Converter starting control method, device and system, converter and air conditioning system

Abstract

The invention relates to a converter starting control method, device and system, a converter and an air conditioning system. The converter starting control method comprises the steps of determining a working mode of a converter according to whether at least one of a photovoltaic system and an energy storage system is connected to the converter; in the working mode, a bus capacitor of the converter is charged through a resistor, and a bus voltage is established; determining the angle compensation amount and the voltage compensation amount of the working mode according to the value of the bus voltage and the amplitude, the phase and the frequency of the power grid voltage; and according to the angle compensation amount and the voltage compensation amount of the working mode, compensating the current starting angle and the current starting voltage of the converter, and starting the converter according to the compensated angle and the compensated voltage. According to the invention, the voltage angle and amplitude can be corrected according to different working modes of the converter, so that the starting peak can be reduced, the starting current impact can be reduced, and the stable starting of the converter can be realized.

Description

Technical Field

[0001] The present disclosure relates to the field of inverters, and in particular to a method, device and system for controlling start-up of an inverter, an inverter and an air-conditioning system. Background Art

[0002] With the development of photovoltaic air conditioners and energy routers, the core controller converter needs to establish a controllable DC bus voltage at the start-up stage. When establishing the DC bus voltage, the voltage and frequency of the detected grid lag in the control sequence, resulting in deviations from the voltage and frequency of the actual grid. When the grid is connected with deviations, current spikes are likely to occur, affecting grid stability. Summary of the invention

[0003] The inventors have found through research that the related technology is to compensate for the deviation by manual calculation, and to compensate after artificially determining the deviation of voltage and frequency. However, the related technology method requires calculation and compensation for each machine, which wastes manpower and time.

[0004] In view of at least one of the above technical problems, the present disclosure provides a converter starting control method, device and system, converter and air-conditioning system, which can correct the voltage angle and amplitude according to different working modes of the converter, thereby reducing the starting peak and reducing the starting current impact.

[0005] According to one aspect of the present disclosure, there is provided a converter startup control method, comprising:

[0006] determining a working mode of the converter according to whether at least one of the photovoltaic system and the energy storage system is connected to the converter;

[0007] In the working mode, the bus capacitor of the converter is charged through the resistor to establish the bus voltage;

[0008] Determining the angle compensation amount and the voltage compensation amount of the working mode according to the value of the bus voltage, the amplitude, phase and frequency of the grid voltage;

[0009] According to the angle compensation amount and the voltage compensation amount of the working mode, the current angle and the current voltage of the converter at startup are compensated, and the converter is started according to the compensated angle and the compensated voltage.

[0010] In some embodiments of the present disclosure, determining the working mode of the converter according to whether at least one of the photovoltaic system and the energy storage system is connected to the converter comprises at least one of the following steps:

[0011] When the photovoltaic system is connected to the converter, determining that the working mode of the converter is the first working mode;

[0012] When the photovoltaic system is not connected to the converter and the energy storage system is connected to the converter, determining that the working mode of the converter is the second working mode;

[0013] When the photovoltaic system is not connected to the converter and the energy storage system is not connected to the converter, the operating mode of the converter is determined to be the third operating mode.

[0014] In some embodiments of the present disclosure, in the working mode, charging the bus capacitor of the converter through a resistor to establish the bus voltage includes at least one of the following steps:

[0015] In the first working mode, the photovoltaic system is used to charge the bus capacitor of the converter through a resistor to establish a bus voltage;

[0016] In the second working mode, the energy storage system is used to charge the bus capacitor of the converter through a resistor to establish a bus voltage;

[0017] In the third working mode, the grid voltage is used to charge the bus capacitor of the converter through a resistor to establish the bus voltage.

[0018] In some embodiments of the present disclosure, charging the bus capacitor of the converter through a resistor using a photovoltaic system to establish a bus voltage includes:

[0019] Determine whether the current photovoltaic voltage is within a predetermined photovoltaic voltage range;

[0020] When the current photovoltaic voltage is within the predetermined photovoltaic voltage range, the first charging switch is closed to charge the bus capacitor of the converter through the resistance of the photovoltaic system;

[0021] Detect whether the bus voltage is established;

[0022] When the bus voltage is established, the first working switch is closed and the converter outputs an inverter voltage.

[0023] In some embodiments of the present disclosure, the step of using the energy storage system to charge the bus capacitor of the converter through a resistor to establish the bus voltage includes:

[0024] Determine whether the energy storage charge state is within a predetermined range;

[0025] When the energy storage charge state is within a predetermined range, the second charging switch is closed, and the bus capacitor of the converter is charged by the energy storage system through a resistor;

[0026] Detect whether the bus voltage is established;

[0027] When the bus voltage is established, the second working switch is closed and the converter outputs an inverter voltage.

[0028] In some embodiments of the present disclosure, charging the bus capacitor of the converter by using the grid voltage through a resistor to establish the bus voltage includes:

[0029] determining whether the AC voltage is within a predetermined voltage range;

[0030] When the AC voltage is within a predetermined voltage range, the third charging switch is closed to charge the bus capacitor of the converter via a resistor using the grid voltage;

[0031] Detect whether the bus voltage is established;

[0032] When the bus voltage is established, the third working switch is closed and the converter outputs an inverter voltage.

[0033] In some embodiments of the present disclosure, compensating the current angle and current voltage of the converter at startup according to the angle compensation amount and the voltage compensation amount of the working mode, and starting the converter according to the compensated angle and the compensated voltage includes:

[0034] When the angle compensation amount is zero and the voltage compensation amount is zero, starting the converter according to the current angle and voltage at which the converter is started;

[0035] When the angle compensation amount is not zero and the voltage compensation amount is not zero, the starting angle of the converter is compensated according to the angle compensation amount of the working mode, and the starting voltage of the converter is compensated according to the voltage compensation amount of the working mode, and the converter is started according to the compensated angle and voltage.

[0036] In some embodiments of the present disclosure, compensating the current angle and current voltage of the converter at startup according to the angle compensation amount and the voltage compensation amount of the working mode, and starting the converter according to the compensated angle and the compensated voltage includes:

[0037] When the angle compensation amount is zero and the voltage compensation amount is not zero, the voltage at which the converter is started is compensated according to the voltage compensation amount of the working mode, and the converter is started according to the current angle at which the converter is started and the compensated voltage;

[0038] When the angle compensation amount is not zero and the voltage compensation amount is zero, the starting angle of the converter is compensated according to the angle compensation amount of the working mode, and the converter is started according to the current starting voltage of the converter and the compensated angle.

[0039] In some embodiments of the present disclosure, determining the angle compensation amount and the voltage compensation amount of the working mode according to the value of the bus voltage, the amplitude, phase and frequency of the grid voltage includes:

[0040] Obtain the amplitude, phase and frequency of the grid voltage;

[0041] The amplitude, phase and frequency of the grid voltage are used as the target amplitude, target phase and target frequency of the inverter voltage;

[0042] generating the inverter voltage according to the bus voltage, and the target amplitude, target phase and target frequency of the inverter voltage;

[0043] Obtaining the actual amplitude and actual phase of the inverter voltage;

[0044] An angle compensation amount and a voltage compensation amount are determined according to the actual amplitude and actual phase of the inverter voltage and the amplitude and phase of the grid voltage.

[0045] In some embodiments of the present disclosure, generating the inverter voltage according to the bus voltage, and the target amplitude, target phase, and target frequency of the inverter voltage includes:

[0046] Determining an inverter modulation wave required to generate the inverter voltage according to the bus voltage, the target amplitude, the target phase and the target frequency of the inverter voltage;

[0047] The inverter voltage is generated according to the bus voltage and the inverter modulation wave.

[0048] According to another aspect of the present disclosure, there is provided a control device, comprising:

[0049] A working mode determination module is configured to determine a working mode of the converter according to whether at least one of the photovoltaic system and the energy storage system is connected to the converter;

[0050] A bus voltage establishing module is configured to charge the bus capacitor of the converter through a resistor to establish a bus voltage in the working mode;

[0051] A compensation amount determination module is configured to determine an angle compensation amount and a voltage compensation amount of the working mode according to the value of the bus voltage, the amplitude, phase and frequency of the grid voltage;

[0052] The starting control module is configured to compensate the current angle and current voltage of the converter at startup according to the angle compensation amount and voltage compensation amount of the working mode, and start the converter according to the compensated angle and compensated voltage.

