A control method, a new energy converter and a grid-connected power system

Abstract

A grid connection control method of a new energy converter is applied to a new energy converter, the new energy converter comprising a conversion circuit and a controller, an input end of the conversion circuit being used for connecting a direct current source, and an output end of the conversion circuit being used for connecting an alternating current system. The controller transforms a phase of active power after obtaining the active power at the output end of the conversion circuit, and can provide an inertia support feature in active power and frequency closed loop control. The controller quickly controls a voltage parameter at the output end of the conversion circuit according to the active power after phase delay, and can quickly adjust the voltage at the output end of the conversion circuit without affecting the inertia support feature of the inverter.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, and in particular to a control method, a new energy converter and a grid-connected power system. BACKGROUND

[0002] In recent years, the temperature of the world is rising. In order to reduce carbon emissions, clean energy has become the development trend in the future. Clean energy includes solar energy, wind energy, water energy, tidal energy, etc. Generally, clean energy cannot be directly used, and can be converted into electric energy for human use. For example, a photovoltaic power generation system converts solar energy into electric energy, a hydroelectric power generation system converts water energy into electric energy, a wind power generation system converts wind energy into electric energy, and the conversion mode.

[0003] In the prior art, photovoltaic power generation systems, hydroelectric power generation systems and other power generation systems have limitations and cannot provide stable power supply all day long. Therefore, the power generation system of clean energy needs to be integrated into the power grid system for overall scheduling and use by the power grid system. However, the voltage parameters of the power grid system, such as the frequency, phase and amplitude of the voltage, will change with the change of the load. The voltage parameters of the power generation system of clean energy are different from those of the power grid system, which causes the characteristics of low inertia and low short-circuit ratio of the power grid system, and reduces the stability of the power grid system. SUMMARY

[0004] In order to solve the above problems, the embodiments of the present application provide a control method, a new energy converter and a grid-connected power system. After the controller obtains the active power at the output end of the conversion circuit, the phase of the active power is converted, and the inertia support characteristic can be provided in the active power and frequency closed-loop control. The controller controls the voltage parameters at the output end of the conversion circuit according to the active power after the phase delay, so as to adjust the voltage parameters at the output end of the conversion circuit. After the controller receives the power instruction, the active power corresponding to the power instruction is subtracted from the active power after the phase delay to obtain a power difference. The controller can directly control the voltage parameters at the output end of the conversion circuit according to the power difference, so as to improve the speed of the instruction response of the conversion circuit.

[0005] Therefore, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, the embodiments of the present application provide a grid construction control method of a new energy converter, which is applied to the new energy converter. The new energy converter comprises a conversion circuit and a controller. An input end of the conversion circuit is configured to be connected to a direct current source, and an output end of the conversion circuit is configured to be connected to an alternating current system. The method comprises the following steps: the controller is configured to control active power output by the conversion circuit, and delay a phase of the active power when a change value of a voltage frequency of the alternating current system within a set time is greater than a set threshold; and the controller is configured to control a voltage parameter of the output end of the conversion circuit according to the active power after the phase is delayed, so that the conversion circuit outputs active power with inertia support.

[0007] In the embodiment, the controller transforms the phase of the active power after obtaining the active power output by the conversion circuit, so that inertia support characteristics can be provided in active power and frequency closed-loop control. The controller controls the voltage parameter of the output end of the conversion circuit according to the active power after the phase is delayed, so that the voltage of the output end of the conversion circuit can be quickly adjusted without affecting the inertia support characteristics of the inverter.

[0008] In an embodiment, before the controller controls the voltage parameter of the output end of the conversion circuit according to the active power after the phase is delayed, the method further comprises the following steps: receiving a power instruction, the power instruction being configured to control the voltage parameter of the output end of the conversion circuit; and controlling the voltage parameter of the output end of the conversion circuit according to the active power after the phase is delayed, comprising: processing a difference between active power corresponding to the power instruction and the active power after the phase is delayed to obtain a power difference value; and controlling the voltage parameter of the output end of the conversion circuit according to the power difference value.

[0009] In the embodiment, after the controller receives the power instruction, the controller processes a difference between active power corresponding to the power instruction and the active power after the phase is delayed to obtain a power difference value, and then quickly controls the voltage parameter of the output end of the conversion circuit, so that the voltage of the output end of the conversion circuit can be quickly adjusted without affecting the inertia support characteristics of the inverter, and the speed of instruction response of the controller is improved.

[0010] In an embodiment, after the power instruction is received, the method further comprises the following steps: converting the active power corresponding to the power instruction into a given power; when an output voltage of the output end of the conversion circuit is stable, a value of the given power is equal to the active power after the phase is delayed; and processing a difference between the active power corresponding to the power instruction and the active power after the phase is delayed to obtain a power difference value, comprising: processing a difference between the given power and the active power after the phase is delayed to obtain the power difference value.

[0011] In the embodiment, after receiving the power instruction, the controller converts the active power corresponding to the power instruction into the given power, and the value of the given power is the same as the active power after the delay phase when the output voltage of the output end of the conversion circuit is stable. At this time, the power difference value is zero, and the controller can not adjust the output voltage of the output end of the conversion circuit when the output voltage of the output end of the conversion circuit is stable.

[0012] In an embodiment, the voltage parameter includes the frequency of the voltage, and the control of the voltage parameter of the output end of the conversion circuit according to the power difference value includes: converting the power difference value into the frequency of the voltage by using the relationship between the power and the frequency of the synchronous motor.

[0013] In the embodiment, the controller converts the power difference value into the frequency of the voltage, so as to adjust the frequency of the output voltage of the output end of the conversion circuit.

