Inverter control method, device and system

Abstract

The present disclosure relates to an inverter control method, device and system, which are applied to the field of inverter control technology. The method comprises: obtaining a target voltage corresponding to an inverter, and a first output voltage and a first output current of the current inverter; determining a first target given voltage at a current moment according to the target voltage, a historical given voltage and a preset step voltage, wherein the historical given voltage is the first target given voltage at a previous moment; adjusting the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage; judging whether a difference between the output voltage of the inverter after adjustment and the target voltage is not greater than a first preset voltage difference; if so, controlling the inverter to complete startup; if not, repeating the above steps until a difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference, so as to control the inverter to complete startup.

Description

Technical Field

[0001] The present disclosure relates to the technical field of inverter control, and in particular, to an inverter control method, device and system. Background Art

[0002] With the development of energy storage systems based on distributed power generation technology, energy storage systems can be connected to the grid to facilitate frequency and peak regulation of the power supply system, or they can be operated off-grid (i.e., island mode), with the inverter in the energy storage system supplying power to the load, where the inverter is used to convert DC power (batteries, storage bottles) into AC power. At present, with the growth of energy demand, a single inverter can no longer meet the power supply needs of the load, and multiple inverters need to be connected in parallel to supply power to the load. However, when multiple parallel inverters are started, each inverter will generate a large impact current, which will impact the load and may damage the inverter, affecting the service life of the inverter. Summary of the invention

[0003] In order to solve the problems existing in the related art, the present disclosure provides an inverter control method, device and system.

[0004] In order to achieve the above object, according to a first aspect of an embodiment of the present disclosure, there is provided an inverter control method, the method comprising:

[0005] Step 1: Obtaining a target voltage corresponding to the inverter, and a first output voltage and a first output current of the inverter;

[0006] Step 2: Determine the first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage, wherein the historical given voltage is the first target given voltage at the previous moment;

[0007] Step three: adjusting the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage;

[0008] Step 4: Determine whether the difference between the adjusted output voltage of the inverter and the target voltage is not greater than a first preset voltage difference.

[0009] If yes, the inverter is controlled to start up.

[0010] If not, steps 1 to 4 are repeated until the difference between the adjusted output voltage of the inverter and the target voltage is not greater than the first preset voltage difference, so as to control the inverter to complete startup.

[0011] Optionally, determining the first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage includes:

[0012] When the target voltage is greater than the historical given voltage, and the difference between the target voltage and the historical given voltage is greater than or equal to the step voltage, the sum of the historical given voltage and the step voltage is used as the first target given voltage;

[0013] When the target voltage is greater than the historical given voltage and the difference between the target voltage and the historical given voltage is less than the step voltage, the target voltage is used as the first target given voltage;

[0014] When the target voltage is less than or equal to the historical given voltage, and the difference between the historical given voltage and the target voltage is greater than or equal to the step voltage, the difference between the historical given voltage and the step voltage is used as the first target given voltage;

[0015] When the target voltage is less than or equal to the historical given voltage, and the difference between the historical given voltage and the target voltage is less than the step voltage, the target voltage is used as the first target given voltage.

[0016] Optionally, adjusting the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage includes:

[0017] Determine a first target current according to the first target given voltage and the first output voltage, and determine a first reference voltage according to the first target current and the first output current;

[0018] The output voltage of the inverter is adjusted according to the first reference voltage.

[0019] Optionally, determining a first target current according to the first target given voltage and the first output voltage, and determining a first reference voltage according to the first target current and the first output current includes:

[0020] Performing proportional-integral adjustment on the difference between the first target given voltage and the first output voltage to obtain the first target current;

[0021] Performing proportional-integral adjustment on the difference between the first target current and the first output current to obtain a first voltage;

[0022] performing feed-forward decoupling on the first output current to obtain a second voltage;

[0023] The first reference voltage is determined according to the first voltage and the second voltage.

[0024] Optionally, there are multiple inverters, each of which communicates with each other, and after all the inverters are started, the method further includes:

[0025] Obtaining active power and reactive power output by each of the inverters;

[0026] Determine the average active power according to the active power output by each of the inverters, and determine the average reactive power according to the reactive power output by each of the inverters;

[0027] Obtaining a second output voltage and a second output current of the inverter;

[0028] The output voltage of the inverter is adjusted according to the target voltage, the second output voltage, the second output current, the average active power and the average reactive power so that the output voltage difference between the multiple inverters is not greater than a second preset voltage difference.

