Circuit control method and apparatus

Abstract

The application provides a circuit control method and device, and relates to the technical field of energy storage. The method comprises the following steps: when it is detected that there is a double-frequency ripple on the input side of a single-phase grid-connected inverter, obtaining a DC bus voltage on the input side of the single-phase grid-connected inverter; performing bus voltage outer loop control on the difference between an instruction value corresponding to the DC bus voltage and the DC bus voltage, to obtain a bus voltage outer loop output value; obtaining a current instruction value according to the bus voltage outer loop output value and an output current of a DC / DC conversion circuit; performing current closed-loop control on the difference between the current instruction value and an inductor current of the DC / DC conversion circuit, to obtain a modulation wave; generating a driving signal of a switching tube in the DC / DC conversion circuit according to the modulation wave and a carrier wave, so as to control the on-off of the switching tube through the driving signal, adjust the output power of the DC / DC conversion circuit, and suppress the double-frequency ripple on the input side of the single-phase grid-connected inverter.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a circuit control method and device. Background Technology

[0002] With societal development, the demand for energy is constantly increasing, and the application of energy storage systems is becoming more and more widespread. An energy storage system typically consists of a storage battery, a DC / DC (Direct Current / Direct Current) converter circuit, and a single-phase grid-connected inverter. The storage battery is connected to the input of the DC / DC converter circuit, and the output of the DC / DC converter circuit is connected to the input of the single-phase grid-connected inverter. The output of the single-phase grid-connected inverter is connected to the AC power grid to input AC power. The instantaneous AC power at the output of the single-phase grid-connected inverter is not equal to the DC power at the input, resulting in a second harmonic ripple at the input. This second harmonic ripple adversely affects the inverter's performance.

[0003] In related technologies, a DC filter circuit is connected in parallel at the output of a single-phase grid-connected inverter to transfer the second harmonic ripple generated by power conversion to the DC filter circuit for filtering. However, this solution requires the introduction of additional hardware, which is costly. Summary of the Invention

[0004] This application provides a circuit control method that can suppress second-harmonic ripple without introducing additional filtering circuitry. The technical solution is as follows:

[0005] In a first aspect, a circuit control method is provided, the method comprising:

[0006] When a second-harmonic ripple is detected on the input side of the single-phase grid-connected inverter, the DC bus voltage on the input side of the single-phase grid-connected inverter is obtained.

[0007] The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is used to perform outer loop control of the bus voltage to obtain the outer loop output value of the bus voltage.

[0008] The current command value is obtained based on the outer loop output value of the bus voltage and the output current of the DC / DC / DC converter circuit. The input and output terminals of the DC / DC converter circuit are respectively connected to the energy storage battery and the input terminal of the single-phase grid-connected inverter.

[0009] The difference between the current command value and the inductor current of the DC / DC converter circuit is used for current closed-loop control to obtain a modulated wave.

[0010] Based on the modulation wave and carrier wave, a drive signal is generated for the switching transistor in the DC / DC converter circuit, so as to control the switching transistor to turn on and off through the drive signal, so that the output power of the DC / DC converter circuit suppresses the double-frequency ripple power on the input side of the single-phase grid-connected inverter.

[0011] In one possible implementation, the step of performing outer-loop control of the bus voltage using the command value corresponding to the DC bus voltage and the difference between the DC bus voltage and the command value includes:

[0012] The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is used for proportional resonance (PR) control.

[0013] In one possible implementation, the step of performing outer-loop control of the bus voltage using the command value corresponding to the DC bus voltage and the difference between the DC bus voltage and the command value includes:

[0014] The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is subjected to proportional-integral (PI) control.

[0015] In one possible implementation, the step of performing proportional-integral (PI) control on the command value corresponding to the DC bus voltage and the difference between the DC bus voltage includes:

[0016] The DC bus voltage is subjected to band-stop filtering;

[0017] The difference between the command value corresponding to the DC bus voltage and the voltage output of the band-stop filter is used for PI control.

[0018] In one possible implementation, before obtaining the current command value based on the outer loop output value of the bus voltage and the output current of the DC / DC / DC converter circuit, the method further includes:

[0019] The output current of the DC / DC converter circuit is obtained based on the transfer function of the DC bus current on the input side of the single-phase grid-connected inverter and the voltage of the energy storage battery.