[0014] In an embodiment, the voltage parameter further includes the phase of the voltage, and the control of the voltage parameter of the output end of the conversion circuit according to the power difference value includes: integrating the angular velocity of the voltage to obtain the phase of the voltage; the frequency of the voltage is determined according to the power difference value, and the angular velocity of the voltage is determined according to the frequency of the voltage.

[0015] In the embodiment, the controller integrates the angular velocity of the voltage to obtain the phase of the voltage, so as to adjust the phase of the output voltage of the output end of the conversion circuit.

[0016] In an embodiment, the voltage parameter further includes the amplitude of the voltage, and the control of the voltage parameter of the output end of the conversion circuit according to the power difference value includes: controlling the amplitude of the voltage according to the reactive power, the angular velocity of the voltage, the phase of the voltage, the amplitude rated value and the reactive power rated value; the reactive power is determined according to the output voltage signal and the output current signal, the frequency of the voltage is determined according to the power difference value, the angular velocity of the voltage is determined according to the frequency of the voltage, and the phase of the voltage is determined according to the angular velocity of the voltage.

[0017] In the embodiment, the controller controls the amplitude of the voltage according to the reactive power, the angular velocity of the voltage, the phase of the voltage, the amplitude rated value and the reactive power rated value, so as to adjust the phase of the output voltage of the output end of the conversion circuit.

[0018] In an embodiment, the method further includes: generating a trigger signal according to the voltage parameter, and the trigger signal is used to trigger the power electronic device inside the conversion circuit to adjust the voltage parameter of the output end of the conversion circuit.

[0019] In a second aspect, the embodiments of the present application provide a new energy converter, comprising a conversion circuit and a controller, the controller being configured to control active power output by the conversion circuit, and delay a phase of the active power when a variation of a voltage frequency of an alternating current system within a set time is greater than a set threshold; and control a voltage parameter of an output end of the conversion circuit according to the active power after the phase is delayed, so that the conversion circuit outputs active power with inertia support.

[0020] In an embodiment, the controller is further configured to receive a power instruction, the power instruction being used to control the voltage parameter of the output end of the conversion circuit; and obtain a power difference value by subtracting the active power after the phase is delayed from active power corresponding to the power instruction; and control the voltage parameter of the output end of the conversion circuit according to the power difference value.

[0021] In an embodiment, the controller is further configured to convert the active power corresponding to the power instruction into a given power; when an output voltage of the output end of the conversion circuit is stable, a value of the given power is equal to the active power after the phase is delayed; and obtain the power difference value by subtracting the active power after the phase is delayed from the given power.

[0022] In an embodiment, the voltage parameter comprises a frequency of the voltage, and the controller is specifically configured to convert the power difference value into the frequency of the voltage by using a relationship between power and frequency of a synchronous motor.

[0023] In an embodiment, the voltage parameter further comprises a phase of the voltage, and the controller is specifically configured to integrate an angular velocity of the voltage to obtain the phase of the voltage; the frequency of the voltage is determined according to the power difference value, and the angular velocity of the voltage is determined according to the frequency of the voltage.

[0024] In an embodiment, the voltage parameter further comprises an amplitude of the voltage, and the controller is specifically configured to control the amplitude of the voltage according to reactive power, the angular velocity of the voltage, the phase of the voltage, an amplitude rated value and a reactive power rated value; the reactive power is determined according to an output voltage signal and an output current signal, the frequency of the voltage is determined according to the power difference value, the angular velocity of the voltage is determined according to the frequency of the voltage, and the phase of the voltage is determined according to the angular velocity of the voltage.

[0025] In an embodiment, the controller is further configured to generate a trigger signal according to the voltage parameter, the trigger signal being used to trigger power electronic devices inside the conversion circuit to adjust the voltage parameter of the output end of the conversion circuit.

[0026] In a third aspect, the embodiments of the present application provide a grid-connected power system, comprising: a new energy component, at least one new energy converter as possible in the second aspect, an input end of the new energy converter is connected with the new energy component, and an output end of the new energy converter is used to be connected with a power grid; and the converter is used to convert direct current of the new energy component into alternating current of the power grid, or convert alternating current of the power grid into direct current of the new energy component.

[0027] In a fourth aspect, the embodiments of the present application provide a computer readable storage medium, which stores a computer program, and when the computer program is executed in a computer, the computer program makes the computer execute the embodiments of the first aspect.

[0028] In a fifth aspect, the embodiments of the present application provide a computer program product, characterized in that the computer program product stores instructions, and when the instructions are executed by a computer, the computer executes the embodiments of the first aspect. BRIEF DESCRIPTION OF DRAWINGS

[0029] The drawings needed to be used in the embodiments or the prior art description are briefly introduced as follows.

[0030] Figure 1 It is a schematic diagram of an architecture of a grid-connected power system in the prior art.

[0031] FIG. 2(a) is a schematic diagram of a process of executing an instruction response of a grid-forming control unit in the prior art.

[0032] FIG. 2(b) is a schematic diagram of a process of executing an inertia support response of a grid-forming control unit in the prior art.

[0033] Figure 3 It is a schematic diagram of an architecture of a grid-forming control unit in the prior art.

[0034] Figure 4 It is a schematic diagram of an architecture of a grid-forming control unit in the prior art.

[0035] Figure 5 It is a schematic diagram of an architecture of a controller provided in the embodiments of the present application.

[0036] Figure 6 It is a schematic diagram of a flow of a control method provided in the embodiments of the present application. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings in the embodiments of the present application.

[0038] The term "and / or", used in the present document, is a descriptive association relationship of associated objects, which means that there can be three relationships, for example, A and / or B can represent the following three cases: A exists alone, A and B exist simultaneously, and B exists alone. In the present document, the symbol " / " represents an or relationship of associated objects, for example, A / B represents A or B.