[0053] According to another aspect of the present disclosure, there is provided a control device, comprising:

[0054] a memory configured to store instructions; and

[0055] The processor is configured to execute the instructions so that the control device implements the converter startup control method as described in any of the above embodiments.

[0056] According to another aspect of the present disclosure, a converter startup control system is provided, comprising a control device as described in any of the above embodiments.

[0057] In some embodiments of the present disclosure, the converter startup control system further includes:

[0058] A photovoltaic system access control circuit, wherein the photovoltaic system access control circuit includes a first charging switch, a first resistor and a first working switch, the first charging switch and the first resistor are connected in series and then in parallel with the first working switch, the first charging switch is configured to, when closed, allow the photovoltaic system to charge the bus capacitor of the converter through the first resistor, and the first working switch is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0059] In some embodiments of the present disclosure, the converter startup control system further includes:

[0060] The energy storage system access control circuit includes a second charging switch, a second resistor and a second working switch, the second charging switch and the second resistor are connected in series and then connected in parallel with the second working switch, the second charging switch is configured to, when closed, allow the energy storage system to charge the bus capacitor of the converter through the second resistor, and the second working switch is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0061] In some embodiments of the present disclosure, the converter startup control system further includes:

[0062] A power grid access control circuit, wherein the power grid access control circuit includes a first rectifier, a third charging switch, a third resistor and a third working switch, the first rectifier is configured to convert the power grid AC voltage into a DC voltage, the third charging switch and the third resistor are connected in series and in parallel with the third working switch, the third charging switch is configured to, when closed, allow the power grid voltage to charge the bus capacitor of the converter through the first rectifier and the third resistor, and the third working switch is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0063] In some embodiments of the present disclosure, the converter startup control system further includes:

[0064] A first acquisition module is configured to acquire bus voltage;

[0065] The second acquisition module is configured to acquire the amplitude, phase and frequency of the grid voltage;

[0066] The third acquisition module is configured to acquire the actual amplitude, actual phase and actual frequency of the inverter voltage.

[0067] In some embodiments of the present disclosure, the converter startup control system further includes:

[0068] An AC switch, wherein the AC switch is arranged between the power grid and the converter; a second acquisition module is configured to collect the amplitude, phase and frequency of the power grid voltage between the power grid and the AC switch; and a third acquisition module is configured to collect the actual amplitude, actual phase and actual frequency of the inverter voltage between the AC switch and the converter.

[0069] According to another aspect of the present disclosure, a converter system is provided, comprising the converter startup control system as described in any one of the above embodiments.

[0070] According to another aspect of the present disclosure, an air conditioning system is provided, comprising the inverter system as described in any of the above embodiments.

[0071] According to another aspect of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and when the instructions are executed by a processor, the converter startup control method as described in any of the above embodiments is implemented.

[0072] According to another aspect of the present disclosure, a computer program product is provided, including a computer program, wherein when the computer program is executed by a processor, the converter startup control method as described in any of the above embodiments is implemented.

[0073] The present disclosure can correct the voltage angle and amplitude according to different working modes of the converter, thereby reducing the starting peak and the starting current impact, thereby achieving stable starting of the converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0075] Figure 1 Schematic diagram of the multi-mode converter system.

[0076] Figure 2 Schematic diagram of some embodiments of the converter startup control method disclosed in the present invention.

[0077] Figure 3 Schematic diagram of some embodiments of the converter startup control system disclosed in the present invention.

[0078] Figure 4 Schematic diagrams of other embodiments of the converter startup control method disclosed in the present invention.

[0079] Figure 5 Schematic diagram of the structure of some embodiments of the control device disclosed in the present invention.

[0080] Figure 6 Schematic diagram of the structure of other embodiments of the control device disclosed in the present invention.

[0081] Figure 7 Schematic diagrams of other embodiments of the converter startup control system disclosed in the present invention. DETAILED DESCRIPTION

[0082] The technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0083] Unless specifically stated otherwise, the relative arrangement of components and steps, the numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure.

[0084] At the same time, it should be understood that for the convenience of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship.

[0085] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0086] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0087] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0088] The inventors found through research that: Figure 1Figure 1 is a schematic diagram of the multi-mode converter system. Figure 1 As shown, the interfaces of the converter in the related technology are connected to photovoltaic and energy storage, and are not connected to photovoltaic and energy storage. The engineering application conditions are complex and uncertain. The related technology does not have a bus establishment method and startup control method for converter application systems in different situations.

[0089] The present disclosure proposes a unified busbar establishment method and a grid voltage and frequency compensation system for converter application systems in different situations. The present disclosure is described below through specific embodiments.

[0090] Figure 2 Schematic diagram of some embodiments of the converter startup control method disclosed in the present invention. Figure 2 The embodiment can be executed by the inverter startup control device of the present disclosure, the inverter startup control system of the present disclosure, the inverter system of the present disclosure, or the air conditioning system of the present disclosure. Figure 2 As shown, Figure 2 The method of the embodiment may include at least one of steps 1 to 4.

[0091] Step 1: Determine the working mode of the converter according to whether at least one of the photovoltaic system and the energy storage system is connected to the converter.

[0092] In some embodiments of the present disclosure, step 1 may include at least one of steps 11 to 13, and the order of steps 11 to 13 may be adjusted.

[0093] Step 11: when the photovoltaic system is connected to the inverter, determine that the working mode of the inverter is the first working mode.

[0094] The above embodiments of the present disclosure give photovoltaics a higher priority. When both photovoltaics and energy storage are connected, the photovoltaic system is used to charge the bus capacitor of the converter through a resistor to establish a bus voltage. This can fully utilize the photovoltaic power generation and better achieve energy saving and energy storage of the energy storage system.

[0095] Step 12: When the photovoltaic system is not connected to the converter and the energy storage system is connected to the converter, determine that the operating mode of the converter is the second operating mode.

[0096] Step 13: When the photovoltaic system is not connected to the converter and the energy storage system is not connected to the converter, determine that the operating mode of the converter is the third operating mode.

[0097] The above embodiments of the present disclosure distinguish different working modes according to whether photovoltaic and energy storage are connected. Therefore, the present disclosure can use different power sources (photovoltaic system, energy storage system and AC power supply) to charge the bus capacitor according to different working modes, thereby improving the adaptability of the system and also improving the energy saving effect.

[0098] Step 2: In the working mode, the bus capacitor of the converter is charged through a resistor to establish a bus voltage.

[0099] In some embodiments of the present disclosure, step 2 may include at least one step from step 21 to step 23, and the order of step 21 to step 23 may be adjusted.

[0100] Step 21: In the first working mode, the photovoltaic system is used to charge the bus capacitor of the converter through a resistor to establish a bus voltage.

[0101] The above embodiments of the present disclosure give photovoltaics a higher priority. When both photovoltaics and energy storage are connected, the photovoltaic system is used to charge the bus capacitor of the converter through a resistor to establish a bus voltage. This can fully utilize the photovoltaic power generation and better achieve energy saving and energy storage of the energy storage system.

[0102] In some embodiments of the present disclosure, step 21 may include at least one step from step 211 to step 214, and the order of step 211 to step 214 may be adjusted.

[0103] Step 211, determining whether the current photovoltaic voltage is within a predetermined photovoltaic voltage range.

[0104] Step 212: When the current photovoltaic voltage is within the predetermined photovoltaic voltage range, close the Figure 3 The first charging switch K6 shown adopts the photovoltaic system to charge the bus capacitance of the converter through a resistor.

[0105] Figure 3 The schematic diagram of some embodiments of the inverter startup control system of the present disclosure is as follows. The inverter startup control system of the present disclosure comprises a control device in any of the above embodiments of the present disclosure and a photovoltaic system access control circuit.

[0106] In some embodiments of the present disclosure, Figure 3 As shown, the photovoltaic system access control circuit may include a first charging switch K6, a first resistor R1 and a first working switch K1. The first charging switch K6 and the first resistor R1 are connected in series and then connected in parallel with the first working switch K1. The first charging switch K6 is configured to, when closed, allow the photovoltaic system to charge the bus capacitor of the converter through the first resistor R1. The first working switch K1 is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0107] Step 213, detecting whether the bus voltage is established.

