite current tracking compensation device corresponds to each implementation step in the first embodiment.

[0081] Figure 3 is a schematic diagram of an optional composite current tracking compensation device according to an embodiment of the present invention, such as Figure 3 As shown, the composite current tracking compensation device includes: a detection unit 31, a processing unit 32, a first generation unit 33 and a second generation unit 34.

[0082] The detection unit 31 is used to detect the current on the load side of the power grid through a current transformer to obtain a load current signal;

[0083] The processing unit 32 is used to input the load current signal into the digital signal processor in the parallel active power filter to obtain the instruction reference value, wherein the instruction reference value includes: the magnitude and phase information of the compensation current to be generated;

[0084] A first generating unit 33 is used to generate a pulse width modulation signal based on the instruction reference value by using a composite controller and a pulse width modulator, wherein the composite controller is composed of a proportional integral controller and a repetitive controller;

[0085] The second generating unit 34 is used to control the silicon carbide semiconductor switch to generate a target compensation current using a pulse width modulation signal, wherein the target compensation current is used to control harmonics generated in the power grid, and the silicon carbide semiconductor switch includes: a semiconductor switch made of silicon carbide material.

[0086] In the composite current tracking compensation device provided in the second embodiment of the present invention, the detection unit 31 can detect the current on the load side of the power grid through the current transformer to obtain the load current signal, and the load current signal can be input into the digital signal processor in the parallel active power filter through the processing unit 32 to obtain the instruction reference value, wherein the instruction reference value includes: the magnitude and phase information of the compensation current to be generated, and the first generation unit 33 generates a pulse width modulation signal based on the instruction reference value by using the composite controller and the pulse width modulator, wherein the composite controller is composed of a proportional integral controller and a repetitive controller, and the second generation unit 34 uses the pulse width modulation signal to control the silicon carbide semiconductor switch to generate the target compensation current, wherein the target compensation current is used to control the harmonics generated in the power grid, and the silicon carbide semiconductor switch includes: a semiconductor switch made of silicon carbide material. Thus, the technical problem that in the process of tracking and compensating the harmonics in the related art, only the PI controller is used to generate the PWM signal, and the tracking and compensating control effect of the harmonic current is poor is solved.

[0087] In this embodiment, a composite controller and a pulse width modulator are used to obtain a pulse width modulated signal, which is then used to generate a compensation current to control the harmonics in the power grid, thereby avoiding the situation where a single traditional control method is difficult to cope with variable frequency amplitude changes, thereby achieving the technical effect of improving the accuracy of harmonic current tracking compensation.

[0088] Optionally, in the composite current tracking compensation device provided in Embodiment 2 of the present invention, the first generating unit includes: a determining subunit, used to determine the harmonic current in the load current signal to obtain a harmonic current signal; a first processing subunit, used to input the harmonic current signal and the instruction reference value into the composite controller, and output a pre-compensation current reference value, wherein the pre-compensation current reference value includes: reference data of the compensation current to be generated; and a second processing subunit, used to input the pre-compensation current reference value into a pulse width modulator, and output a pulse width modulated signal.

[0089] Optionally, in the composite current tracking compensation device provided in Embodiment 2 of the present invention, the composite current tracking compensation device includes: an injection unit, which is used to inject the target compensation current into the power grid using an inductor after controlling the silicon carbide semiconductor switch to generate the target compensation current using a pulse width modulation signal; a detection unit, which is used to detect the current of the power grid after the target compensation current is injected into the power grid, and obtain a detection result, wherein the detection result includes: the component of the harmonic current in the power grid.

[0090] Optionally, in the composite current tracking compensation device provided in Embodiment 2 of the present invention, the composite current tracking compensation device also includes: a comparison unit, for comparing the target compensation current and the instruction reference value to obtain a second comparison result after controlling the silicon carbide semiconductor switch to generate the target compensation current using a pulse width modulation signal; and a determination unit, for determining whether to adjust the compensation strategy based on the comparison result, wherein the compensation strategy includes: a control strategy for controlling harmonics generated by the power grid.

[0091] Optionally, in the composite current tracking compensation device provided in Embodiment 2 of the present invention, the processing unit includes: a third processing sub-unit, used to input the load current signal into a digital signal processor in a parallel active power filter, and use the digital signal processor to analyze the load current signal to obtain an analysis result, wherein the analysis result at least includes: a harmonic component in the load current signal; and a generation sub-unit, used to generate an instruction reference value based on the analysis result.

[0092] Optionally, in the composite current tracking compensation device provided in Embodiment 2 of the present invention, the second generating unit includes: based on a pulse width modulation signal, controlling the silicon carbide semiconductor switch to switch according to a preset switching frequency to obtain a target compensation current, wherein the preset switching frequency is used to control the switching frequency of the silicon carbide semiconductor switch.

[0093] Optionally, in the composite current tracking compensation device provided in Embodiment 2 of the present invention, the current transformer is deployed between the power grid and the load side of the power grid, and the detection unit includes: a collection subunit, which is used to collect the current on the load side using the primary side of the current transformer and the secondary side of the current transformer to obtain an analog current signal; and a conversion subunit, which is used to convert the analog current signal into a digital signal to obtain a load current signal.

[0094] The above-mentioned composite current tracking compensation device may also include a processor and a memory. The above-mentioned detection unit 31, processing unit 32, first generation unit 33 and second generation unit 34 are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions.