[0039] The terms "first" and "second" and the like in the description and claims of the present document are used to distinguish different objects, rather than to describe a specific order of the objects. For example, the first response message and the second response message are used to distinguish different response messages, rather than to describe a specific order of the response messages.

[0040] In the embodiments of the present application, the words "exemplary" or "for example" are used to mean serving as an example, instance, or illustration, in the embodiments of the present application, any embodiment or design scheme described as "exemplary" or "for example" should not be construed as being more preferred or advantageous than other embodiments or design schemes. Rather, the use of "exemplary" or "for example" is intended to present concepts in a particular manner. In the embodiments of the present application, the word "include" or "comprise" or "contain" or "consist of" means including, but not limited to, in the embodiments of the present application, the word "include" or "comprise" or "contain" or "consist of" should not be interpreted as being more restrictive than the word "comprise".

[0041] In the description of the embodiments of the present application, unless otherwise specified, "a plurality of" means two or more, for example, a plurality of processing units means two or more processing units, and the like; a plurality of elements means two or more elements, and the like.

[0042] When an external power supply system such as a photovoltaic power generation system, a hydroelectric power generation system, a wind power generation system, and a backup power supply is connected to a grid system, an inverter is generally connected in series in the grid system. The inverter can adjust the frequency, phase, and amplitude of the voltage of the external power supply system, so that the voltage parameters of the external power supply system are the same as the voltage parameters of the national power supply system.

[0043] The existing inverters can be divided into grid-following control inverters, grid-forming control inverters, and other types of inverters according to different control logics. Among them, the grid-following control inverter uses a phase-locked loop to make the voltage parameters of the external power supply system the same as the voltage parameters of the national power supply system. The grid-forming control inverter uses a power control method to make the voltage parameters of the external power supply system the same as the voltage parameters of the national power supply system.

[0044] When grid-connected inverter is connected to the grid, the grid-connected inverter will have low or no inertia. When large-scale external power system is connected to the grid, the inertia support of the grid will be reduced. However, the grid-forming inverter will not reduce the inertia support of the grid. Therefore, the grid-forming inverter has more advantages than the grid-connected inverter.

[0045] Figure 1 Figure 1 shows a schematic diagram of a grid-connected power system according to the prior art. The grid-connected power system 100 includes a power system 110, an inverter 120 and an external power system 130. The external power system 130 is connected to the power system 110 through the inverter 120. In other embodiments, the grid-connected power system 100 can include other components such as transformers, inductors, power connection lines, etc., which are not limited in the present application. Figure 1

[0046] The inverter 120 includes a bidirectional DC / AC conversion circuit 121 and a grid-forming control unit 122. The input end of the bidirectional DC / AC conversion circuit 121 is electrically connected to the external power system 130. The output end of the bidirectional DC / AC conversion circuit 121 is electrically connected to the power system 110. The bidirectional DC / AC conversion circuit 121 converts the DC power of the external power system 130 into AC power and inputs it into the power system 110.

[0047] The grid-forming control unit 122 is coupled to the bidirectional DC / AC conversion circuit 121 and is configured to receive the output voltage signal and the output current signal of the output end of the bidirectional DC / AC conversion circuit 121, and the input voltage signal and the input current signal of the input end. The output voltage signal can be the DC voltage of the bidirectional DC / AC conversion circuit 121. The output voltage signal can be the AC voltage of the bidirectional DC / AC conversion circuit 121.

[0048] After receiving the output voltage signal and the output current signal of the bidirectional DC / AC conversion circuit 121, the grid-forming control unit 122 adjusts the voltage parameters of the output end of the bidirectional DC / AC conversion circuit 121 so that the voltage parameters of the output end of the bidirectional DC / AC conversion circuit 121 are the same as the voltage parameters of the power system 110. The voltage parameters can refer to the frequency, phase and amplitude of the voltage.

[0049] ​Figure 2(a) is a schematic diagram of a process of the grid-forming control unit executing a response to an instruction in the prior art. As shown in Figure 2(a), the grid-forming control unit 122 is divided into a grid-forming control synchronization unit 1221, a phase control unit 1222, an amplitude control unit 1223 and a preprocessing unit 1224 according to the functions to be executed.

[0050] The preprocessing unit 1224 receives the output voltage signal and the output current signal of the output end of the bidirectional DC / AC conversion circuit 121 and calculates the active power Pe. The grid-forming control synchronization unit 1221 can receive the active power Pref corresponding to the power instruction sent externally and the active power Pe of the preprocessing unit 1224. The grid-forming control synchronization unit 1221 can determine the relationship between the power and the frequency by analogy with the nonlinear positive relationship between the power and the frequency of the synchronous motor. The grid-forming control synchronization unit 1221 calculates the angular velocity ωsyn of the voltage according to the received active power. The relationship between the angular velocity ω and the frequency f is ω = 2πf. The phase control unit 1222 integrates the angular velocity ωsyn of the voltage after receiving the angular velocity ωsyn of the voltage to obtain the phase θsyn of the voltage. The amplitude control unit 1223 receives parameters such as the angular velocity ωsyn of the voltage and the phase θsyn of the voltage and can calculate the amplitude Ve of the voltage and send a control instruction to the bidirectional DC / AC conversion circuit 121 to allow the bidirectional DC / AC conversion circuit 121 to adjust the voltage parameters of the output voltage of the output end.

[0051] As shown in Figure 2(a), when the grid-forming control unit 122 executes a response to an instruction, the grid-forming control synchronization unit 1221 receives the power instruction sent externally. When the grid-forming control unit 122 receives the active power Pref corresponding to the power instruction, the active power Pe of the output end of the bidirectional DC / AC conversion circuit 121 will change. The grid-forming control synchronization unit 1221 quickly converts the active power Pref into the angular velocity ωsyn of the voltage, so that the output power of the bidirectional DC / AC conversion circuit 121 can quickly respond to the power instruction.