[0020] In one possible implementation, performing current closed-loop control on the low-pass filtered output signal includes:

[0021] The signal output from the low-pass filter is then subjected to PR control.

[0022] In one possible implementation, performing current closed-loop control on the low-pass filtered output signal includes:

[0023] The signal output from the low-pass filter is then subjected to PI control.

[0024] Secondly, a circuit-controlled device is provided, the device comprising:

[0025] The acquisition module is used to acquire the DC bus voltage on the input side of the single-phase grid-connected inverter when a second harmonic ripple is detected on the input side of the single-phase grid-connected inverter.

[0026] The control module is used to perform outer-loop control of the bus voltage by taking the command value corresponding to the DC bus voltage and the difference between the DC bus voltage, to obtain the outer-loop output value of the bus voltage; to obtain a current command value based on the outer-loop output value of the bus voltage and the output current of the DC / DC / DC converter circuit, wherein the input and output terminals of the DC / DC converter circuit are respectively connected to the energy storage battery and the input terminal of the single-phase grid-connected inverter; to perform closed-loop control of the current command value and the difference between the inductor current of the DC / DC converter circuit, to obtain a modulation wave; and to generate a drive signal for the switching transistor in the DC / DC converter circuit based on the modulation wave and the carrier wave, so as to control the switching transistor to turn on and off through the drive signal, so that the output power of the DC / DC converter circuit suppresses the second harmonic ripple power on the input side of the single-phase grid-connected inverter.

[0027] In one possible implementation, the control module is configured to:

[0028] The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is used for proportional resonance (PR) control.

[0029] In one possible implementation, the control module is configured to:

[0030] The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is subjected to proportional-integral (PI) control.

[0031] In one possible implementation, the control module is configured to:

[0032] The DC bus voltage is subjected to band-stop filtering;

[0033] The difference between the command value corresponding to the DC bus voltage and the voltage output of the band-stop filter is used for PI control.

[0034] In one possible implementation, the control module is configured to:

[0035] The output current of the DC / DC converter circuit is obtained based on the transfer function of the DC bus current on the input side of the single-phase grid-connected inverter and the voltage of the energy storage battery.

[0036] In one possible implementation, the control module is configured to:

[0037] The signal output from the low-pass filter is then subjected to PR control.

[0038] In one possible implementation, the control module is configured to:

[0039] The signal output from the low-pass filter is then subjected to PI control.

[0040] Thirdly, a computing device is provided, the computing device including a processor and a memory, the memory storing at least one instruction, the instruction being loaded and executed by the processor to perform the operations performed as described in the first aspect and any possible implementation of the circuit control method described in the first aspect.

[0041] Fourthly, a computer-readable storage medium is provided, the storage medium storing at least one instruction that is loaded and executed by a processor to perform the operations performed by the first aspect and any possible method of circuit control described in the first aspect.

[0042] Fifthly, a computer program product is provided, the computer program product storing at least one instruction, the instruction being loaded and executed by a processor to perform the operations performed as described in the first aspect and any possible implementation of the circuit control method described in the first aspect.

[0043] The beneficial effects of the technical solution provided in this application are:

[0044] In the technical solution provided in this application, when a second harmonic ripple is detected on the input side of a single-phase grid-connected inverter, the DC bus voltage on the input side of the single-phase grid-connected inverter is obtained. At this time, the DC bus voltage contains a second harmonic ripple. Then, the DC bus voltage is subjected to voltage outer loop control and current closed loop control to generate a drive signal to control the on / off state of the switching transistor in the DC / DC conversion circuit, so as to adjust the output power of the DC / DC conversion circuit and buffer the second harmonic ripple power on the input side of the single-phase grid-connected inverter, thereby achieving the purpose of suppressing the second harmonic ripple. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of this application;

[0047] Figure 2 This is a schematic diagram of the structure of an energy storage system provided in an embodiment of this application;

[0048] Figure 3 This is a schematic flowchart of a circuit control method provided in an embodiment of this application;

[0049] Figure 4 This is a schematic flowchart of a circuit control method provided in an embodiment of this application;

[0050] Figure 5 This is a schematic flowchart of a circuit control method provided in an embodiment of this application;