[0108] Step 214: When the bus voltage is established, close the first working switch K1, and the converter outputs an inverter voltage.

[0109] In the case of photovoltaic access, the above embodiments of the present disclosure are in the first working mode regardless of whether energy storage is connected. In this mode, the DC can charge the busbar through photovoltaics to establish a DC voltage. The above embodiments of the present disclosure preferentially use the photovoltaic system to charge the busbar capacitor, thereby achieving energy saving.

[0110] The above-mentioned embodiment of the present disclosure outputs an inverter voltage after the bus voltage is established, thereby determining the angle compensation amount and the voltage compensation amount by comparing the inverter voltage with the grid voltage, and compensating the starting angle and voltage of the converter, thereby reducing the starting current impact and achieving stable starting of the converter.

[0111] The above embodiments of the present disclosure use resistors to connect the bus capacitors of the converter in order to reduce the charging current to protect the bus capacitors from damage; at the same time, the peak voltage is reduced to maintain the stability of the bus voltage. After the bus voltage is established, the short-circuit resistor is directly connected to the photovoltaic voltage to provide a large current in order to more effectively utilize the energy output by the photovoltaic system to achieve energy saving.

[0112] Step 22: In the second working mode, the energy storage system is used to charge the bus capacitor of the converter through a resistor to establish a bus voltage.

[0113] The above embodiment of the present disclosure is in the second working mode when the energy storage is connected and the photovoltaic is not connected. The above embodiment of the present disclosure gives priority to using the energy storage system to charge the bus capacitor when the photovoltaic is not connected. DC charging can charge the bus capacitor faster than AC charging, and there is no need for the conversion process of AC to DC in AC charging, thereby achieving energy saving. The energy of the energy storage system in the above embodiment of the present disclosure may be the storage of the previous photovoltaic power generation energy. Therefore, compared with the power grid, the energy storage system is given priority for charging, which can also save the energy of the power grid.

[0114] In some embodiments of the present disclosure, step 22 may include at least one step from step 221 to step 224, and the order of step 221 to step 224 may be adjusted.

[0115] Step 221, determining whether the energy storage charge state is within a predetermined range.

[0116] Step 222: When the energy storage charge state is within a predetermined range, close the Figure 3 The second charging switch K7 shown uses an energy storage system to charge the bus capacitor of the converter through a resistor.

[0117] In some embodiments of the present disclosure, Figure 3The converter startup control system shown may also include: an energy storage system access control circuit, wherein the energy storage system access control circuit includes a second charging switch K7, a second resistor R2 and a second working switch K2, the second charging switch K7 and the second resistor R2 are connected in series and then connected in parallel with the second working switch K2, the second charging switch K7 is configured to, when closed, allow the energy storage system to charge the bus capacitor of the converter through the second resistor R2, and the second working switch K2 is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0118] Step 223, detecting whether the bus voltage is established.

[0119] Step 224, when the bus voltage is established, close the Figure 3 The second working switch K2 shown in the figure, the converter outputs an inverter voltage.

[0120] In the above-mentioned embodiments of the present disclosure, when photovoltaic power is not connected, compared with the AC power supply of the power grid, the energy storage system is preferably used to charge the bus capacitor. DC charging can charge the bus capacitor faster than AC charging, and there is no need for the AC to DC conversion process in AC charging, thereby achieving energy saving.

[0121] The above-mentioned embodiment of the present disclosure outputs an inverter voltage after the bus voltage is established, thereby determining the angle compensation amount and the voltage compensation amount by comparing the inverter voltage with the grid voltage, and compensating the starting angle and voltage of the converter, thereby reducing the starting current impact and achieving stable starting of the converter.

[0122] The above embodiments of the present disclosure use resistors to connect the bus capacitors of the converter in order to reduce the charging current and protect the bus capacitors from being damaged. After the bus voltage is established, the short-circuit resistor is connected directly to the energy storage voltage to provide a large current in order to more effectively utilize the energy output by the energy storage system to achieve energy saving.

[0123] Step 23, in the third working mode, the bus capacitor of the converter is charged by the grid voltage through a resistor to establish a bus voltage.

[0124] The above embodiment of the present disclosure is in the third working mode when neither photovoltaic power generation nor energy storage is connected. In this mode, photovoltaic power generation and energy storage cannot establish a charging voltage for the busbar, and the voltage can only be established by charging the busbar through the AC side.

[0125] The above embodiments of the present disclosure can use different power sources (photovoltaic system, energy storage system and AC power supply) to charge the bus capacitor according to different working modes, thereby improving the adaptability of the system and improving the energy-saving effect.

[0126] In some embodiments of the present disclosure, step 23 may include at least one step from step 231 to step 234, and the order of step 231 to step 234 may be adjusted.

[0127] Step 231, determining whether the AC voltage is within a predetermined voltage range.

[0128] Step 232: When the AC voltage is within the predetermined voltage range, close the Figure 3 The third charging switch K4 shown uses the grid voltage to charge the bus capacitor of the converter through a resistor.

[0129] In the above embodiments of the present disclosure, the access of photovoltaic and energy storage voltages has range requirements, and the AC voltage operation also has range requirements. Therefore, the above embodiments of the present disclosure need to determine the voltage range of photovoltaic, energy storage and AC power supplies.

[0130] Based on the relevant technology, the grid side is first established to solve the technical problems caused by connecting to photovoltaic or energy storage. The above-mentioned embodiment of the present disclosure selects the establishment of bus voltage according to the situation by automatically judging the voltage of photovoltaic, energy storage and grid side.

[0131] In some embodiments of the present disclosure, Figure 3 The converter startup control system shown may also include: a grid access control circuit, wherein the grid access control circuit includes a first rectifier 31, a third charging switch K4, a third resistor R3 and a third working switch K5, the first rectifier is configured to convert the grid AC voltage into a DC voltage, the third charging switch K4 and the third resistor are connected in series and then connected in parallel with the third working switch K5, the third charging switch K4 is configured to, when closed, allow the grid voltage to charge the bus capacitor of the converter through the first rectifier 31 and the third resistor R3, and the third working switch K5 is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0132] Step 233, detecting whether the bus voltage is established.

[0133] Step 234, when the bus voltage is established, close the Figure 3 The third working switch K5 shown is used for the converter to output an inverter voltage.

[0134] The above-mentioned embodiment of the present disclosure outputs an inverter voltage after the bus voltage is established, thereby determining the angle compensation amount and the voltage compensation amount by comparing the inverter voltage with the grid voltage, and compensating the starting angle and voltage of the converter, thereby reducing the starting current impact and achieving stable starting of the converter.

[0135] The above embodiment of the present disclosure mainly charges the intermediate capacitor through K4 and the resistor. After charging is completed, K5 is closed to bypass the resistor. After K5 is closed, there is no resistor. Directly energizing the bus capacitor will cause problems and damage the bus capacitor. K5 is a bypass switch. After charging is completed, the resistor needs to be bypassed. If it is not bypassed, the subsequent large current will flow through the circuit and the loss will be relatively large.

[0136] The above embodiments of the present disclosure use resistors to connect the bus capacitors of the converter in order to reduce the charging current and protect the bus capacitors from being damaged. After the bus voltage is established, the short-circuit resistor is connected directly to the grid voltage through the rectifier to provide a large current in order to more effectively utilize the energy output by the grid to achieve energy saving.

[0137] Step 3: Determine the angle compensation amount and voltage compensation amount of the working mode according to the value of the bus voltage, the amplitude, phase and frequency of the grid voltage.

[0138] In some embodiments of the present disclosure, step 3 may include at least one step from step 31 to step 35, and the order of steps 31 to step 35 may be adjusted.

[0139] Step 31, obtaining the bus voltage; obtaining the amplitude, phase and frequency of the grid voltage.

[0140] Step 32: Using the amplitude, phase and frequency of the grid voltage as the target amplitude, target phase and target frequency of the inverter voltage.

[0141] Step 33: Generate the inverter voltage according to the bus voltage, and the target amplitude, target phase and target frequency of the inverter voltage.