[0029] Optionally, adjusting the output voltage of the inverter according to the target voltage, the second output voltage, the second output current, the average active power, and the average reactive power includes:

[0030] Determining a second target given voltage according to the active power, the reactive power, the average active power, the average reactive power and the target voltage output by the inverter;

[0031] Determine a second target current according to the second target given voltage and the second output voltage, and determine a second reference voltage according to the second target current and the second output current;

[0032] The output voltage of the inverter is adjusted according to the second reference voltage.

[0033] Optionally, determining a second target current according to the second target given voltage and the second output voltage, and determining a second reference voltage according to the second target current and the second output current includes:

[0034] Performing proportional-integral adjustment on the difference between the second target given voltage and the second output voltage to obtain the second target current;

[0035] Performing proportional-integral adjustment on the difference between the second target current and the second output current to obtain a third voltage;

[0036] Performing feed-forward decoupling on the second output current to obtain a fourth voltage;

[0037] The second reference voltage is determined according to the third voltage and the fourth voltage.

[0038] Optionally, before acquiring the active power and reactive power output by each inverter, the method further includes:

[0039] Acquire the operating state of each of the inverters, where the operating state includes a normal state or an abnormal state;

[0040] Determining a master inverter among the plurality of inverters according to the operating status;

[0041] The frequency and phase of the output voltage of the slave inverter are synchronized according to the synchronization signal generated by the master inverter, wherein the synchronization signal includes the frequency and phase of the output voltage of the master inverter, and the slave inverter is any inverter except the master inverter.

[0042] According to a second aspect of an embodiment of the present disclosure, an inverter control device is provided, the inverter control device comprising:

[0043] Memory;

[0044] A processor, wherein the processor is used to execute the steps of the inverter control method provided in the first aspect.

[0045] According to a third aspect of an embodiment of the present disclosure, there is provided an inverter control system, including:

[0046] A plurality of inverter modules, wherein the plurality of inverter modules are interconnected and communicate with each other, and each of the inverter modules comprises an inverter;

[0047] The inverter control device shown in the second aspect, wherein the inverter control device is connected to a plurality of the inverter modules;

[0048] A load, wherein the plurality of inverter modules are connected to the loads respectively.

[0049] Through the above technical solution, the present invention obtains the target voltage corresponding to the inverter, and the first output voltage and the first output current of the current inverter, and determines the first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage, wherein the historical given voltage is the first target given voltage at the previous moment, and then adjusts the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage, and judges whether the difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference. If so, the inverter is controlled to complete the startup, and if not, the above steps are repeated until the difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference, so as to control the inverter to complete the startup. The present invention adjusts the first target given voltage multiple times through the step voltage, and adjusts the output voltage of the inverter through the first target given voltage after each adjustment, so that the output voltage of the inverter can smoothly transition to the target voltage, reduce the impact current generated by the inverter startup, and cause less impact on the load, so as to avoid damage to the inverter and extend the service life of the inverter.

[0050] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0052] Figure 1 is a flow chart of an inverter control method according to an exemplary embodiment;

[0053] Figure 2 is a schematic diagram of a control flow of inverter startup according to an exemplary embodiment;

[0054] Figure 3 is a flow chart of another inverter control method according to an exemplary embodiment;

[0055] Figure 4 is a schematic diagram of a control flow after an inverter is started according to an exemplary embodiment;

[0056] Figure 5 is a flow chart of another inverter control method according to an exemplary embodiment;

[0057] Figure 6 is a block diagram of an inverter control device according to an exemplary embodiment;

[0058] Figure 7is a block diagram of an inverter control system according to an exemplary embodiment;

[0059] Figure 8 is a block diagram of an inverter control module according to an exemplary embodiment. DETAILED DESCRIPTION

[0060] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0061] Figure 1 FIG. 1 is a flow chart of an inverter control method according to an exemplary embodiment. Figure 1 As shown (steps 101-104 represent steps 1 to 4 respectively), the method may include the following steps:

[0062] Step 101, obtaining a target voltage corresponding to the inverter, and a first output voltage and a first output current of the current inverter.