[0051] Figure 6 This is a schematic flowchart of a circuit control method provided in an embodiment of this application;

[0052] Figure 7 This is a schematic diagram of the structure of a circuit-controlled device provided in an embodiment of this application;

[0053] Figure 8 This is a schematic diagram of the structure of a computing device provided in an embodiment of this application. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0055] To facilitate understanding, the terminology used in this application will be explained below:

[0056] Second harmonic ripple

[0057] The instantaneous AC power at the output of a single-phase grid-connected inverter is not equal to the DC power at the input, resulting in a second harmonic ripple at the input. A second harmonic ripple is a voltage or current fluctuation with a frequency twice the grid frequency.

[0058] PI (Proportional-Integral) Control

[0059] PI control is a commonly used closed-loop control strategy for adjusting system errors. The PI controller combines proportional and integral control methods. The basic control principle of PI control is as follows:

[0060] Proportional control: This method directly converts the error into a control output through a proportional gain (Kp). Proportional control makes the controller's output proportional to the error; the larger the error, the larger the controller's output, meaning the controller will more actively adjust the system. However, pure proportional control has a steady-state error, meaning the error is not zero when the system reaches steady state.

[0061] Integral control: This method integrates the error using the integral gain (Ki) and accumulates the integral result as part of the control output. Integral control can eliminate steady-state errors, allowing the system to reach the desired output in steady state. However, integral control can lead to a slower system response, and even overshoot and oscillations.

[0062] PI controller output: The proportional control term and the integral control term are added together to form the output of the PI controller. This output is used to regulate the system to achieve the desired performance.

[0063] PR (Proportional Resonant) Control

[0064] PR control is primarily used to increase the gain at specific frequency points to improve the system's voltage regulation accuracy and suppress harmonics at specific frequencies. For example, in a rectifier converter circuit, the rectified DC bus voltage may exhibit a 100Hz pulsating voltage; a PR controller can effectively suppress this pulsation. The controller's transfer function typically consists of a proportional term and a resonant term. The proportional term ensures the tracking accuracy of the DC component, while the resonant term improves the tracking performance of the AC component.

[0065] This application provides a circuit control method, which can be implemented using a computing device or a separate processor. This method can be used in energy storage systems. See also... Figure 1 The diagram shows a schematic of an energy storage system.

[0066] like Figure 1 As shown, the energy storage system includes an energy storage battery power supply system and a single-phase grid-connected inverter. The energy storage battery power supply system includes an energy storage battery and a DC / DC conversion circuit.

[0067] The input of the DC / DC converter is connected to the energy storage battery, and the output is connected to the input of a single-phase grid-connected inverter, whose output can be connected to the power grid. The energy storage battery stores electrical energy and outputs DC power to the DC / DC converter. The DC / DC converter converts the input DC power and outputs it to the single-phase grid-connected inverter. The single-phase grid-connected inverter converts the input DC power into AC power and outputs it to the power grid.

[0068] In one possible implementation, such as Figure 2 As shown, the energy storage system may also include at least one photovoltaic power supply system. The photovoltaic power supply system includes a photovoltaic panel and a photovoltaic optimizer. The output end of the photovoltaic panel is connected to the input end of the photovoltaic optimizer, and the output end of the photovoltaic optimizer is connected to the input end of the single-phase grid-connected inverter. The photovoltaic power supply system is used to output DC power to the single-phase grid-connected inverter.

[0069] In addition, it should be noted that the above Figure 1 and Figure 2 The circuit topologies of the DC / DC converter, photovoltaic optimizer, and single-phase grid-connected inverter shown are all examples, and the specific circuit topologies of the embodiments in this application are not limited.

[0070] In the aforementioned energy storage system, when the instantaneous AC power at the output of a single-phase grid-connected inverter is not equal to the DC power at the input, it may cause a second harmonic ripple to be generated at the input of the single-phase grid-connected inverter.

[0071] The power relationship of the energy storage system can be represented by the following formula (1):

[0072]

[0073] Among them, P bat P is the output power of the energy storage battery power supply system. PV P represents the output power of the photovoltaic power supply system. dc P represents the DC output power of a single-phase grid-connected inverter. ac This refers to the AC output power of a single-phase grid-connected inverter.