[0142] In some embodiments of the present disclosure, step 33 may include at least one of step 331 and step 332, and the order of step 331 and step 332 may be adjusted.

[0143] Step 331, determining an inverter modulation wave required to generate the inverter voltage according to the bus voltage, the target amplitude, the target phase and the target frequency of the inverter voltage.

[0144] In some embodiments of the present disclosure, step 331 may include: determining the inverter modulation wave required to generate an inverter voltage synchronized with the amplitude, phase and frequency of the grid voltage based on the bus voltage and the amplitude, phase and frequency of the grid voltage.

[0145] In some embodiments of the present disclosure, step 331 may include: determining the inverter modulation wave required to generate the inverter voltage according to formula (1) and formula (2).

[0146] Vinv=M sin(wt+θ)(1)

[0147] w=2πf(2)

[0148] In formula (1) and formula (2), Vinv is the inverter modulation wave; M is the target amplitude of the inverter modulation wave; f is the frequency of the grid voltage; θ is the angle that is consistent with the grid voltage phase;

[0149] In some embodiments of the present disclosure, according to formula (1) and formula (2), when the DC voltage and the grid voltage are known, the target amplitude M of the modulation wave can be determined, so that the inverter modulation wave Vinv obtained, after high-frequency PWM modulation driving and controlling the inverter, the inverter voltage obtained is consistent with the grid voltage in terms of magnitude, frequency, and phase. Step 332, generating the inverter voltage according to the bus voltage and the inverter modulation wave.

[0150] The above-mentioned embodiments of the present disclosure can determine the inverter modulation wave required to generate the inverter voltage through the bus voltage, the target amplitude, target phase and target frequency of the inverter voltage, so as to modulate and generate the inverter voltage. Therefore, the above-mentioned embodiments of the present disclosure can conveniently generate the inverter voltage, so that the angle compensation amount and the voltage compensation amount can be accurately determined according to the actual amplitude and actual phase of the inverter voltage, and the amplitude and phase of the grid voltage. Therefore, the above-mentioned embodiments of the present disclosure can further reduce the starting peak, reduce the starting current impact, and improve the stability of the converter starting.

[0151] Step 34, obtaining the actual amplitude and actual phase of the inverter voltage.

[0152] Step 35, determining an angle compensation amount and a voltage compensation amount according to the actual amplitude and actual phase of the inverter voltage and the amplitude and phase of the grid voltage.

[0153] In some embodiments of the present disclosure, step 35 may include: generating a sine wave with the same frequency as the grid frequency through a DC inverter unit, filtering through a reactor, collecting the voltage on the right side (point B) of the AC switch K3 and comparing it with the grid voltage on the left side (point A) of K3.

[0154] In some embodiments of the present disclosure, Figure 3 As shown, the sine wave generated on the right side of K3 (point B) is the sine wave generated by detecting the voltage angle on the left side of K3. The generated sine wave will have a certain phase deviation from the sine wave of the power grid due to program processing calculations and other reasons.

[0155] In some embodiments of the present disclosure, the deviation is within the angle interval [0, 2*pi]. The angle deviation is obtained by calculating the zero-crossing points of the two waveforms to compensate for the delay from program sampling to output of the sine wave after filtering.

[0156] In some embodiments of the present disclosure, step 35 may include: collecting Figure 3 The voltages at points A and B are shown, and the program calculates the angle and angular deviation.

[0157] In some embodiments of the present disclosure, step 35 may include: if you want to generate a sine wave like the power grid on the right side of K3, you need to collect the amplitude, phase and frequency of the power grid. There will be a deviation between the production of the sine wave and the sampling data, which is the compensation amount.

[0158] The above embodiment of the present disclosure uses the amplitude, phase and frequency of the grid voltage as the target amplitude, target phase and target frequency of the inverter voltage, and can generate the inverter voltage according to the bus voltage, and the target amplitude, target phase and target frequency of the inverter voltage, thereby determining the angle compensation amount and the voltage compensation amount according to the actual amplitude and actual phase of the inverter voltage, and the amplitude and phase of the grid voltage. Therefore, the above embodiment of the present disclosure can accurately determine the angle compensation amount and the voltage compensation amount, thereby further reducing the starting peak, reducing the starting current impact, and improving the stability of the converter starting.

[0159] Step 4: Compensate the current angle and current voltage of the converter at startup according to the angle compensation amount and voltage compensation amount of the working mode, and start the converter according to the compensated angle and compensated voltage.

[0160] The above-mentioned embodiments of the present disclosure can automatically select a solution to establish the bus voltage according to various situations with or without photovoltaics and energy storage, thereby realizing the correction of the voltage amplitude and angle according to the mode of the converter.

[0161] The above embodiments of the present disclosure can automatically correct the voltage amplitude and angle according to the various modes of photovoltaic and energy storage to reduce the starting current impact. This can reduce the starting peak to achieve stable starting of the converter. The above embodiments of the present disclosure no longer require manual correction of the grid-side voltage frequency.

[0162] In some embodiments of the present disclosure, step 4 may include at least one step from step 41 to step 44, and the order of step 41 to step 44 may be adjusted.

[0163] Step 41 , when the angle compensation amount is zero and the voltage compensation amount is zero, starting the converter according to the current angle and current voltage of the converter.

[0164] Step 42, when the angle compensation amount is not zero and the voltage compensation amount is not zero, the current angle of the converter startup is compensated according to the angle compensation amount of the working mode, and the current voltage of the converter startup is compensated according to the voltage compensation amount of the working mode, and the converter is started according to the compensated angle and the compensated voltage.

[0165] In the above embodiment of the present disclosure, if the angle compensation amount and the voltage compensation amount are both zero, the angle and the voltage both use the current values; if the angle compensation amount and the voltage compensation amount are not zero, both the angle and the voltage are compensated.

[0166] The above-mentioned embodiments of the present disclosure realize the comparison and compensation of angles and phases for the first time, thereby greatly reducing the starting peak, reducing the starting current impact, and improving the starting stability of the converter.

[0167] Step 43, when the angle compensation amount is zero and the voltage compensation amount is not zero, the current voltage at the start of the converter is compensated according to the voltage compensation amount of the working mode, and the converter is started according to the current angle at the start of the converter and the compensated voltage.

[0168] Step 44, when the angle compensation amount is not zero and the voltage compensation amount is zero, the current angle of the converter startup is compensated according to the angle compensation amount of the working mode, and the converter is started according to the current voltage at the converter startup and the compensated angle.

[0169] In the above embodiment of the present disclosure, if any one of the angle compensation amount and the voltage compensation amount is not zero, the item is compensated. The above embodiment of the present disclosure can realize compensation for any one of the angle and the voltage, thereby further reducing the starting peak, reducing the starting current impact, and improving the stability of the converter startup.

[0170] Figure 4 Schematic diagrams of other embodiments of the converter startup control method disclosed in the present invention. Figure 4 The embodiment can be executed by the inverter startup control device of the present disclosure, the inverter startup control system of the present disclosure, the inverter system of the present disclosure, or the air conditioning system of the present disclosure. Figure 4 As shown, Figure 4 The method of the embodiment may include at least one of steps 400 to 429 , and the order of steps 400 to 429 may be adjusted.

[0171] Step 400: The system is powered on and connected to the power grid.

[0172] Step 401 , detecting whether the photovoltaic system is connected. If the photovoltaic system is connected to the inverter, step 402 is executed; otherwise, if the photovoltaic system is not connected to the inverter, step 411 is executed.

[0173] Step 402: When the photovoltaic system is connected to the inverter, determine that the working mode of the inverter is the first working mode.

[0174] Step 403, determine whether the current photovoltaic voltage is within the predetermined photovoltaic voltage range. If the photovoltaic voltage is within the predetermined photovoltaic voltage range, execute step 404; otherwise, if the photovoltaic voltage is not within the predetermined photovoltaic voltage range, continue to execute step 403 within a predetermined time, that is, within the predetermined time, continue to determine whether the current photovoltaic voltage is within the predetermined photovoltaic voltage range; if within the predetermined time, it is still determined that the current photovoltaic voltage is still not within the predetermined photovoltaic voltage range, execute step 411.