[0063] For example, in order to reduce the impact current generated when starting the inverter, the output voltage of the inverter can be smoothly adjusted to ensure that the output voltage of the inverter will not increase or decrease suddenly during the startup process, so that the output voltage of the inverter can transition linearly and smoothly from zero to the voltage value required by the load, thereby reducing the impact current generated when the inverter is started.

[0064] Specifically, first, the target voltage corresponding to the inverter, as well as the first output voltage and the first output current of the current inverter can be obtained. Among them, the target voltage can be preset or set by the user by sending corresponding instructions. The target voltage can be understood as the voltage that the inverter needs to provide to the load. The target voltage can include a direct-axis target voltage and a quadrature-axis target voltage. The direct-axis target voltage is the voltage on the d-axis (i.e., the direct axis) of the dq0 rotating coordinate system, and the quadrature-axis target voltage is the voltage on the q-axis (i.e., the quadrature axis) of the dq0 rotating coordinate system. The first output voltage is the output voltage of the inverter collected in real time during the startup of the inverter, and the first output current is the output current of the inverter collected in real time during the startup of the inverter.

[0065] Step 102, determining a first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage, where the historical given voltage is the first target given voltage at the previous moment.

[0066] Further, in order to make the output voltage of the inverter smoothly transition to the target voltage, a smooth given method can be used to set different first target given voltages at different times in time sequence (for example, different first target given voltages can be set at 0s, 2s, 4s, ..., 10s respectively), and the inverter is made to adjust the output voltage of the inverter according to the first target given voltage set each time. Among them, each moment corresponds to a first target given voltage, and the first target given voltage is the voltage value to which the output voltage of the inverter is to be adjusted in the time period from the moment to the next moment. By setting different first target given voltages at different moments, it is equivalent to dividing the original need to adjust the output voltage of the inverter to the target voltage at one time into multiple step-by-step adjustment stages, each adjustment stage corresponds to a moment, and each adjustment stage includes the time period from the moment corresponding to the adjustment stage to the moment corresponding to the next adjustment stage. The first target given voltage includes a first straight axis given voltage and a first quadrature axis given voltage, the first straight axis given voltage is the voltage on the d axis, and the first quadrature axis given voltage is the voltage on the q axis. For example, the first target given voltage at the current moment may be determined according to the target voltage, the historical given voltage and the preset step voltage. The current moment is the moment corresponding to the current regulation stage of the inverter.

[0067] Specifically, after obtaining the target voltage, when the target voltage is greater than the historical given voltage, and the difference between the target voltage and the historical given voltage is greater than or equal to the step voltage, the sum of the historical given voltage and the step voltage can be used as the first target given voltage. Taking the time of setting the first target given voltage as 0s, 2s, and 4s, the target voltage is 60V, and the step voltage is 20V as an example, if the current time is 0s, there is no historical given voltage at this time, the historical given voltage is set to 0, then the difference between the target voltage and the historical given voltage is: 60-0=60V>20V, then the first target given voltage corresponding to 0s is determined to be: 0+20V=20V. If the current time is 2s, the historical given voltage at this time is the first target given voltage corresponding to 0s, then the historical given voltage is set to 20V, then the difference between the target voltage and the historical given voltage is: 60-20=40V>20V, then the first target given voltage corresponding to 2s is: 20+20V=40V.

[0068] Alternatively, when the target voltage is greater than the historical given voltage and the difference between the target voltage and the historical given voltage is less than the step voltage, the target voltage can be used as the first target given voltage. Alternatively, when the target voltage is less than or equal to the historical given voltage and the difference between the historical given voltage and the target voltage is greater than or equal to the step voltage, the difference between the historical given voltage and the step voltage can be used as the first target given voltage. Alternatively, when the target voltage is less than or equal to the historical given voltage and the difference between the historical given voltage and the target voltage is less than the step voltage, the target voltage can be used as the first target given voltage.

[0069] Step 103: adjusting the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage.

[0070] For example, the first target current can be determined according to the first target given voltage and the first output voltage, and the first reference voltage can be determined according to the first target current and the first output current. For example, the difference between the first target given voltage and the first output voltage can be used as the input of a voltage PI (English: Proportional Iintegral, Chinese: proportional integral) regulator, and the difference between the output of the voltage PI regulator and the first output current can be used as the input of a current PI regulator, and the first reference voltage can be obtained according to the output of the current PI regulator in combination with inductor feedforward decoupling.