[0074] As can be seen from the above formula (1), the output power P of the battery power supply system can be changed. bat This is used to adjust the power imbalance of the energy storage system and suppress the double frequency ripple at the input terminal (DC bus side) of the single-phase grid-connected inverter.

[0075] The circuit control method provided in this application, when detecting a second harmonic ripple on the input side of a single-phase grid-connected inverter, acquires the DC bus voltage on the input side of the single-phase grid-connected inverter. At this time, the DC bus voltage contains a second harmonic ripple. Then, the DC bus voltage is subjected to voltage outer loop control and current closed loop control to generate a drive signal, which controls the switching transistors in the DC / DC conversion circuit to adjust the output power of the DC / DC conversion circuit, thereby buffering the second harmonic ripple power on the input side of the single-phase grid-connected inverter and achieving the purpose of suppressing the second harmonic ripple.

[0076] The circuit control method provided in the embodiments of this application will be described below with reference to the accompanying drawings. This method can be implemented by a computing device. Figure 3 As shown, the processing of this method may include the following steps:

[0077] Step 301: When a second-harmonic ripple is detected on the input side of the single-phase grid-connected inverter, obtain the DC bus voltage on the input side of the single-phase grid-connected inverter.

[0078] In implementation, the computing device can detect whether there is a second harmonic ripple on the input side of the single-phase grid-connected inverter. When a second harmonic ripple is detected on the input side of the single-phase grid-connected inverter, the DC bus voltage on the input side of the single-phase grid-connected inverter is detected. For ease of explanation, the DC bus voltage is denoted as V. dc ,like Figure 1 Or as shown in Figure 2.

[0079] Step 302: Use the difference between the command value corresponding to the DC bus voltage and the DC bus voltage to perform outer loop control of the bus voltage, and obtain the outer loop output value of the bus voltage.

[0080] In practice, after obtaining the DC bus voltage on the input side of the single-phase grid-connected inverter, the difference between the command value corresponding to the DC bus voltage and the DC bus voltage on the input side of the single-phase grid-connected inverter is calculated to obtain the outer loop output value of the bus voltage.

[0081] Specifically, such as Figure 4 As shown, the command value V corresponding to the DC bus voltage is... dc ref Subtract the DC bus voltage V on the input side of the single-phase grid-connected inverter dc The outer loop output value of the bus voltage is obtained.

[0082] The command value corresponding to the DC bus voltage can be configured by relevant personnel according to actual needs. For example, the command value corresponding to the DC bus voltage can be configured as 400V.

[0083] In one possible implementation, the aforementioned outer loop control of the bus voltage can be PR control.

[0084] The PR controls the tracking of the AC quantity in the DC bus voltage so that it can be subsequently canceled out.

[0085] In another possible implementation, the aforementioned outer loop control of the bus voltage can be PI control.

[0086] Since PI control cannot accurately track AC components, the DC bus voltage can be first band-stop filtered. Accordingly, the processing in step 302 above can be as follows:

[0087] The difference between the command value corresponding to the DC bus voltage and the DC bus voltage after band-stop filtering is used to perform outer loop control of the bus voltage, thus obtaining the outer loop output value of the bus voltage.

[0088] Step 303: Obtain the current command value based on the outer loop output value of the bus voltage and the output current of the DC / DC converter circuit.

[0089] In implementation, such as Figure 4As shown, the outer loop output value of the bus voltage and the output current of the DC / DC converter circuit can be added together to obtain the current command value i. ref For ease of explanation, the output current of the DC / DC converter circuit is denoted as i. FF ,like Figure 1 Or as shown in Figure 2.

[0090] exist Figure 1 In this case, the output current i of the DC / DC converter circuit FF i is the DC bus current on the input side of the single-phase grid-connected inverter. o .

[0091] exist Figure 2 In this case, the output current i of the DC / DC converter circuit FF It is based on the DC bus current i on the input side of the single-phase grid-connected inverter. o The voltage transfer function of the energy storage battery is determined, specifically as shown in the following formula (2):

[0092]

[0093] Among them, G iFF V is the transfer function of the energy storage battery voltage. dc V is the DC bus voltage. dc The output voltage of the energy storage battery, such as Figure 1 Or as shown in Figure 2.