[0052] As shown in Figure 2(b), when the grid-forming control unit 122 executes an inertia support response, the grid-forming control synchronization unit 1221 receives the active power Pe of the preprocessing unit 1224. When the grid-forming control unit 122 receives the active power Pe of the preprocessing unit 1224, the grid-forming control synchronization unit 1221 slowly converts the active power Pe into the angular velocity ωsyn of the voltage, so as to avoid the inverter 120 quickly adjusting the voltage parameters of the output voltage of the output end and reducing the inertia support characteristics of the power system 110.

[0053] The switching speed of the grid-forming control synchronization unit 1221 is opposite when the grid-forming control unit 122 executes the two different control logics of the power instruction response and the inertia support response. If the switching speed of the grid-forming control synchronization unit 1221 is fast, the inertia characteristics of the inverter 100 will be weakened. If the switching speed of the grid-forming control synchronization unit 1221 is slow, the speed of the inverter 100 responding to the power instruction will be reduced. Therefore, the existing grid-forming control unit 122 cannot solve the contradiction between the power instruction response and the inertia support response.

[0054] In order to solve the contradiction between the power instruction response and the inertia support response that the grid-forming control unit 122 cannot solve, two solutions are proposed in the prior art, as follows:

[0055] As shown in Figure 3 , the grid-forming control unit 122 can also include a parameter adaptive adjustment unit 1225. The parameter adaptive adjustment unit 1225 is coupled with the grid-forming control synchronization unit 1221. When the external power supply system 130 is connected to the power system 110, the voltage parameters of the external power supply system 130 and the voltage parameters of the power system 110 are different, and the inverter 100 needs to adjust the voltage parameters of the external power supply system 130.

[0056] After the grid-forming control synchronization unit 1221 receives the power instruction sent by the outside, the power instruction response is executed. When the grid-forming control unit 122 receives the active power Pref corresponding to the power instruction, the active power Pref is sent to the parameter adaptive adjustment unit 1225. The parameter adaptive adjustment unit 1225 generates control parameters according to the active power Pref, the control environment information of the grid-forming control unit 122, and other state quantities. The grid-forming control synchronization unit 1221 can autonomously adjust the speed of the active power Pref converted into the angular speed ωsyn of the voltage according to the control parameters, which can improve the speed of the inverter 100 responding to the power instruction and reduce the inertia support characteristics of the inverter 100.

[0057] When the grid-forming control unit 122 executes the inertia support response, the preprocessing unit 1224 sends the active power Pe to the grid-forming control unit 122. When the voltage parameters of the power system 110 change, the grid-forming control unit 122 receives the change of the active power Pe. The grid-forming control unit 122 sends the active power Pe to the parameter adaptive adjustment unit 1225. The parameter adaptive adjustment unit 1225 generates control parameters according to the active power Pe, the control environment information of the grid-forming control unit 122, and other state quantities. The grid-forming control synchronization unit 1221 can autonomously adjust the speed of the active power converted into the angular speed ωsyn of the voltage according to the control parameters, which can improve the inertia support characteristics of the inverter 100 and reduce the speed of the inverter 100 responding to the power instruction.

[0058] In the prior art, the grid-forming control unit 122 is to increase the parameter adaptive technology path, and the parameter adaptive adjustment unit 1225 generates a control parameter according to active power and environmental factors to adjust the conversion speed of the grid-forming control synchronization unit 1221. The control parameter is in a dynamic change state, so that the active power conversion speed, inertia support characteristics and other characteristics of the inverter 100 will change with the change of the control parameter, thereby reducing the stability of the inverter 100. In addition, the control parameter generated by the parameter adaptive adjustment unit 1225 can be used by the grid-forming control synchronization unit 1221 to autonomously adjust the conversion speed within a certain numerical range. However, in some working conditions, the grid-forming control synchronization unit 1221 is difficult to autonomously adjust the conversion speed when the control parameter exceeds a certain numerical range.

[0059] As shown in Figure 4 The grid-forming control unit 122 can further include an instruction fast compensation unit 1226. The output end of the instruction fast compensation unit 1226 is coupled with the phase control unit 1222 and the amplitude control unit 1223 respectively. When the external power supply system 130 is connected to the power system 110, the voltage parameters of the external power supply system 130 are different from the voltage parameters of the power system 110, and the inverter 100 needs to adjust the voltage parameters of the external power supply system 130.

[0060] After the inverter 120 receives the power instruction, the active power Pref corresponding to the power instruction is sent to the grid-forming control synchronization unit 1221 and the instruction fast compensation unit 1226. After the grid-forming control synchronization unit 1221 receives the power instruction sent by the external power system, the power instruction response is executed. The instruction fast compensation unit 1226 generates frequency compensation, phase compensation and other parameters according to the change amount of the instruction power corresponding to the power instruction and other variables. The grid-forming control synchronization unit 1221 converts the active power into the speed of the angular velocity ωsyn of the voltage and inputs it to the phase control unit 1222. The phase control unit 1222 can perform phase compensation according to the phase compensation amount of the instruction fast compensation unit 1226, or the amplitude control unit 1223 can perform frequency compensation according to the frequency compensation amount of the instruction fast compensation unit 1226, and other ways, which can improve the speed of the inverter 100 responding to the power instruction. However, the inertia support characteristics of the inverter 100 will be weakened.

[0061] In order to solve the defects of the existing inverter, the embodiment of the present application provides a new energy converter, a control method and a grid-connected power system.

[0062] Figure 5 A structural schematic diagram of a new energy converter provided by the embodiment of the present application is shown in Figure 5As shown, the new energy converter 500 includes a conversion circuit 510 and a controller 520. In this application, one end of the new energy converter 500 is electrically connected to an external power supply system, and the other end of the converter 500 is electrically connected to a power system.