[0071] Then, the output voltage of the inverter can be adjusted according to the first reference voltage. For example, the first reference voltage can be PWM modulated to obtain a drive signal corresponding to the first reference voltage, and the output voltage of the inverter can be adjusted according to the drive signal.

[0072] Step 104 , determining whether the difference between the adjusted output voltage of the inverter and the target voltage is not greater than a first preset voltage difference.

[0073] If yes, the inverter is controlled to start up.

[0074] If not, the above steps are repeated until the difference between the adjusted output voltage of the inverter and the target voltage is not greater than the first preset voltage difference, so as to control the inverter to complete startup.

[0075] For example, after adjusting the output voltage of the inverter, it can be determined whether the difference between the output voltage of the adjusted inverter and the target voltage is not greater than the first preset voltage difference. If the difference between the output voltage of the adjusted inverter and the target voltage is not greater than the first preset voltage difference (for example, 10V), the inverter is controlled to complete startup. If the difference between the output voltage of the adjusted inverter and the target voltage is greater than the first preset voltage difference, it means that the adjustment of the output voltage of the inverter this time does not meet the startup requirements of the inverter. The above steps can be repeated to adjust the output voltage of the inverter again until the difference between the output voltage of the inverter and the target voltage is not greater than the first preset voltage difference, so as to complete the startup of the inverter.

[0076] In summary, the present invention obtains the target voltage corresponding to the inverter, as well as the first output voltage and the first output current of the current inverter, and determines the first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage, wherein the historical given voltage is the first target given voltage at the previous moment, and then adjusts the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage, and determines whether the difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference. If so, the inverter is controlled to complete the startup, and if not, the above steps are repeated until the difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference, so as to control the inverter to complete the startup. The present invention adjusts the first target given voltage multiple times by the step voltage, and adjusts the output voltage of the inverter by the first target given voltage after each adjustment, so that the output voltage of the inverter can smoothly transition to the target voltage, reduce the impact current generated by the inverter startup, and cause less impact on the load, so as to avoid damage to the inverter and extend the service life of the inverter.

[0077] Optionally, determining the first target current according to the first target given voltage and the first output voltage, and determining the first reference voltage according to the first target current and the first output current can be achieved by the following steps:

[0078] Step A), performing proportional-integral adjustment on the difference between the first target given voltage and the first output voltage to obtain the first target current.

[0079] Step B), performing proportional-integral adjustment on the difference between the first target current and the first output current to obtain a first voltage.

[0080] Step C), performing feed-forward decoupling on the first output current to obtain a second voltage.

[0081] Step D), determining a first reference voltage according to the first voltage and the second voltage.

[0082] For example, the first output voltage and the first output current are both three-phase symmetrical sinusoidal quantities in the abc coordinate system. Figure 2 As shown, we can first use the Parker transformation (i.e. Figure 2 The first output voltage is transformed by using abc / dq in the formula (abc / dq) to obtain a first direct-axis output voltage Ud1 of the first output voltage on the d-axis, and a first quadrature-axis output voltage Uq1 of the first output voltage on the q-axis, and the first output current is transformed by using a Park transformation to obtain a first direct-axis output current Id1 of the first output current on the d-axis, and a first quadrature-axis output current Iq1 of the first output current on the q-axis.

[0083] Then, the difference between Ud1_obj (Ud1_obj is the first direct-axis given voltage) and Ud1 can be sent to the first outer-loop PI regulator for proportional-integral regulation to obtain the first direct-axis given current Id1_obj included in the first target current. At the same time, the difference between Uq_obj (Uq1_obj is the first quadrature-axis given voltage) and Uq1 can be sent to the second outer-loop PI regulator for proportional-integral regulation to obtain the first quadrature-axis given current Iq1_obj included in the first target current. After that, the difference between Id1_obj and Id1 can be sent to the first inner-loop PI regulator for proportional-integral regulation to obtain the first direct-axis voltage U'd1 included in the first voltage. At the same time, the difference between Iq1_obj and Iq1 can be sent to the second inner-loop PI regulator for proportional-integral regulation to obtain the first quadrature-axis voltage U'q1 included in the first voltage. In addition, Id1 and Iq1 can be decoupled by inductive feedforward (i.e., by Figure 2 wL in the feedforward decoupling) to obtain a second voltage, the second voltage includes a second direct-axis voltage U'd2 and a second quadrature-axis voltage U'q2. Finally, the first reference voltage can be determined according to the first voltage and the second voltage. The first reference voltage includes a first direct-axis reference voltage Ud1_ref and a first quadrature-axis reference voltage Uq1_ref, Ud1_ref = U'd1 + U'd2, Uq1_ref = U'q1 + U'q2. After determining the first reference voltage, the first reference voltage can be subjected to an inverse Park transformation (i.e. Figure 2 dq / abc in the inverse transformation), and PWM modulation is performed on the inverse transformed first reference voltage, and the inverter is driven according to the obtained PWM signal.