[0175] In some embodiments of the present disclosure, the predetermined photovoltaic voltage range may be a predetermined photovoltaic system startup voltage range.

[0176] In some embodiments of the present disclosure, the predetermined photovoltaic voltage range may be a range from a minimum value of MPPT (Maximum Power Point Tracking) to a maximum value of MPPT, that is, [mppt_min, mppt_max].

[0177] Step 404: When the current photovoltaic voltage is within the predetermined photovoltaic voltage range, close the Figure 3 The first charging switch K6 shown uses the photovoltaic system to charge the bus capacitor of the converter through a resistor and detects whether the bus voltage is established. If the bus voltage is established, step 406 is executed; otherwise, if the bus voltage is not established, step 405 is executed.

[0178] Step 405, determine the charging fault and clear the fault. Then execute step 402.

[0179] Step 406: Determine that charging is complete, close the Figure 3 The first working switch K1 shown outputs an inverter voltage.

[0180] Step 407, determine whether there is a deviation between the actual amplitude and actual phase of the inverter voltage, and the amplitude and phase of the grid voltage. If there is no deviation between the actual amplitude of the inverter voltage and the amplitude of the grid voltage, and there is no deviation between the actual phase of the inverter voltage and the phase of the grid voltage, execute step 410; if there is a deviation between at least one of the actual amplitude of the inverter voltage and the amplitude of the grid voltage, and the actual phase of the inverter voltage and the grid voltage, execute step 408.

[0181] Step 408, calculating the deviation (compensation) of voltage and phase.

[0182] In some embodiments of the present disclosure, step 408 may include: determining an angle compensation amount and a voltage compensation amount according to an actual amplitude and an actual phase of the inverter voltage, and an amplitude and a phase of the grid voltage.

[0183] Step 409, start the machine according to the value after adding the compensation amount.

[0184] In some embodiments of the present disclosure, step 409 may include: when the angle compensation amount is not zero and the voltage compensation amount is not zero, according to the angle compensation amount of the working mode, the current angle of the converter startup is compensated, according to the voltage compensation amount of the working mode, the current voltage of the converter startup is compensated, and the converter is started according to the compensated angle and the compensated voltage; when the angle compensation amount is zero and the voltage compensation amount is not zero, according to the voltage compensation amount of the working mode, the current voltage of the converter startup is compensated, and the converter is started according to the current angle of the converter startup and the compensated voltage; when the angle compensation amount is not zero and the voltage compensation amount is zero, according to the angle compensation amount of the working mode, the current angle of the converter startup is compensated, and the converter is started according to the current voltage of the converter startup and the compensated angle.

[0185] Step 410, turn on the device at the current angle.

[0186] In some embodiments of the present disclosure, step 410 may include: when the angle compensation amount is zero and the voltage compensation amount is zero, starting the converter according to the current angle and current voltage of the converter.

[0187] Step 411 , detecting whether the energy storage system is connected. If the energy storage system is connected to the converter, execute step 412 ; otherwise, if the energy storage system is not connected to the converter, execute step 421 .

[0188] Step 412: When the photovoltaic system is not connected to the inverter and the energy storage system is connected to the inverter, determine that the operating mode of the inverter is the second operating mode.

[0189] Step 413, determine whether the energy storage state of charge (SOC) is within a predetermined range. If the energy storage SOC is within the predetermined range, execute step 414; otherwise, if the energy storage SOC is not within the predetermined range, continue to execute step 413 within a predetermined time, that is, within the predetermined time, continue to determine whether the energy storage SOC is within the predetermined range; if within the predetermined time, it is still determined that the energy storage SOC is still not within the predetermined range, execute step 421.

[0190] In some embodiments of the present disclosure, the predetermined interval range may be an interval range of [20%, 100%].

[0191] Step 414: When the energy storage charge state is within a predetermined range, close the Figure 3 The second charging switch K7 shown uses the energy storage system to charge the bus capacitor of the converter through a resistor and detects whether the bus voltage is established. If the bus voltage is established, step 416 is executed; otherwise, if the bus voltage is not established, step 415 is executed.

[0192] Step 415, determine the charging fault and clear the fault. Then execute step 402.

[0193] Step 416, when the bus voltage is established, close the Figure 3 The second working switch K2 shown in the figure, the converter outputs an inverter voltage.

[0194] Step 417, determine whether there is a deviation between the actual amplitude and actual phase of the inverter voltage, and the amplitude and phase of the grid voltage. If there is no deviation between the actual amplitude of the inverter voltage and the amplitude of the grid voltage, and there is no deviation between the actual phase of the inverter voltage and the phase of the grid voltage, execute step 420; if there is a deviation between at least one of the actual amplitude of the inverter voltage and the amplitude of the grid voltage, and the actual phase of the inverter voltage and the grid voltage, execute step 418.

[0195] Step 418, calculating the deviation (compensation) of voltage and phase.

[0196] In some embodiments of the present disclosure, step 418 may include: determining an angle compensation amount and a voltage compensation amount according to an actual amplitude and an actual phase of the inverter voltage, and an amplitude and a phase of the grid voltage.

[0197] Step 419, start the machine according to the value after adding the compensation amount.

[0198] In some embodiments of the present disclosure, step 419 may include: when the angle compensation amount is not zero and the voltage compensation amount is not zero, according to the angle compensation amount of the working mode, the current angle of the converter startup is compensated, according to the voltage compensation amount of the working mode, the current voltage of the converter startup is compensated, and the converter is started according to the compensated angle and the compensated voltage; when the angle compensation amount is zero and the voltage compensation amount is not zero, according to the voltage compensation amount of the working mode, the current voltage of the converter startup is compensated, and the converter is started according to the current angle of the converter startup and the compensated voltage; when the angle compensation amount is not zero and the voltage compensation amount is zero, according to the angle compensation amount of the working mode, the current angle of the converter startup is compensated, and the converter is started according to the current voltage of the converter startup and the compensated angle.

[0199] Step 420, turn on the device at the current angle.

[0200] In some embodiments of the present disclosure, step 420 may include: when the angle compensation amount is zero and the voltage compensation amount is zero, starting the converter according to the current angle and current voltage of the converter.

[0201] Step 421, when the photovoltaic system is not connected to the converter and the energy storage system is not connected to the converter, determine that the working mode of the converter is the third working mode, and charge the busbar to establish voltage through the AC side.

[0202] Step 422, determine whether the AC voltage is within the predetermined voltage range. If the AC voltage is within the predetermined voltage range, execute step 423; otherwise, if the AC voltage is not within the predetermined voltage range, continue to execute step 422 within the predetermined time, that is, within the predetermined time, continue to determine whether the AC voltage is within the predetermined voltage range; if within the predetermined time, it is continuously determined that the AC voltage is still not within the predetermined voltage range, then report an error to the outside, clear the fault, and continue to execute step 422.

[0203] In some embodiments of the present disclosure, the predetermined voltage range may be between [90%, 110%].

[0204] Step 423: When the AC voltage is within the predetermined voltage range, close the Figure 3 The third charging switch K4 shown uses the grid voltage to charge the bus capacitor of the converter through a resistor and detects whether the bus voltage is established. If the bus voltage is established, step 425 is executed; otherwise, if the bus voltage is not established, step 424 is executed.

[0205] Step 424, determine the charging fault and clear the fault. Then execute step 421.

[0206] Step 425, determine that charging is complete, close the Figure 3 The third working switch K5 shown outputs an inverter voltage.

[0207] Step 426, determine whether there is a deviation between the actual amplitude and actual phase of the inverter voltage, and the amplitude and phase of the grid voltage. If there is no deviation between the actual amplitude of the inverter voltage and the amplitude of the grid voltage, and there is no deviation between the actual phase of the inverter voltage and the phase of the grid voltage, execute step 429; if there is a deviation between at least one of the actual amplitude of the inverter voltage and the amplitude of the grid voltage, and the actual phase of the inverter voltage and the grid voltage, execute step 427.

[0208] Step 427, calculating the deviation (compensation) of voltage and phase.

[0209] In some embodiments of the present disclosure, step 427 may include: determining an angle compensation amount and a voltage compensation amount according to an actual amplitude and an actual phase of the inverter voltage, and an amplitude and a phase of the grid voltage.