[0063] In one embodiment, the new energy converter 500 can be an inverter, a rectifier, a modular multilevel converter or other converter. In other embodiments, the new energy converter 500 can be a bidirectional converter.

[0064] In one embodiment, the external power supply system can be a backup power supply, a photovoltaic power generation system, a hydroelectric power generation system, a wind power generation system or other power supply system.

[0065] In one embodiment, the power system can be a power grid system, a home power grid, an enterprise power grid or other power system.

[0066] The conversion circuit 510 includes a bidirectional DC / AC conversion circuit for converting alternating current into direct current or converting direct current into alternating current. In one embodiment, the voltage of the external power supply system is direct current, and the voltage of the power system is alternating current. The conversion circuit 510 converts the direct current of the external power supply system into alternating current with a set voltage value. In other embodiments, the conversion circuit 510 can be other types of conversion circuits, which are not limited in this application.

[0067] The controller 520 can be a digital signal processing (DSP) unit, a field programmable gate array (FPGA), a microcontroller unit (MCU) or other devices with computing and control functions. In this application, the controller 520 receives the output voltage signal U1 and the output current signal I1 of the output end of the conversion circuit 510, and the input voltage signal U2 and the input current signal I2 of the input end, and adjusts the voltage parameter of the output voltage of the output end of the conversion circuit 510. The controller 520 receives the power instruction input externally, and adjusts the voltage parameter of the output voltage of the output end of the conversion circuit 510 according to the active power corresponding to the power instruction, the output voltage signal U1 and the output current signal I1 of the output end of the conversion circuit 510, and the input voltage signal U2 and the input current signal I2 of the input end. The voltage parameter can be the frequency fsyn of the voltage, the phase θsyn of the voltage and the amplitude Ve of the voltage.

[0068] In the embodiments of the present application, the controller 520 can be divided into a preprocessing unit 521, an inertia control unit 522, an instruction adjustment unit 523, a subtractor 524, a forward control unit 525, a phase control unit 526, an amplitude control unit 527 and a modulation unit 528 according to the functions performed. The preprocessing unit 521, the inertia control unit 522, the instruction adjustment unit 523, the subtractor 524, the forward control unit 525, the phase control unit 526, the amplitude control unit 527 and the modulation unit 528 can be implemented by software, or can be implemented by hardware, or can be implemented by a combination of software and hardware.

[0069] The preprocessing unit 521 is configured to receive the output voltage signal U1 and the output current signal I1 of the output end of the conversion circuit 510. The preprocessing unit 521 is further configured to calculate the active power Pe and the reactive power Qe according to the output voltage signal U1 and the output current signal I1, and input the active power Pe to the inertia control unit 522 and input the reactive power Qe to the amplitude control unit 527. The active power Pe and the reactive power Qe can be average power or instantaneous power. For average power, the active power Pe refers to the alternating current energy actually emitted or consumed per unit time, which is the average power in a period; the reactive power Qe refers to the energy absorbed from the power supply by the electric field or magnetic field in an alternating current circuit with reactance in a part of a period, and the energy is released in another part of the period, and the average power is zero in the whole period, but the energy is exchanged between the power supply and the reactance element (capacitor, inductor) without stop. The maximum value of the exchange rate is the reactive power Qe. For instantaneous power, its size is equal to the product of the instantaneous values of instantaneous voltage and current. The instantaneous power of alternating current is not a constant value, and the average value of the instantaneous power in a period is called active power, so the active power is also called average power.

[0070] In the embodiments of the present application, the conversion circuit 510 further includes a sampling module. The sampling module samples the output voltage and the output current of the output end to obtain the output voltage and the output current. The sampling module converts the output voltage and the output current into digital signals to obtain the output voltage signal U1 and the output current signal I1, and inputs the output voltage signal U1 and the output current signal I1 to the controller 520. The sampling module samples the input voltage and the input current of the input end to obtain the input voltage and the input current. The sampling module converts the input voltage and the input current into digital signals to obtain the input voltage signal U2 and the input current signal I2, and inputs the input voltage signal U2 and the input current signal I2 to the controller 520.

[0071] The conversion circuit 510 can be a bidirectional conversion circuit. In one embodiment, the input end of the conversion circuit 510 is an external power supply system, and the output end of the conversion circuit 510 is a power system. The output voltage is an alternating voltage, the output current is an alternating current, the input voltage is a direct voltage, and the input current is a direct current. In one embodiment, the input end of the conversion circuit 510 is a power system, and the output end of the conversion circuit 510 is an external power supply system. The output voltage is a direct voltage, the output current is a direct current, the input voltage is an alternating voltage, and the input current is an alternating current.

[0072] The inertia control unit 522 can be a combination of one or more functions of a proportional function, an integral equation, a first-order low-pass filter, a multi-order low-pass filter, etc. When the voltage frequency or voltage phase of the power system fluctuates, the power system will cause the output power of the output end of the conversion circuit 510 to fluctuate. The inertia control unit 522 can transform the phase of the active power Pe to obtain the delayed phase of the active power Peic. At the same time, when the inertia control unit 522 transforms the phase of the active power Pe, the amplitude of the active power Pe changes. In this application, the inertia control unit 522 transforms the amplitude and phase of the active power Pe, delays the phase of the active power Pe, and changes the amplitude of the active power Pe. The inertia control unit 522 provides inertia support characteristics for the new energy converter 500 in the active power and frequency closed-loop control.