[0084] Figure 3 FIG. 1 is a flow chart of another inverter control method according to an exemplary embodiment. Figure 3 As shown, there are multiple inverters, each inverter communicates with each other, and after all inverters are started, the method further includes the following steps:

[0085] Step 105: Obtain the active power and reactive power output by each inverter.

[0086] Step 106: determine the average active power according to the active power output by each inverter, and determine the average reactive power according to the reactive power output by each inverter.

[0087] In another scenario, after each inverter is started, in order to reduce the circulating current between the inverters, the active power (P1, P2, ..., Pn) and reactive power (Q1, Q2, ..., Qn) output by each inverter can be obtained, where n is the number of inverters. Then, the average active power P_avg of all inverters can be determined based on the active power output by each inverter, and the average reactive power Q_avg of all inverters can be determined based on the reactive power output by each inverter. Wherein, P_avg = (P1+P2+...+Pn) / n, Q_avg = (Q1+Q2+...+Qn) / n.

[0088] Step 107, obtaining the second output voltage and the second output current of the current inverter.

[0089] Step 108, adjusting the output voltage of the inverter according to the target voltage, the second output voltage, the second output current, the average active power and the average reactive power, so that the output voltage difference between the multiple inverters is not greater than the second preset voltage difference.

[0090] For example, after each inverter is started, the second output voltage and the second output current of each inverter can be obtained. Then, the second target given voltage can be determined according to the active power, reactive power, average active power, average reactive power and target voltage output by the inverter. Then, the second target current is determined according to the second target given voltage and the second output voltage, and the second reference voltage is determined according to the second target current and the second output current. Finally, the output voltage of the inverter is adjusted according to the second reference voltage.

[0091] Specifically, for each inverter, the second target given voltage of the inverter can be determined according to the active power Pi, reactive power Qi, average active power P_avg, average reactive power Q_avg and target voltage output by the inverter. For example, the difference between Pi and P_avg can be sent to the first power PI regulator to obtain the direct-axis correction voltage ΔUd. At the same time, the difference between Qi and Q_avg can be sent to the second power PI regulator to obtain the quadrature-axis correction voltage ΔUq. Then, the second target given voltage can be determined according to ΔUd, ΔUq and the target voltage. Among them, the second target given voltage includes the second direct-axis given voltage Ud2_obj and the second quadrature-axis given voltage Uq2_obj, Ud2_obj=ΔUd+Ud0, Uq2_obj=ΔUq+Uq0, Ud0 is the direct-axis target voltage, and Uq0 is the quadrature-axis target voltage. Then, the second target current of the inverter can be determined according to the second target given voltage and the second output voltage of the inverter, and the second reference voltage of the inverter can be determined according to the second target current and the second output current of the inverter. Finally, the output voltage of the inverter can be adjusted according to the second reference voltage of the inverter so that the output voltage difference between the multiple inverters is not greater than the second preset voltage difference, which can be, for example, 1V.

[0092] Optionally, determining the second target current according to the second target given voltage and the second output voltage, and determining the second reference voltage according to the second target current and the second output current can be achieved by the following steps:

[0093] Step a), performing proportional-integral adjustment on the difference between the second target given voltage and the second output voltage to obtain a second target current.

[0094] Step b) performs proportional-integral adjustment on the difference between the second target current and the second output current to obtain a third voltage.

[0095] Step c), performing feed-forward decoupling on the second output current to obtain a fourth voltage.

[0096] Step d), determining a second reference voltage according to the third voltage and the fourth voltage.