[0094] In one possible implementation, where the outer loop control of the aforementioned bus voltage can be PI control, since the AC component of the DC bus voltage has been filtered out, it is necessary to superimpose the AC component into the current command value. Accordingly, i can be adjusted accordingly. FF The calculation method is updated to... Figure 2 Taking the energy storage system shown as an example, i FF The calculation method can be shown in the following formula (3):

[0095]

[0096] Among them, such as Figure 1 Or as shown in Figure 2, V g i is the output voltage of a single-phase grid-connected inverter. g The output current of a single-phase grid-connected inverter, where P is the active power on the output side of the single-phase grid-connected inverter.

[0097] Step 304: Perform current closed-loop control on the difference between the current command value and the inductor current of the DC / DC converter circuit to obtain the modulated wave.

[0098] In implementation, with Figure 1Taking the topology shown in Figure 2 as an example, the inductor current of inductor L1 and the inductor current of inductor L2 in the DC / DC converter circuit can be detected. For ease of explanation, the inductor current of inductor L1 is denoted as i. L1 Let the inductance current of inductor L2 be denoted as i L2 See Figure 4 For the inductor current i of inductor L1 L1 Subtract the inductor current i from the current command value L1 The difference is obtained, and current closed-loop control is applied to this difference to obtain the modulated wave output of the current closed-loop control, denoted as d1. The modulated wave d1 is used to generate the switching transistor S in the DC / DC converter circuit. 11 and switching transistor S 12 The driving signal. For the inductor current i of inductor L2. L2 Subtract the inductor current i from the current command value L2 The difference is obtained, and current closed-loop control is applied to this difference to obtain the modulated wave output of the current closed-loop control, denoted as d2. The modulated wave d2 is used to generate the switching transistor S in the DC / DC converter circuit. 21 and switching transistor S 22 The driving signal is a low-frequency converted DC wave.

[0099] If the DC / DC converter circuit topology includes only inductor L1 and only switching transistor S... 11 and switching transistor S 12 In the above process, it is only necessary to subtract the inductor current i from the current command value. L1 The difference is obtained, and the difference is subjected to current closed-loop control to obtain the modulated wave of the current closed-loop control output.

[0100] In one possible implementation, the above current closed-loop control is PI control.

[0101] In another possible implementation, the above current closed-loop control is PR control.

[0102] In one possible implementation, to make circuit control more accurate and avoid noise in the modulation wave, the inductor current can be low-pass filtered before being subtracted from the current command value.

[0103] like Figure 5 As shown, an LPF (Low-pass filter) is introduced for the inductor current i of inductor L1. L1 , the inductor current i L1 A low-pass filter is applied, and the current command value is subtracted from the low-pass filtered inductor current to obtain the difference. This difference is then used for current closed-loop control to obtain the modulated wave of the current closed-loop control output. For the inductor current i of inductor L2... L2, the inductor current i L2 A low-pass filter is performed, and the current command value is subtracted from the inductor current after the low-pass filter to obtain the difference. This difference is then used for current closed-loop control to obtain the modulated wave of the current closed-loop control output.

[0104] In another possible implementation, to make circuit control more accurate and avoid noise in the modulation wave, the difference between the current command value and the inductor current can be low-pass filtered.

[0105] like Figure 6 As shown, for the inductor current i of inductor L1 L1 Subtract the inductor current i from the current command value L1 The difference is obtained, and this difference is low-pass filtered. Then, the current output from the low-pass filter is subjected to current closed-loop control to obtain the modulated wave of the current closed-loop control output. For the inductor current i of inductor L2... L2 Subtract the inductor current i from the current command value L2 The difference is obtained, and a low-pass filter is applied to the difference. Then, the current output from the low-pass filter is subjected to current closed-loop control to obtain the modulated wave of the current closed-loop control output.

[0106] Step 305: Based on the modulation wave and carrier wave, generate drive signals for the switching transistors in the DC / DC converter circuit, so as to control the switching transistors to turn on and off, adjust the output power of the DC / DC converter circuit, and suppress the double frequency ripple on the input side of the single-phase grid-connected inverter.