[0073] In one embodiment, the inertia control of the inertia control unit 522 can be equivalent to a first-order low-pass filter of a swing equation. The active power Pe is input into the first-order low-pass filter, and the first-order low-pass filter can change the amplitude of the active power Pe according to the stable parameter 1 / K D The conversion transforms the amplitude and phase of the active power Pe, delays the phase of the active power Pe, and changes the amplitude of the active power Pe.

[0074] The instruction adjustment unit 523 can be a combination of one or more functions of a proportional function, an integral equation, a rotor motion equation, a first-order low-pass filter, a multi-order low-pass filter, etc. The instruction adjustment unit 523 is used to process the active power Pref corresponding to the input power instruction, and convert the active power Pref corresponding to the power instruction into a given power Prefa. When the output voltage of the output end of the conversion circuit 510 is stable, that is, the control system is in a stable state. The given power Prefa output by the instruction adjustment unit 523 is the same as the delayed phase of the active power Peic output by the inertia control unit 522.

[0075] In one embodiment, the instruction adjustment unit 523 is a proportional function, and the instruction adjustment unit 523 divides the active power Pref corresponding to the power instruction by a set proportional value to obtain the given power Prefa.

[0076] In one embodiment, the instruction adjustment unit 523 is a first-order low-pass filter, and the instruction adjustment unit 523 filters the active power Pref corresponding to the power instruction to convert the active power Pref corresponding to the power instruction into the given power Prefa.

[0077] The subtracter 524 is configured to receive the given power Prefa output by the instruction adjustment unit 523 and the delayed active power Peic output by the inertia control unit, and to perform a difference operation on the given power Prefa and the delayed active power Peic to obtain a power difference value ΔP.

[0078] The forward control unit 525 can be a combination of one or more functions of a proportional function, a differential equation, a low-pass filter, a high-pass filter, a lead / lag correction function, etc. The forward control unit 525 can determine the relationship between the power and the frequency by analogy with the nonlinear positive relationship between the power and the frequency of the synchronous motor. After receiving the power difference value ΔP, the forward control unit 525 converts the power difference value ΔP into the angular velocity ωsyn of the voltage by using the relationship between the power and the frequency, and outputs the angular velocity ωsyn of the voltage to the phase control unit 526, the amplitude control unit 527, and the modulation unit 528.

[0079] In one embodiment, the forward control unit 525 is a combination of a proportional function, a differential equation, and a low-pass filter, and the forward control unit 525 divides the power difference value ΔP by a set proportional value, differentiates, and filters to obtain the angular velocity ωsyn of the voltage corresponding to the power difference value ΔP.

[0080] The phase control unit 526 can be an integrator or a combination of an integrator and other devices. After receiving the angular velocity ωsyn of the voltage, the phase control unit 526 integrates the angular velocity ωsyn of the voltage to obtain the phase θsyn of the voltage, and outputs the phase θsyn of the voltage to the amplitude control unit 527 and the modulation unit 528.

[0081] The amplitude control unit 527 can be a combination of one or more functions of a proportional function, an integral equation, a proportional integral equation, etc. After receiving the reactive power Qe of the pre-processing unit 521, the angular velocity ωsyn of the voltage of the forward control unit 525, the phase θsyn of the voltage of the phase control unit 526, the amplitude rating value Vref input from the outside, the reactive power rating value Qref input from the outside, etc., the amplitude control unit 527 can control the amplitude Ve of the voltage, and outputs the amplitude Ve of the voltage to the modulation unit 528.

[0082] The modulation unit 528 receives the angular velocity ωsyn of the voltage, the phase θsyn of the voltage, and the amplitude Ve of the voltage, and generates a trigger signal according to the angular velocity ωsyn of the voltage, the phase θsyn of the voltage, and the amplitude Ve of the voltage. The relationship between the angular velocity ω and the frequency f is ω = 2πf, and the frequency fsyn of the voltage can be obtained according to the angular velocity ωsyn of the voltage. After the conversion circuit 510 receives the trigger signal, the power electronic devices inside the conversion circuit 510 can be controlled to work, so as to adjust the frequency of the output voltage, the phase of the output voltage, and the amplitude of the output voltage of the output end of the conversion circuit 510.

[0083] In the embodiment of the application, after the controller 520 receives the output voltage signal U1 and the output current signal I1 of the conversion circuit 510, the output voltage signal U1 and the output current signal I1 are input into the preprocessing unit 521, so that the preprocessing unit 521 calculates the active power Pe and the reactive power Qe. The inertia control unit 522 transforms the amplitude and the phase of the active power Pe to obtain the delayed-phase active power Peic, so as to realize the closed-loop control of the active power and the frequency, and provide the inertia support feature for the new energy converter 500.

[0084] When the voltage parameter of the power system does not change, the active power Pe calculated by the preprocessing unit 521 is 0. The control system does not need to provide the inertia support feature for the power system. When the voltage parameter of the power system changes, the controller 520 realizes the function of the inertia support response. The inertia control unit 522 delays the phase of the active power Pe and changes the amplitude of the active power Pe, so as to provide the inertia support feature for the new energy converter 500 in the closed-loop control of the active power and the frequency.

[0085] The controller 520 also receives a power instruction. After the instruction adjustment unit 523 receives the power instruction, the active power Pref corresponding to the power instruction is converted into the given power Prefa. The power difference △P input into the forward control unit 525 by the subtractor 524 is the difference between the given power Prefa and the delayed-phase active power Peic.

[0086] The forward control unit 525 quickly converts the power difference △P into the voltage ω. The phase control unit 526 receives the angular velocity ω of the voltage, integrates the angular velocity ω of the voltage, and obtains the phase θ of the voltage. After the amplitude control unit 527 receives the reactive power Qe, the angular velocity ω of the voltage, the phase θ of the voltage, the amplitude rated value Vref input from the outside, the reactive power rated value Qref input from the outside, and other parameters, the amplitude of the voltage Ve can be controlled. The modulation unit 528 generates a trigger signal according to the angular velocity ω of the voltage, the phase θ of the voltage, and the amplitude Ve of the voltage.