[0097] For example, the control flow diagram after the inverter is started can be as follows: Figure 4 As shown, the second output voltage can be transformed by Park transformation to obtain a second direct-axis output voltage Ud2 of the second output voltage on the d-axis, and a second quadrature-axis output voltage Uq2 of the second output voltage on the q-axis, and the second output current can be transformed by Park transformation to obtain a second direct-axis output current Id2 of the second output current on the d-axis, and a second quadrature-axis output current Iq2 of the first output current on the q-axis.

[0098] Then the difference between Ud2_obj and Ud2 can be sent to the first outer loop PI regulator for proportional integral regulation to obtain the second direct axis given current Id2_obj included in the second target current. At the same time, the difference between Uq2_obj and Uq2 can be sent to the second outer loop PI regulator for proportional integral regulation to obtain the second quadrature axis given current Iq2_obj included in the second target current. After that, the difference between Id2_obj and Id2 can be sent to the first inner loop PI regulator for proportional integral regulation to obtain the third direct axis voltage U'd3 included in the third voltage. At the same time, the difference between Iq2_obj and Iq2 can be sent to the second inner loop PI regulator for proportional integral regulation to obtain the third quadrature axis voltage U'q3 included in the third voltage. In addition, Id2 and Iq2 can be respectively decoupled by inductive feedforward to obtain the fourth voltage, which includes the fourth direct axis voltage U'd4 and the fourth quadrature axis voltage U'q4. Finally, the second reference voltage can be determined based on the third voltage and the fourth voltage. The second reference voltage includes a second direct-axis reference voltage Ud2_ref and a second quadrature-axis reference voltage Uq2_ref, Ud2_ref=U'd3+U'd4, Uq2_ref=U'q3+U'q4. After determining the second reference voltage, the first reference voltage can be subjected to an inverse Park transformation, and the inversely transformed second reference voltage can be subjected to PWM modulation, and the inverter can be driven according to the obtained PWM signal.

[0099] Figure 5 FIG. 1 is a flow chart of another inverter control method according to an exemplary embodiment. Figure 5 As shown, before step 105, the method may further include:

[0100] Step 109, obtaining the operating status of each inverter, where the operating status includes a normal state or an abnormal state.

[0101] Step 110: determining a master inverter among multiple inverters according to the operating status.

[0102] In one scenario, the operating status of each inverter can be obtained in real time. The operating status includes a normal state or an abnormal state. The normal state is used to indicate that the inverter has no faults and can work normally. The abnormal state is used to indicate that the inverter has faults and cannot work normally.

[0103] Then, an inverter can be selected from the inverters in normal operation as the master inverter, and the other inverters can be used as slave inverters. Furthermore, the master inverter is not fixed to a certain inverter. Once the master inverter fails, the control module can select another inverter from the inverters in normal operation as the master inverter. In this way, redundancy can be increased, thereby ensuring the reliability of synchronization.

[0104] Step 111, synchronizing the frequency and phase of the output voltage of the slave inverter according to the synchronization signal generated by the master inverter, the synchronization signal includes the frequency and phase of the output voltage of the master inverter, and the slave inverter is any inverter except the master inverter.

[0105] Specifically, the master inverter may periodically generate a synchronization signal including the frequency and phase of the output voltage of the master inverter, and the synchronization signal may be, for example, a square wave signal. Then, the frequency and phase of the output voltage of each slave inverter may be synchronized according to the frequency and phase of the output voltage included in the synchronization signal, so that the frequency and phase of the output voltage of each slave inverter are synchronized with the frequency and phase of the output voltage of the master inverter.

[0106] In summary, the present invention obtains the target voltage corresponding to the inverter, as well as the first output voltage and the first output current of the current inverter, and determines the first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage, wherein the historical given voltage is the first target given voltage at the previous moment, and then adjusts the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage, and determines whether the difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference. If so, the inverter is controlled to complete the startup, and if not, the above steps are repeated until the difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference, so as to control the inverter to complete the startup. The present invention adjusts the first target given voltage multiple times by the step voltage, and adjusts the output voltage of the inverter by the first target given voltage after each adjustment, so that the output voltage of the inverter can smoothly transition to the target voltage, reduce the impact current generated by the inverter startup, and cause less impact on the load, so as to avoid damage to the inverter and extend the service life of the inverter.

[0107] Figure 6 FIG. 1 is a block diagram of an inverter control device according to an exemplary embodiment. Figure 6 As shown, the inverter control device 200 includes:

[0108] Memory 201.