[0107] In implementation, the carrier wave can be a triangular wave, with... Figure 1 or Figure 2 Taking the DC / DC converter circuit in the example, the switching transistor S 11 and switching transistor S 12 For the same carrier, denoted as carrier 1, the switching transistor S 21 and switching transistor S 22 The corresponding carrier is denoted as carrier 2, where the phase difference between carrier 1 and carrier 2 is 180 degrees.

[0108] under Figure 1 or Figure 2 Taking the DC / DC converter circuit in the example, the processing steps are explained as follows:

[0109] For the aforementioned modulation wave d1, modulation wave d1 and carrier wave 1 are input to the first comparator. When the voltage value of carrier wave 1 is greater than the voltage of modulation wave d1, the first comparator outputs a high level; when the voltage value of carrier wave 1 is less than the voltage of modulation wave d1, the first comparator outputs a low level. The alternating high and low level signals output by the first comparator are used to control the switching transistor S. 11 The driving signal is denoted as driving signal 1.

[0110] Furthermore, for the aforementioned modulation wave d1, both modulation wave d1 and carrier wave 1 are simultaneously input to a second comparator. When the voltage value of carrier wave 1 is less than the voltage of modulation wave d1, the second comparator outputs a high level; when the voltage value of carrier wave 1 is greater than the voltage of modulation wave d1, the second comparator outputs a low level. The alternating high and low level signals output by the second comparator are used to control the switching transistor S. 12 The driving signal is denoted as driving signal 2.

[0111] In this way, the modulated drive signal 1 and drive signal 2 are complementary, making the switching transistor S 11 When turned on, the switching transistor S 12 Turn off, switch S 11 When turned off, the switching transistor S 12 Conduction.

[0112] For the aforementioned modulated wave d2, modulated wave d2 and carrier wave 2 are input to a third comparator. When the voltage value of carrier wave 2 is greater than the voltage of modulated wave d2, the third comparator outputs a high level; when the voltage value of carrier wave 2 is less than the voltage of modulated wave d2, the third comparator outputs a low level. The alternating high and low level signals output by the third comparator are the signal for switching transistor S. 21 The driving signal is denoted as driving signal 3.

[0113] Furthermore, for the aforementioned modulation wave d2, both modulation wave d2 and carrier wave 2 are simultaneously input to a fourth comparator. When the voltage value of carrier wave 2 is less than the voltage of modulation wave d2, the fourth comparator outputs a high level; when the voltage value of carrier wave 2 is greater than the voltage of modulation wave d2, the fourth comparator outputs a low level. The alternating high and low level signals output by the fourth comparator are used to control the switching transistor S. 22 The driving signal is denoted as driving signal 4.

[0114] Thus, the modulated drive signal 3 and drive signal 4 are complementary, making the switching transistor S 21 When turned on, the switching transistor S 22 Turn off, switch S 21 When turned off, the switching transistor S 22 Conduction.

[0115] By controlling the switching transistors in the DC / DC converter circuit using the aforementioned drive signals, the output power of the DC / DC converter circuit is adjusted to buffer the double-frequency ripple power on the input side of the single-phase grid-connected inverter, thereby suppressing the double-frequency ripple on the input side of the single-phase grid-connected inverter.

[0116] In addition, in order to verify the feasibility of the circuit control method provided in the embodiments of this application, the above method was verified by simulation. According to the simulation results, the output power of the energy storage battery power supply system cancels the second harmonic ripple power on the input side of the single-phase grid-connected inverter, so that the second harmonic ripple of the input side (DC bus) voltage of the energy storage battery power supply system is almost zero, that is, the second harmonic ripple is suppressed.

[0117] All of the above-mentioned optional technical solutions can be combined in any way to form optional embodiments of this disclosure, and will not be described in detail here.

[0118] The technical solution provided in this application, when a second harmonic ripple is detected on the input side of a single-phase grid-connected inverter, obtains the DC bus voltage on the input side of the single-phase grid-connected inverter. At this time, the DC bus voltage contains a second harmonic ripple. Then, voltage outer loop control and current closed loop control are performed on the DC bus voltage to generate a drive signal to control the on / off state of the switching transistors in the DC / DC conversion circuit, so as to adjust the output power of the DC / DC conversion circuit, thereby buffering the second harmonic ripple power on the input side of the single-phase grid-connected inverter and achieving the purpose of suppressing the second harmonic ripple.