[0087] When the trigger signal is received, the conversion circuit 510 can control the power electronic devices inside the conversion circuit 510 to act, so that the power electronic devices inside the conversion circuit 510 adjust the frequency, phase and amplitude of the output voltage of the output end of the conversion circuit 510.

[0088] In this embodiment, after the controller 520 receives the power instruction sent by the outside, the power instruction response is executed. The instruction adjustment unit 523 and the forward control unit 525 can quickly adjust the synchronous angular velocity of the voltage, so that the controller 520 can quickly adjust the trigger information. After receiving the trigger information, the conversion circuit 510 can quickly adjust the voltage parameters of the output voltage of the output end of the conversion circuit 510, so as to improve the speed of the instruction response of the conversion circuit 510.

[0089] In one embodiment, the controller 520 does not receive the power instruction, or the active power Pref corresponding to the power instruction is 0. The voltage of the power system is unstable, and the active power Pe calculated by the preprocessing unit 521 is ≠0. The power difference △P input to the forward control unit 525 by the subtracter 524 is △P=-Peic. At this time, the controller 520 provides inertia support characteristics for the power system, and adjusts the voltage parameters of the output voltage of the output end of the conversion circuit 510, so that the voltage parameters of the output voltage of the output end of the conversion circuit 510 follow the change of the voltage parameters of the power system.

[0090] In one embodiment, the controller 520 does not receive the power instruction, or the active power Pref corresponding to the power instruction is 0. The voltage of the power system is stable, and the active power Pe calculated by the preprocessing unit 521 is 0. The power difference △P input to the forward control unit 525 by the subtracter 524 is △P=0. At this time, the controller 520 adjusts the voltage parameters of the output voltage of the output end of the conversion circuit 510 to tend to be stable.

[0091] In one embodiment, the controller 520 receives the power instruction, and the active power Pref corresponding to the power instruction is ≠0. The power difference △P input to the forward control unit 525 by the subtracter 524 is △P=Prefa-Peic. At this time, the controller 520 provides inertia support characteristics for the power system according to the active power of the preprocessing unit 521. And the controller 520 quickly adjusts the voltage parameters of the output voltage of the output end of the conversion circuit 510 according to the active power corresponding to the power instruction and the active power of the preprocessing unit 521, so that the voltage parameters of the output voltage of the output end of the conversion circuit 510 follow the change of the voltage parameters of the power system.

[0092] In the embodiments of the present application, the instruction adjustment unit 523 and the forward control unit 525 act on a short time scale, which can accelerate the response speed of the instruction. The inertia control unit 522 acts on a long time scale, which can provide inertia support characteristics.

[0093] Figure 6 A flowchart of a control method provided in the embodiments of the present application is shown in FIG. 6. As shown in FIG. 6, the control method is executed by the controller 520, and the specific process is as follows. Figure 6

[0094] In step S601, the controller 520 receives the output voltage signal and the output current signal of the conversion circuit 510.

[0095] Specifically, one end of the conversion circuit 510 is electrically connected to an external power supply system, and the other end of the conversion circuit 510 is electrically connected to a power system. The conversion circuit 510 converts alternating current into direct current, or converts direct current into alternating current. A sampling module inside the conversion circuit 510 samples the output voltage and the output current of the output end to obtain the output voltage and the output current. The sampling module samples the input voltage and the input current of the input end to obtain the input voltage and the input current.

[0096] In one embodiment, the sampling module converts the output voltage, the output current, the input voltage, and the input current into digital signals to obtain the output voltage signal U1, the output current signal I1, the input voltage signal U2, and the input current signal I2, and inputs the output voltage signal U1, the output current signal I1, the input voltage signal U2, and the input current signal I2 into the controller 520.

[0097] In step S602, the controller 520 calculates the active power and the reactive power according to the output voltage signal and the output current signal.

[0098] Specifically, after receiving the output voltage signal U1 and the output current signal I1 of the conversion circuit 510, the controller 520 calculates the active power Pe and the reactive power Qe according to the output voltage signal U1 and the output current signal I1.

[0099] In one embodiment, the controller 520 includes a preprocessing unit 521. The preprocessing unit 521 is configured to receive the output voltage signal U1, the output current signal I1, the input voltage signal U2, and the input current signal I2 of the conversion circuit 510. The preprocessing unit 521 is further configured to calculate the active power Pe and the reactive power Qe according to the output voltage signal U1 and the output current signal I1, and input the active power Pe to the inertia control unit 522 and input the reactive power Qe to the amplitude control unit 527.

[0100] ​Step S603, the controller 520 delays the phase of the active power, and obtains the active power after the phase is delayed.

[0101] Specifically, the controller 520 transforms the amplitude and the phase of the active power Pe, and obtains the active power Peic after the phase is delayed. The controller 520 processes the amplitude and the phase of the active power Pe, delays the phase of the active power Pe, and changes the amplitude of the active power Pe.

[0102] In an embodiment, the controller 520 includes an inertia control unit 522. When the voltage frequency or the voltage phase of the power system fluctuates, the power system causes the output power of the output end of the conversion circuit 510 to fluctuate. The inertia control unit 522 can transform the amplitude and the phase of the active power Pe, and obtain the active power Peic after the phase is delayed. The inertia control unit 522 provides inertia support characteristics for the new energy converter 500 in the active power and frequency closed loop control.

[0103] Step S604, the controller 520 calculates the power difference value between the active power after the phase is delayed and the given power.

[0104] Specifically, when the controller 520 receives the power instruction, the controller 520 can process the difference between the active power corresponding to the power instruction and the active power after the phase is delayed, and calculate the power difference value. When the controller 520 does not receive the power instruction, the controller 520 can take the active power after the phase is delayed as the power difference value.