[0095] The processor includes a kernel, which retrieves the corresponding program unit from the memory. One or more kernels can be set, and the composite controller and the pulse width modulator are used to adjust the kernel parameters to obtain the pulse width modulation signal, and then the pulse width modulation signal is used to generate the compensation current to control the harmonics in the power grid, thereby avoiding the difficulty of a single traditional control method in coping with the variable frequency amplitude changes, thereby achieving the technical effect of improving the accuracy of harmonic current tracking compensation.

[0096] The above-mentioned memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one storage chip.

[0097] According to another aspect of an embodiment of the present invention, there is also provided an electronic device, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to perform a composite current tracking compensation method by executing the executable instructions.

[0098] According to another aspect of an embodiment of the present invention, a non-volatile storage medium is provided, wherein the non-volatile storage medium stores a program, wherein when the program is executed, the device where the non-volatile storage medium is located is controlled to execute a composite current tracking compensation method.

[0099] Figure 4 is a schematic diagram of an electronic device according to an embodiment of the present invention, such as Figure 4 As shown, an embodiment of the present invention provides an electronic device 40, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, any one of the above composite current tracking compensation methods is implemented.

[0100] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0101] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0102] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0103] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0104] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0105] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0106] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A composite current tracking compensation method, characterized in that: include: The current on the load side of the power grid is detected by a current transformer to obtain a load current signal; Inputting the load current signal into a digital signal processor in a parallel active power filter to obtain a command reference value, wherein the command reference value includes: the magnitude and phase information of the compensation current to be generated; Based on the command reference value, a pulse width modulation signal is generated by using a compound controller and a pulse width modulator, wherein the compound controller is composed of a proportional integral controller and a repetitive controller; The pulse width modulation signal is used to control the silicon carbide semiconductor switch to generate a target compensation current, wherein the target compensation current is used to control harmonics generated in the power grid, and the silicon carbide semiconductor switch includes: a semiconductor switch made of silicon carbide material.

2. The composite current tracking compensation method according to claim 1, characterized in that: Based on the command reference value, a pulse width modulation signal is generated by using a composite controller and a pulse width modulator, including: Determining the harmonic current in the load current signal to obtain a harmonic current signal; The harmonic current signal and the command reference value are input into the composite controller, and a pre-compensation current reference value is output, wherein the pre-compensation current reference value includes: reference data of the compensation current to be generated; The pre-compensation current reference value is input into the pulse width modulator, and the pulse width modulation signal is output.

3. The composite current tracking compensation method according to claim 1, characterized in that: After using the pulse width modulation signal to control the silicon carbide semiconductor switch to generate the target compensation current, the method further includes: Injecting the target compensation current into the power grid by using an inductor; After the target compensation current is injected into the power grid, the current of the power grid is detected to obtain a detection result, wherein the detection result includes: a component of harmonic current in the power grid.

4. The composite current tracking compensation method according to claim 1, characterized in that: After using the pulse width modulation signal to control the silicon carbide semiconductor switch to generate the target compensation current, the method further includes: comparing the target compensation current and the command reference value to obtain a second comparison result; Based on the comparison result, it is determined whether to adjust a compensation strategy, wherein the compensation strategy includes: a control strategy for controlling harmonics generated by the power grid.

5. The composite current tracking compensation method according to claim 1, characterized in that: Inputting the load current signal into a digital signal processor in a parallel active power filter to obtain a command reference value includes: Inputting the load current signal into a digital signal processor in a parallel active power filter, and using the digital signal processor to analyze the load current signal to obtain an analysis result, wherein the analysis result at least includes: a harmonic component in the load current signal; Based on the analysis result, the instruction reference value is generated.

6. The composite current tracking compensation method according to claim 1, characterized in that: Using the pulse width modulation signal to control the silicon carbide semiconductor switch to generate a target compensation current includes: Based on the pulse width modulation signal, the silicon carbide semiconductor switch is controlled to switch according to a preset switching frequency to obtain the target compensation current, wherein the preset switching frequency is used to control the switching frequency of the silicon carbide semiconductor switch.

7. The composite current tracking compensation method according to claim 1, characterized in that: The current transformer is deployed between the power grid and the load side of the power grid, and the current on the load side of the power grid is detected by the current transformer to obtain a load current signal, including: The current on the load side is collected by using the primary side of the current transformer and the secondary side of the current transformer to obtain an analog current signal; The analog current signal is converted into a digital signal to obtain the load current signal.

8. A composite current tracking compensation device, characterized in that: include: A detection unit, used to detect the current on the load side of the power grid through a current transformer to obtain a load current signal; A processing unit, used for inputting the load current signal into a digital signal processor in a parallel active power filter to obtain a command reference value, wherein the command reference value includes: the magnitude and phase information of the compensation current to be generated; a first generating unit, configured to generate a pulse width modulation signal based on the command reference value by using a compound controller, wherein the compound controller is composed of a proportional integral controller and a repetitive controller; The second generating unit is used to control the silicon carbide semiconductor switch to generate a target compensation current using the pulse width modulation signal, wherein the target compensation current is used to control the harmonics generated in the power grid, and the silicon carbide semiconductor switch includes: a semiconductor switch made of silicon carbide material.

9. A non-volatile storage medium, characterized in that: The non-volatile storage medium stores a program, wherein when the program is running, the device where the non-volatile storage medium is located is controlled to execute the composite current tracking compensation method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: It includes one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the composite current tracking compensation method described in any one of claims 1 to 7.

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