[0119] Based on the same technical concept, embodiments of this application also provide a circuit-controlled device, which can be a computing device, such as... Figure 7 As shown, the device includes an acquisition module 510 and a control module 520, wherein:

[0120] The acquisition module 510 is used to acquire the DC bus voltage on the input side of the single-phase grid-connected inverter when a second harmonic ripple is detected on the input side of the single-phase grid-connected inverter.

[0121] The control module 520 is used to perform outer-loop control of the bus voltage by taking the command value corresponding to the DC bus voltage and the difference between the DC bus voltage, to obtain the outer-loop output value of the bus voltage; to obtain a current command value based on the outer-loop output value of the bus voltage and the output current of the DC / DC / DC converter circuit, wherein the input and output terminals of the DC / DC converter circuit are respectively connected to the energy storage battery and the input terminal of the single-phase grid-connected inverter; to perform closed-loop control of the current command value and the difference between the inductor current of the DC / DC converter circuit, to obtain a modulation wave; and to generate a drive signal for the switching transistor in the DC / DC converter circuit based on the modulation wave and the carrier wave, so as to control the switching transistor to turn on and off through the drive signal, so that the output power of the DC / DC converter circuit suppresses the double-frequency ripple power on the input side of the single-phase grid-connected inverter.

[0122] In one possible implementation, the control module 520 is configured to:

[0123] The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is used for proportional resonance (PR) control.

[0124] In one possible implementation, the control module 520 is configured to:

[0125] The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is subjected to proportional-integral (PI) control.

[0126] In one possible implementation, the control module 520 is configured to:

[0127] The DC bus voltage is subjected to band-stop filtering;

[0128] The difference between the command value corresponding to the DC bus voltage and the voltage output of the band-stop filter is used for PI control.

[0129] In one possible implementation, the control module 520 is configured to:

[0130] The output current of the DC / DC converter circuit is obtained based on the transfer function of the DC bus current on the input side of the single-phase grid-connected inverter and the voltage of the energy storage battery.

[0131] In one possible implementation, the control module 520 is configured to:

[0132] The signal output from the low-pass filter is then subjected to PR control.

[0133] In one possible implementation, the control module 520 is configured to:

[0134] The signal output from the low-pass filter is then subjected to PI control.

[0135] In the technical solution provided in this application embodiment, when a second harmonic ripple is detected on the input side of the single-phase grid-connected inverter, the DC bus voltage on the input side of the single-phase grid-connected inverter is obtained. At this time, the DC bus voltage contains a second harmonic ripple. Then, the DC bus voltage is subjected to voltage outer loop control and current closed loop control to generate a drive signal, which controls the switching transistors in the DC / DC conversion circuit to adjust the output power of the DC / DC conversion circuit, thereby buffering the second harmonic ripple power on the input side of the single-phase grid-connected inverter and achieving the purpose of suppressing the second harmonic ripple.

[0136] It should be noted that the circuit control device provided in the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the circuit control can be divided into different functional modules to complete all or part of the functions described above. In addition, the circuit control device and the circuit control method embodiments provided in the above embodiments belong to the same concept, and the specific implementation process can be found in the method embodiments, which will not be repeated here.

[0137] Figure 8 This is a schematic diagram of a computing device provided in an embodiment of this application. The server 1000 can vary considerably due to different configurations or performance. It may include one or more central processing units (CPUs) 1001 and one or more memories 1002. The memory 1002 stores at least one instruction, which is loaded and executed by the processor 1001 to implement the methods provided in the above-described method embodiments. Of course, the computing device may also have wired or wireless network interfaces, a keyboard, and input / output interfaces for input and output. The computing device may also include other components for implementing device functions, which will not be elaborated here.

[0138] In an exemplary embodiment, a computer-readable storage medium is also provided, such as a memory including instructions that can be executed by a processor in a terminal to complete the method for training a neural network model in the above embodiments. This computer-readable storage medium can be non-transitory. For example, the computer-readable storage medium can be ROM (Read-Only Memory), RAM (Random Access Memory), CD-ROM (CompactDisc Read-Only Memory), magnetic tape, floppy disk, and optical data storage devices, etc.