[0109] Processor 202, the processor 202 is used for any one of the above inverter control methods.

[0110] Regarding the inverter control device 200 in the above embodiment, the specific manner in which the processor 202 performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0111] The present disclosure also relates to an inverter control system, such as Figure 7 As shown ( Figure 7 Taking four inverter modules 301 as an example, the system 300 includes: a plurality of inverter modules 301 , the inverter control device 200 , and a load 302 .

[0112] The multiple inverter modules 301 are interconnected and communicated with each other, the inverter control device 200 is connected to the multiple inverter modules 301, and the multiple inverter modules 301 are respectively connected to the load 302. The load 302 can be, for example, a battery, an energy storage system, a motor, and various types of electrical equipment.

[0113] It should be noted that Figure 7 The multiple inverter modules 301 are interconnected and communicated with each other through synchronous optical fibers, and the inverter control device 200 is connected to the multiple inverter modules 301 through a communication bus. This is just an example of the inverter control system 300, and the present disclosure does not limit the specific connection method of the inverter control system 300.

[0114] Further, such as Figure 8As shown, the inverter module 301 may include a battery 3011, an inverter 3012, a filter 3013, a sampling circuit 3014, and a controller 3015. The battery 3011 is used as a DC power supply of the inverter module 301, and is connected to the DC side of the inverter 3012 to provide DC power to the inverter 3012. The AC side of the inverter 3012 is connected to the input side of the filter 3013, and the output side of the filter 3013 is connected to the load 302. The inverter 3012 may include high-power power electronic devices such as IGBT (Insulated Gate Bipolar Transistor, Chinese: Insulated Gate Bipolar Transistor) and AC-DC conversion circuits. The filter 3013 is used to perform EMC (Electromagnetic Compatibility, Chinese: Electromagnetic Compatibility) filtering on the AC output of the inverter 3012 to filter out the harmonic components in the AC output of the inverter 3012. The sampling circuit 3014 may include a current detection circuit and a voltage detection circuit. The current detection circuit is used to detect the output current of the inverter 3012, and the voltage detection circuit is used to detect the output voltage of the filter 3013 (i.e., the output voltage of the inverter 3012). The sampling circuit 3014 is connected to the controller 3015. The controller 3015 is connected to the control end of the inverter 3012, and is used to generate a PWM (English: Pulse width modulation, Chinese: Pulse width modulation) signal to adjust the output of the inverter 3012 through the PWM signal. The controller 3015 may, for example, use a high-performance real-time signal processor such as a DSP (English: Digital Signal Process, Chinese: Digital Signal Processing), an FPGA (English: Field Programmable Gate Array, Chinese: Field Programmable Logic Gate Array Foreign Name).

[0115] It should be noted that the above-mentioned control process of starting the inverter 3012 and the control process after the inverter 3012 is started can be implemented by the inverter control device 200, or by the controller 3015, or by the inverter control device 200 and the controller 3015 together.

[0116] In summary, the present invention obtains the target voltage corresponding to the inverter, as well as the first output voltage and the first output current of the current inverter, and determines the first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage, wherein the historical given voltage is the first target given voltage at the previous moment, and then adjusts the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage, and determines whether the difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference. If so, the inverter is controlled to complete the startup, and if not, the above steps are repeated until the difference between the output voltage of the inverter after adjustment and the target voltage is not greater than the first preset voltage difference, so as to control the inverter to complete the startup. The present invention adjusts the first target given voltage multiple times by the step voltage, and adjusts the output voltage of the inverter by the first target given voltage after each adjustment, so that the output voltage of the inverter can smoothly transition to the target voltage, reduce the impact current generated by the inverter startup, and cause less impact on the load, so as to avoid damage to the inverter and extend the service life of the inverter.