[0210] Step 428, start the machine according to the value after adding the compensation amount.

[0211] In some embodiments of the present disclosure, step 428 may include: when the angle compensation amount is not zero and the voltage compensation amount is not zero, according to the angle compensation amount of the working mode, the current angle of the converter startup is compensated, according to the voltage compensation amount of the working mode, the current voltage of the converter startup is compensated, and the converter is started according to the compensated angle and the compensated voltage; when the angle compensation amount is zero and the voltage compensation amount is not zero, according to the voltage compensation amount of the working mode, the current voltage of the converter startup is compensated, and the converter is started according to the current angle and the compensated voltage of the converter startup; when the angle compensation amount is not zero and the voltage compensation amount is zero, according to the angle compensation amount of the working mode, the current angle of the converter startup is compensated, and the converter is started according to the current voltage and the compensated angle of the converter startup.

[0212] Step 429, turn on the device at the current angle.

[0213] In some embodiments of the present disclosure, step 429 may include: when the angle compensation amount is zero and the voltage compensation amount is zero, starting the converter according to the current angle and current voltage of the converter.

[0214] The above-mentioned embodiments of the present disclosure propose a compensation method according to various modes to reduce the starting current impact.

[0215] The above-mentioned embodiments of the present disclosure no longer require manual correction of the grid-side voltage frequency.

[0216] The above-mentioned embodiments of the present disclosure can provide a suitable correction method regardless of whether photovoltaic power is connected or not.

[0217] The above-mentioned embodiment of the present disclosure proposes a startup control method for an inverter, which automatically selects a scheme to establish a bus voltage for various situations with or without photovoltaics and energy storage. After the bus is established, the voltage can replace the relevant technical scheme to automatically correct the grid voltage and frequency. According to the mode of the inverter, the voltage amplitude, angle and phase are corrected, thereby reducing the startup peak.

[0218] Figure 5 Schematic diagram of the structure of some embodiments of the control device disclosed in the present invention. Figure 5As shown, the control device of the present disclosure may include a working mode determination module 51 , a bus voltage establishment module 52 , a compensation amount determination module 53 and a start control module 54 .

[0219] The working mode determination module 51 is configured to determine the working mode of the converter according to whether at least one of the photovoltaic system and the energy storage system is connected to the converter.

[0220] In some embodiments of the present disclosure, the working mode determination module 51 can be configured to perform at least one of the following operations: when the photovoltaic system is connected to the inverter, determine that the working mode of the inverter is the first working mode; when the photovoltaic system is not connected to the inverter and the energy storage system is connected to the inverter, determine that the working mode of the inverter is the second working mode; when the photovoltaic system is not connected to the inverter and the energy storage system is not connected to the inverter, determine that the working mode of the inverter is the third working mode.

[0221] The bus voltage establishing module 52 is configured to charge the bus capacitor of the converter through a resistor to establish the bus voltage in the working mode.

[0222] In some embodiments of the present disclosure, the bus voltage establishing module 52 can be configured to perform at least one of the following operations: in the first working mode, the photovoltaic system is used to charge the bus capacitor of the converter through a resistor to establish the bus voltage; in the second working mode, the energy storage system is used to charge the bus capacitor of the converter through a resistor to establish the bus voltage; in the third working mode, the grid voltage is used to charge the bus capacitor of the converter through a resistor to establish the bus voltage.

[0223] In some embodiments of the present disclosure, the bus voltage establishing module 52 can be configured to determine whether the current photovoltaic voltage is within a predetermined photovoltaic voltage range when the photovoltaic system is used to charge the bus capacitor of the inverter through a resistor to establish the bus voltage; when the current photovoltaic voltage is within the predetermined photovoltaic voltage range, close the first charging switch and use the photovoltaic system to charge the bus capacitor of the inverter through a resistor; detect whether the bus voltage is established; when the bus voltage is established, close the first working switch and the inverter outputs an inverter voltage.

[0224] In some embodiments of the present disclosure, the bus voltage establishing module 52 can be configured to determine whether the energy storage charge state is within a predetermined range when the energy storage charge state is within the predetermined range by using the energy storage system to charge the bus capacitor of the converter through a resistor to establish the bus voltage; when the energy storage charge state is within the predetermined range, close the second charging switch and use the energy storage system to charge the bus capacitor of the converter through a resistor; detect whether the bus voltage is established; when the bus voltage is established, close the second working switch and the converter outputs an inverter voltage.

[0225] In some embodiments of the present disclosure, the bus voltage establishing module 52 can be configured to determine whether the AC voltage is within a predetermined voltage range when the grid voltage is used to charge the bus capacitor of the converter through a resistor to establish the bus voltage; when the AC voltage is within the predetermined voltage range, close the third charging switch and use the grid voltage to charge the bus capacitor of the converter through a resistor; detect whether the bus voltage is established; when the bus voltage is established, close the third working switch and the converter outputs an inverter voltage.

[0226] The compensation amount determination module 53 is configured to determine the angle compensation amount and the voltage compensation amount of the working mode according to the value of the bus voltage, the amplitude, phase and frequency of the grid voltage.

[0227] In some embodiments of the present disclosure, the compensation amount determination module 53 can be configured to obtain the amplitude, phase and frequency of the grid voltage; use the amplitude, phase and frequency of the grid voltage as the target amplitude, target phase and target frequency of the inverter voltage; generate the inverter voltage according to the bus voltage, and the target amplitude, target phase and target frequency of the inverter voltage; obtain the actual amplitude and actual phase of the inverter voltage; determine the angle compensation amount and the voltage compensation amount according to the actual amplitude and actual phase of the inverter voltage, and the amplitude and phase of the grid voltage.

[0228] In some embodiments of the present disclosure, the compensation amount determination module 53 can be configured to determine the inverter modulation wave required to generate the inverter voltage based on the bus voltage, the target amplitude, target phase and target frequency of the inverter voltage when generating the inverter voltage based on the bus voltage, the target amplitude, target phase and target frequency of the inverter voltage; and generate the inverter voltage based on the bus voltage and the inverter modulation wave.

[0229] The start control module 54 is configured to compensate the current angle and current voltage of the converter at start-up according to the angle compensation amount and voltage compensation amount of the working mode, and start the converter according to the compensated angle and compensated voltage.

[0230] In some embodiments of the present disclosure, the starting control module 54 can be configured to start the converter according to the current angle and current voltage of the converter when the angle compensation amount is zero and the voltage compensation amount is zero; and to compensate for the current angle of the converter when the angle compensation amount is not zero and the voltage compensation amount is not zero according to the angle compensation amount of the working mode, and compensate for the current voltage of the converter when the converter is started according to the voltage compensation amount of the working mode, and start the converter according to the compensated angle and the compensated voltage.

[0231] In some embodiments of the present disclosure, the starting control module 54 can be configured to compensate the current voltage at the start-up of the converter according to the voltage compensation amount of the operating mode when the angle compensation amount is zero and the voltage compensation amount is not zero, and to start the converter according to the current angle at the start-up of the converter and the compensated voltage; and to compensate the current angle at the start-up of the converter according to the angle compensation amount of the operating mode when the angle compensation amount is not zero and the voltage compensation amount is zero, and to start the converter according to the current voltage at the start-up of the converter and the compensated angle.

[0232] Figure 6 Schematic diagram of the structure of some other embodiments of the control device disclosed in the present invention. Figure 6 As shown, the control device of the present disclosure may include a memory 61 and a processor 62 .

[0233] The memory 61 is used to store instructions. The processor 62 is coupled to the memory 61 . The processor 62 is configured to execute the converter startup control method involved in the above embodiment based on the instructions stored in the memory.

[0234] like Figure 6 As shown, the control device further includes a communication interface 63 for information exchange with other devices. At the same time, the control device further includes a bus 64, through which the processor 62, the communication interface 63, and the memory 61 communicate with each other.

[0235] The memory 61 may include a high-speed RAM memory, and may also include a non-volatile memory, such as at least one disk memory. The memory 61 may also be a memory array. The memory 61 may also be divided into blocks, and the blocks may be combined into virtual volumes according to certain rules.

[0236] In addition, the processor 62 may be a central processing unit (CPU), or may be an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present disclosure.