[0139] It should be noted that all information (including but not limited to user equipment information, user personal information, etc.), data (including but not limited to data used for analysis, stored data, displayed data, etc.), and signals (including but not limited to signals transmitted between the user terminal and other devices) involved in this application have been authorized by the user or fully authorized by all parties, and the collection, use, and processing of related data must comply with the relevant laws, regulations, and standards of the relevant countries and regions. For example, the current, voltage, etc. involved in this application were obtained under full authorization.

[0140] In this application, the terms "first," "second," etc., are used to distinguish identical or similar items that have substantially the same function and purpose. It should be understood that there is no logical or temporal dependency between "first" and "second," nor does it limit the quantity or order of execution. It should also be understood that although the following description uses the terms "first," "second," etc., to describe various elements, these elements should not be limited by the terms. These terms are merely used to distinguish one element from another. For example, without departing from the scope of various examples, a first current can be referred to as a second current, and similarly, a second current can be referred to as a first current. Both the first current and the second current can be collectively referred to as current, and in some cases, they can be separate and distinct messages.

[0141] In this application, the term "at least one" means one or more, and the term "multiple" means two or more.

[0142] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0143] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A method for circuit control, characterized in that, The method includes: When a second-harmonic ripple is detected on the input side of a single-phase grid-connected inverter, the DC bus voltage on the input side of the single-phase grid-connected inverter is obtained. The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is used to perform outer loop control of the bus voltage to obtain the outer loop output value of the bus voltage. The current command value is obtained based on the outer loop output value of the bus voltage and the output current of the DC / DC / DC converter circuit. The input and output terminals of the DC / DC converter circuit are respectively connected to the energy storage battery and the input terminal of the single-phase grid-connected inverter. The difference between the current command value and the inductor current of the DC / DC converter circuit is used for current closed-loop control to obtain a modulated wave. Based on the modulation wave and carrier wave, drive signals for the switching transistors in the DC / DC converter circuit are generated to control the switching transistors on and off, thereby adjusting the output power of the DC / DC converter circuit and suppressing the double-frequency ripple on the input side of the single-phase grid-connected inverter.

2. The method according to claim 1, characterized in that, The step of performing outer-loop control of the bus voltage based on the difference between the command value corresponding to the DC bus voltage and the DC bus voltage includes: The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is used for proportional resonance (PR) control.

3. The method according to claim 1, characterized in that, The step of performing outer-loop control of the bus voltage based on the difference between the command value corresponding to the DC bus voltage and the DC bus voltage includes: The difference between the command value corresponding to the DC bus voltage and the DC bus voltage is subjected to proportional-integral (PI) control.

4. The method according to claim 3, characterized in that, The step of performing proportional-integral (PI) control on the difference between the command value corresponding to the DC bus voltage and the DC bus voltage includes: The DC bus voltage is subjected to band-stop filtering; The difference between the command value corresponding to the DC bus voltage and the voltage output of the band-stop filter is used for PI control.

5. The method according to claim 1, characterized in that, Before obtaining the current command value based on the outer loop output value of the bus voltage and the output current of the DC / DC / DC converter circuit, the process further includes: The output current of the DC / DC converter circuit is obtained based on the transfer function of the DC bus current on the input side of the single-phase grid-connected inverter and the voltage of the energy storage battery.

6. The method according to any one of claims 1-5, characterized in that, The step of performing current closed-loop control on the low-pass filtered signal includes: The signal output from the low-pass filter is then subjected to PR control.

7. The method according to any one of claims 1-5, characterized in that, The step of performing current closed-loop control on the low-pass filtered signal includes: The signal output from the low-pass filter is then subjected to PI control.

8. A computing device, characterized in that, The computing device includes a processor and a memory, the memory storing at least one instruction that is loaded and executed by the processor to implement the method as claimed in any one of claims 1 to 7.

9. A computer-readable storage medium, characterized in that, The storage medium stores at least one instruction, which is loaded and executed by a processor to implement the method as described in any one of claims 1 to 7.

10. A computer program product, characterized in that, The computer program product stores at least one instruction, which is loaded and executed by a processor to implement the method as described in any one of claims 1 to 7.

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