[0117] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0118] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0119] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. An inverter control method, characterized in that: The method comprises: Step 1: Obtaining a target voltage corresponding to the inverter, and a first output voltage and a first output current of the inverter; Step 2: Determine the first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage, wherein the historical given voltage is the first target given voltage at the previous moment; Step three: adjusting the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage; Step 4: Determine whether the difference between the adjusted output voltage of the inverter and the target voltage is not greater than a first preset voltage difference. If yes, the inverter is controlled to start up. If not, repeat steps 1 to 4 until the difference between the adjusted output voltage of the inverter and the target voltage is no greater than the first preset voltage difference, so as to control the inverter to start up; Determining the first target given voltage at the current moment according to the target voltage, the historical given voltage and the preset step voltage includes: When the target voltage is greater than the historical given voltage, and the difference between the target voltage and the historical given voltage is greater than or equal to the step voltage, the sum of the historical given voltage and the step voltage is used as the first target given voltage; When the target voltage is greater than the historical given voltage and the difference between the target voltage and the historical given voltage is less than the step voltage, the target voltage is used as the first target given voltage; When the target voltage is less than or equal to the historical given voltage, and the difference between the historical given voltage and the target voltage is greater than or equal to the step voltage, the difference between the historical given voltage and the step voltage is used as the first target given voltage; When the target voltage is less than or equal to the historical given voltage, and the difference between the historical given voltage and the target voltage is less than the step voltage, the target voltage is used as the first target given voltage.

2. The method according to claim 1, characterized in that The step of adjusting the output voltage of the inverter according to the first output voltage, the first output current and the first target given voltage includes: Determine a first target current according to the first target given voltage and the first output voltage, and determine a first reference voltage according to the first target current and the first output current; The output voltage of the inverter is adjusted according to the first reference voltage.

3. The method according to claim 2, characterized in that The determining a first target current according to the first target given voltage and the first output voltage, and determining a first reference voltage according to the first target current and the first output current, comprises: Performing proportional-integral adjustment on the difference between the first target given voltage and the first output voltage to obtain the first target current; Performing proportional-integral adjustment on the difference between the first target current and the first output current to obtain a first voltage; performing feed-forward decoupling on the first output current to obtain a second voltage; The first reference voltage is determined according to the first voltage and the second voltage.

4. The method according to claim 1, characterized in that There are multiple inverters, each of which communicates with each other. After all the inverters are started, the method further includes: Obtaining active power and reactive power output by each of the inverters; Determine the average active power according to the active power output by each of the inverters, and determine the average reactive power according to the reactive power output by each of the inverters; Obtaining a second output voltage and a second output current of the inverter; The output voltage of the inverter is adjusted according to the target voltage, the second output voltage, the second output current, the average active power and the average reactive power so that the output voltage difference between the multiple inverters is not greater than a second preset voltage difference.

5. The method according to claim 4, characterized in that The step of adjusting the output voltage of the inverter according to the target voltage, the second output voltage, the second output current, the average active power and the average reactive power includes: Determining a second target given voltage according to the active power, the reactive power, the average active power, the average reactive power and the target voltage output by the inverter; Determine a second target current according to the second target given voltage and the second output voltage, and determine a second reference voltage according to the second target current and the second output current; The output voltage of the inverter is adjusted according to the second reference voltage.

6. The method according to claim 5, characterized in that The determining of a second target current according to the second target given voltage and the second output voltage, and determining a second reference voltage according to the second target current and the second output current, comprises: Performing proportional-integral adjustment on the difference between the second target given voltage and the second output voltage to obtain the second target current; Performing proportional-integral adjustment on the difference between the second target current and the second output current to obtain a third voltage; Performing feed-forward decoupling on the second output current to obtain a fourth voltage; The second reference voltage is determined according to the third voltage and the fourth voltage.

7. The method according to claim 4, characterized in that Before acquiring the active power and reactive power output by each inverter, the method further includes: Acquire the operating state of each of the inverters, where the operating state includes a normal state or an abnormal state; Determining a master inverter among the plurality of inverters according to the operating status; The frequency and phase of the output voltage of the slave inverter are synchronized according to the synchronization signal generated by the master inverter, wherein the synchronization signal includes the frequency and phase of the output voltage of the master inverter, and the slave inverter is any inverter except the master inverter.

8. An inverter control device, characterized in that: The inverter control device comprises: Memory; A processor configured to execute the method according to any one of claims 1 to 7.

9. An inverter control system, characterized in that: include: A plurality of inverter modules, wherein the plurality of inverter modules are interconnected and communicate with each other, and each of the inverter modules comprises an inverter; The inverter control device as claimed in claim 8, wherein the inverter control device is connected to a plurality of the inverter modules; A load, wherein the plurality of inverter modules are connected to the loads respectively.

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