[0237] Figure 7 Schematic diagrams of other embodiments of the converter startup control system disclosed in the present invention. Figure 7 As shown, the inverter startup control system disclosed in the present invention includes a control device 71 and a photovoltaic system access control circuit 72 .

[0238] The control device 71 may be any of the above embodiments of the present disclosure (for example Figure 5 or Figure 6 ) in the control device.

[0239] In some embodiments of the present disclosure, Figure 3 As shown, Figure 7The photovoltaic system access control circuit of the embodiment may include a first charging switch K6, a first resistor R1 and a first working switch K1. The first charging switch K6 and the first resistor R1 are connected in series and then connected in parallel with the first working switch K1. The first charging switch K6 is configured to, when closed, allow the photovoltaic system to charge the bus capacitor of the converter through the first resistor R1. The first working switch K1 is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0240] In some embodiments of the present disclosure, Figure 7 As shown, the converter startup control system may further include an energy storage system access control circuit 73 .

[0241] In some embodiments of the present disclosure, Figure 3 As shown, Figure 7 The energy storage system access control circuit 73 of the embodiment may include a second charging switch K7, a second resistor R2 and a second working switch K2. The second charging switch K7 and the second resistor R2 are connected in series and then connected in parallel with the second working switch K2. The second charging switch K7 is configured to, when closed, allow the energy storage system to charge the bus capacitor of the converter through the second resistor R2. The second working switch K2 is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0242] In some embodiments of the present disclosure, Figure 7 As shown, the converter startup control system may further include a grid access control circuit 74 .

[0243] In some embodiments of the present disclosure, Figure 3 As shown, Figure 7 The grid access control circuit of the embodiment may include a first rectifier 31, a third charging switch K4, a third resistor R3 and a third working switch K5. The first rectifier is configured to convert the grid AC voltage into a DC voltage. The third charging switch K4 and the third resistor are connected in series and in parallel with the third working switch K5. The third charging switch K4 is configured to, when closed, allow the grid voltage to charge the bus capacitor of the converter through the first rectifier 31 and the third resistor R3. The third working switch K5 is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

[0244] The above-mentioned embodiments of the present disclosure are equivalent to adding a charging control unit to each power supply, so as to realize automatic charging and detection of logic.

[0245] In some embodiments of the present disclosure, Figure 7 As shown, the converter startup control system may further include a first acquisition module 75 , a second acquisition module 76 and a third acquisition module 77 .

[0246] The first acquisition module 75 is configured to acquire the bus voltage and send the acquired bus voltage to the control device 71 .

[0247] The second acquisition module 76 is configured to acquire the amplitude, phase and frequency of the grid voltage, and send the acquired amplitude, phase and frequency of the grid voltage to the control device 71 .

[0248] The third acquisition module 77 is configured to acquire the actual amplitude, actual phase and actual frequency of the inverter voltage, and send the acquired actual amplitude, actual phase and actual frequency of the inverter voltage to the control device 71 .

[0249] In some embodiments of the present disclosure, Figure 3 and Figure 7 As shown, the converter startup control system may further include an AC switch K3.

[0250] In some embodiments of the present disclosure, Figure 3 and Figure 7 As shown, the AC switch K3 is arranged between the grid and the converter; the second acquisition module 76 is configured to collect the amplitude, phase and frequency of the grid voltage at point A between the grid and the AC switch K3; the third acquisition module 77 is configured to collect the actual amplitude, actual phase and actual frequency of the inverter voltage at point B between the AC switch K3 and the converter.

[0251] In some embodiments of the present disclosure, Figure 3 As shown, the function of the capacitor and inductor between point B and the converter is to perform LC filtering to filter out the harmonics of the current. The waveform on the right side of the inductor contains large harmonics and needs to be filtered by a reactor. The voltage after LC filtering is compared with the grid voltage.

[0252] The above-mentioned embodiments of the present disclosure propose a unified bus establishment method and a grid voltage and frequency compensation system for converter application systems in different situations.

[0253] The above-mentioned embodiments of the present disclosure are equivalent to adding a charging control unit to each power supply, so as to realize automatic charging and detection of the converter.

[0254] The above-mentioned embodiment of the present disclosure first determines the working mode of the converter to determine the working mode of the converter. After determining the working mode, the bus capacitor is charged through a resistor according to the working mode to establish a standby bus voltage. After the bus charging is completed, the DC voltage established by the DC bus is used to set the voltage and frequency of the AC acquisition to generate an off-grid sine wave output to the right side of K3. K3 is not closed first, and the angle of the sine wave generated by K3 is compared with the angle of the grid sine wave on the left side of K3 to calculate the angle compensation and voltage compensation. After obtaining the angle compensation, the starting angle of the converter is added with this compensation and calculated according to the compensated angle. After obtaining the voltage compensation, the starting voltage of the converter is added with this compensation and calculated according to the compensated voltage. By adaptively judging the charging of different modes and compensating the angle, the peak suppression of the converter system at startup is achieved.

[0255] According to another aspect of the present disclosure, Figure 3 As shown, a converter system is provided, including a photovoltaic system, an energy storage system, a converter, and a converter startup control system as described in any of the above embodiments.

[0256] In some embodiments of the present disclosure, the converter system may be an energy storage converter system.

[0257] According to another aspect of the present disclosure, Figure 3 As shown, an air conditioning system is provided, comprising an air conditioner and an inverter system as described in any of the above embodiments.

[0258] In some embodiments of the present disclosure, the air-conditioning system may be a photovoltaic air-conditioning system.

[0259] In some embodiments of the present disclosure, the air-conditioning system may be a solar storage air-conditioning system.

[0260] In some embodiments of the present disclosure, Figure 3 As shown, the air conditioner may include an air conditioner variable frequency motor.

[0261] The inverter startup control method, device and system of the above embodiments of the present disclosure can be applied to a single inverter system or to an air conditioning system.

[0262] According to another aspect of the present disclosure, a computer program product is provided, including a computer program, wherein when the computer program is executed by a processor, the converter startup control method as described in any of the above embodiments is implemented.

[0263] According to another aspect of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer instructions, and when the instructions are executed by a processor, the converter startup control method as described in any of the above embodiments is implemented.

[0264] The computer-readable storage medium of the present disclosure may be implemented as a non-transitory computer-readable storage medium.

[0265] Those skilled in the art will appreciate that the embodiments of the present disclosure may be provided as methods, devices, or computer program products. Therefore, the present disclosure may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present disclosure may take the form of a computer program product implemented on one or more computer-usable non-transient storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0266] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems) and computer program products according to embodiments of the present disclosure. It should be understood that each process and / or block in the flowchart and / or block diagram and the combination of processes and / or blocks in the flowchart and / or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0267] These computer program instructions may also be stored in a computer readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture including an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0268] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0269] The control device, working mode determination module, bus voltage establishment module, compensation amount determination module and startup control module described above can be implemented as a general-purpose processor, a programmable logic controller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component or any appropriate combination thereof for performing the functions described in the present disclosure.

[0270] Those skilled in the art will appreciate that all or part of the steps of the above-described embodiment method of the present disclosure may be accomplished by hardware, and the hardware may be implemented as a general-purpose processor, a programmable logic controller, a digital signal processor, an application-specific integrated circuit, a field programmable gate array or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any appropriate combination thereof for executing the method described in the present disclosure.

[0271] So far, the present disclosure has been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0272] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware, or may be accomplished by instructing the relevant hardware through a program, and the program may be stored in a non-transitory computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.

[0273] The description of the present disclosure is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present disclosure to the disclosed form. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present disclosure, and to enable those of ordinary skill in the art to understand the present disclosure and thereby design various embodiments with various modifications suitable for specific uses.

Claims

1. A converter startup control method, comprising: determining a working mode of the converter according to whether at least one of the photovoltaic system and the energy storage system is connected to the converter; In the working mode, the bus capacitor of the converter is charged through the resistor to establish the bus voltage; Determining the angle compensation amount and the voltage compensation amount of the working mode according to the value of the bus voltage, the amplitude, phase and frequency of the grid voltage; According to the angle compensation amount and the voltage compensation amount of the working mode, the current angle and the current voltage of the converter at startup are compensated, and the converter is started according to the compensated angle and the compensated voltage.

2. The converter startup control method according to claim 1, wherein: Determining the working mode of the converter according to whether at least one of the photovoltaic system and the energy storage system is connected to the converter comprises at least one of the following steps: When the photovoltaic system is connected to the converter, determining that the working mode of the converter is the first working mode; When the photovoltaic system is not connected to the converter and the energy storage system is connected to the converter, determining that the working mode of the converter is the second working mode; When the photovoltaic system is not connected to the converter and the energy storage system is not connected to the converter, the operating mode of the converter is determined to be the third operating mode.

3. The converter startup control method according to claim 2, wherein: In the working mode, charging the bus capacitor of the converter through the resistor to establish the bus voltage includes at least one of the following steps: In the first working mode, the photovoltaic system is used to charge the bus capacitor of the converter through a resistor to establish a bus voltage; In the second working mode, the energy storage system is used to charge the bus capacitor of the converter through a resistor to establish a bus voltage; In the third working mode, the grid voltage is used to charge the bus capacitor of the converter through a resistor to establish the bus voltage.

4. The converter startup control method according to claim 3, wherein: The method of using the photovoltaic system to charge the bus capacitor of the converter through a resistor to establish the bus voltage includes: Determine whether the current photovoltaic voltage is within a predetermined photovoltaic voltage range; When the current photovoltaic voltage is within the predetermined photovoltaic voltage range, the first charging switch is closed to charge the bus capacitor of the converter through the resistance of the photovoltaic system; Detect whether the bus voltage is established; When the bus voltage is established, the first working switch is closed and the converter outputs an inverter voltage.

5. The converter startup control method according to claim 3, wherein: The method of using the energy storage system to charge the bus capacitor of the converter through a resistor to establish the bus voltage includes: Determine whether the energy storage charge state is within a predetermined range; When the energy storage charge state is within a predetermined range, the second charging switch is closed, and the bus capacitor of the converter is charged by the energy storage system through a resistor; Detect whether the bus voltage is established; When the bus voltage is established, the second working switch is closed and the converter outputs an inverter voltage.

6. The converter startup control method according to claim 3, wherein: The method of using the grid voltage to charge the bus capacitor of the converter through a resistor to establish the bus voltage includes: determining whether the AC voltage is within a predetermined voltage range; When the AC voltage is within a predetermined voltage range, the third charging switch is closed to charge the bus capacitor of the converter via a resistor using the grid voltage; Detect whether the bus voltage is established; When the bus voltage is established, the third working switch is closed and the converter outputs an inverter voltage.

7. The converter startup control method according to any one of claims 1 to 6, wherein: The compensating the current angle and current voltage of the converter at startup according to the angle compensation amount and the voltage compensation amount of the working mode, and starting the converter according to the compensated angle and the compensated voltage comprises: When the angle compensation amount is zero and the voltage compensation amount is zero, starting the converter according to the current angle and current voltage of the converter; When the angle compensation amount is not zero and the voltage compensation amount is not zero, the current angle of the converter startup is compensated according to the angle compensation amount of the working mode, and the current voltage of the converter startup is compensated according to the voltage compensation amount of the working mode, and the converter is started according to the compensated angle and the compensated voltage.

8. The converter startup control method according to any one of claims 1 to 6, wherein: The compensating the current angle and current voltage of the converter at startup according to the angle compensation amount and the voltage compensation amount of the working mode, and starting the converter according to the compensated angle and the compensated voltage comprises: When the angle compensation amount is zero and the voltage compensation amount is not zero, the current voltage at the start of the converter is compensated according to the voltage compensation amount of the working mode, and the converter is started according to the current angle at the start of the converter and the compensated voltage; When the angle compensation amount is not zero and the voltage compensation amount is zero, the current angle of the converter startup is compensated according to the angle compensation amount of the working mode, and the converter is started according to the current voltage at the converter startup and the compensated angle.

9. The converter startup control method according to any one of claims 1 to 6, wherein: Determining the angle compensation amount and the voltage compensation amount of the working mode according to the value of the bus voltage, the amplitude, phase and frequency of the grid voltage includes: Obtain the amplitude, phase and frequency of the grid voltage; The amplitude, phase and frequency of the grid voltage are used as the target amplitude, target phase and target frequency of the inverter voltage; generating the inverter voltage according to the bus voltage, and the target amplitude, target phase and target frequency of the inverter voltage; Obtaining the actual amplitude and actual phase of the inverter voltage; An angle compensation amount and a voltage compensation amount are determined according to the actual amplitude and actual phase of the inverter voltage and the amplitude and phase of the grid voltage.

10. The converter startup control method according to claim 9, wherein: Generating the inverter voltage according to the bus voltage, and the target amplitude, target phase, and target frequency of the inverter voltage comprises: Determining an inverter modulation wave required to generate the inverter voltage according to the bus voltage, the target amplitude, the target phase and the target frequency of the inverter voltage; The inverter voltage is generated according to the bus voltage and the inverter modulation wave.

11. A control device comprising: A working mode determination module is configured to determine a working mode of the converter according to whether at least one of the photovoltaic system and the energy storage system is connected to the converter; A bus voltage establishing module is configured to charge the bus capacitor of the converter through a resistor to establish a bus voltage in the working mode; A compensation amount determination module is configured to determine an angle compensation amount and a voltage compensation amount of the working mode according to the value of the bus voltage, the amplitude, phase and frequency of the grid voltage; The starting control module is configured to compensate the current angle and current voltage of the converter at startup according to the angle compensation amount and voltage compensation amount of the working mode, and start the converter according to the compensated angle and compensated voltage.

12. A control device comprising: a memory configured to store instructions; and The processor is configured to execute the instruction so that the control device implements the converter startup control method according to any one of claims 1 to 10.

13. A converter startup control system, comprising the control device according to claim 11 or 12.

14. The inverter startup control system according to claim 13, further comprising: A photovoltaic system access control circuit, wherein the photovoltaic system access control circuit includes a first charging switch, a first resistor and a first working switch, the first charging switch and the first resistor are connected in series and then in parallel with the first working switch, the first charging switch is configured to, when closed, allow the photovoltaic system to charge the bus capacitor of the converter through the first resistor, and the first working switch is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

15. The converter startup control system according to claim 13 or 14, further comprising: The energy storage system access control circuit includes a second charging switch, a second resistor and a second working switch, the second charging switch and the second resistor are connected in series and then connected in parallel with the second working switch, the second charging switch is configured to, when closed, allow the energy storage system to charge the bus capacitor of the converter through the second resistor, and the second working switch is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

16. The converter startup control system according to claim 13 or 14, further comprising: A power grid access control circuit, wherein the power grid access control circuit includes a first rectifier, a third charging switch, a third resistor and a third working switch, the first rectifier is configured to convert the power grid AC voltage into a DC voltage, the third charging switch and the third resistor are connected in series and in parallel with the third working switch, the third charging switch is configured to, when closed, allow the power grid voltage to charge the bus capacitor of the converter through the first rectifier and the third resistor, and the third working switch is configured to be closed when the bus voltage is established, so that the converter outputs an inverter voltage.

17. The converter startup control system according to claim 13 or 14, further comprising: A first acquisition module is configured to acquire bus voltage; The second acquisition module is configured to acquire the amplitude, phase and frequency of the grid voltage; The third acquisition module is configured to acquire the actual amplitude, actual phase and actual frequency of the inverter voltage.

18. The converter startup control system according to claim 13 or 14, further comprising: An AC switch, wherein the AC switch is arranged between the power grid and the converter; a second acquisition module is configured to collect the amplitude, phase and frequency of the power grid voltage between the power grid and the AC switch; and a third acquisition module is configured to collect the actual amplitude, actual phase and actual frequency of the inverter voltage between the AC switch and the converter.

19. A converter system, comprising the converter startup control system according to any one of claims 13 to 18.

20. An air conditioning system comprising the inverter system according to claim 19.

21. A computer-readable storage medium, wherein: The computer-readable storage medium stores computer instructions, and when the instructions are executed by a processor, the converter startup control method according to any one of claims 1 to 10 is implemented.

22. A computer program product comprising a computer program, wherein: When the computer program is executed by a processor, the converter startup control method according to any one of claims 1 to 10 is implemented.

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