[0105] In an embodiment, the controller 520 includes an instruction adjustment unit 523. The instruction adjustment unit 523 is configured to process the active power Pref corresponding to the input power instruction, and convert the active power Pref corresponding to the power instruction into the given power Prefa. When the output voltage of the output end of the conversion circuit 510 is stable, that is, the control system is in a stable state. The given power Prefa output by the instruction adjustment unit 523 is the same as the active power Peic output by the inertia control unit 522 after the phase is delayed.

[0106] In an embodiment, the controller 520 does not receive the power instruction, or the active power Pref corresponding to the power instruction is 0. The voltage of the power system is unstable, and the active power Pe calculated by the preprocessing unit 521 is not 0. The power difference value input to the forward control unit 525 by the subtracter 524 is ΔP=-Peic.

[0107] In one embodiment, the controller 520 does not receive the power instruction, or the active power Pref corresponding to the power instruction is 0. The voltage of the power system is stable, the active power Pe calculated by the preprocessing unit 521 is 0. The power difference △P input to the forward control unit 525 by the subtractor 524 is 0.

[0108] In one embodiment, the controller 520 receives the power instruction, and the active power Pref corresponding to the power instruction is not 0. The power difference △P input to the forward control unit 525 by the subtractor 524 is Prefa-Peic.

[0109] Step S605, the controller 520 converts the frequency of the voltage according to the power difference by using the relationship between the power and the frequency of the synchronous motor.

[0110] Specifically, the controller 520 can determine the relationship between the power and the frequency by analogy with the nonlinear positive relationship between the power and the frequency of the synchronous motor. After receiving the power difference △P, the forward control unit 525 converts the power difference △P into the frequency of the voltage by using the relationship between the power and the frequency.

[0111] In one embodiment, the controller 520 includes the forward control unit 525. After receiving the power difference △P, the forward control unit 525 quickly converts the power difference △P into the angular velocity ωsyn of the voltage by using the relationship between the power and the frequency of the synchronous motor, and outputs the angular velocity ωsyn of the voltage to the phase control unit 526, the amplitude control unit 527 and the modulation unit 528. The relationship between the angular velocity ω and the frequency f is ω=2πf, and the frequency fsyn of the voltage can be obtained according to the angular velocity ωsyn of the voltage.

[0112] Step S606, the controller 520 integrates the angular velocity of the voltage to obtain the phase of the voltage.

[0113] In one embodiment, the controller 520 includes the phase control unit 526. After receiving the angular velocity ωsyn of the voltage, the phase control unit 526 integrates the angular velocity ωsyn of the voltage to obtain the phase θsyn of the voltage, and outputs the phase θsyn of the voltage to the amplitude control unit 527 and the modulation unit 528.

[0114] Step S607, the controller 520 controls the amplitude of the voltage according to the reactive power, the angular velocity of the voltage, the phase of the voltage, the amplitude rating and the reactive power rating.

[0115] In one embodiment, the controller 520 comprises an amplitude control unit 527. The amplitude control unit 527 receives the reactive power Qe of the pre-processing unit 521, the angular velocity ωsyn of the voltage of the forward control unit 525, the phase θsyn of the voltage of the phase control unit 526, the amplitude reference value Vref input from the outside, the reactive power reference value Qref input from the outside, and the like, and can control the amplitude Ve of the voltage and output the amplitude Ve of the voltage to the modulation unit 528.

[0116] In step S608, the controller 520 generates a trigger signal according to the angular velocity of the voltage, the phase of the voltage, and the amplitude of the voltage. The trigger signal allows the conversion circuit 510 to adjust the voltage parameters of the output voltage of the output end.

[0117] In one embodiment, the controller 520 comprises a modulation unit 528. The modulation unit 528 receives the angular velocity ωsyn of the voltage, the phase θsyn of the voltage, and the amplitude Ve of the voltage, and generates a trigger signal according to the angular velocity ωsyn of the voltage, the phase θsyn of the voltage, and the amplitude Ve of the voltage. The relationship between the angular velocity ω and the frequency f is ω = 2πf, and the frequency fsyn of the voltage can be obtained according to the angular velocity ωsyn of the voltage. After receiving the trigger signal, the conversion circuit 510 can control the power electronic devices inside the conversion circuit 510 to work, so as to adjust the frequency of the output voltage of the output end of the conversion circuit 510, the phase of the output voltage, and the amplitude of the output voltage.

[0118] In the embodiments of the present application, after obtaining the active power of the output end of the conversion circuit, the controller transforms the amplitude and the phase of the active power to obtain the active power after the delay phase, and can provide inertia support characteristics in the active power and frequency closed-loop control. The controller controls the voltage parameters of the output end of the conversion circuit according to the active power after the delay phase, so as to adjust the voltage parameters of the output end of the conversion circuit. After receiving the power instruction, the controller processes the difference between the active power corresponding to the power instruction and the active power after the delay phase to obtain a power difference value. The controller can directly control the voltage parameters of the output end of the conversion circuit according to the power difference value, so as to quickly control the voltage parameters of the output end of the conversion circuit and improve the speed of the instruction response of the conversion circuit.

[0119] In the embodiments of the present application, a grid-connected power system is also provided, which comprises a first power system, a second power system, and at least one new energy converter. The first power system can be a backup power supply, a photovoltaic power generation system, a hydraulic power generation system, a wind power generation system, or other power supply systems. The second power system can be a grid system, a household power grid, an enterprise power grid, or other power systems. The new energy converter can perform the functions of the controller 520 and the conversion circuit 510 as described above. Figures 5-6 The corresponding technical solutions described above make the grid-connected power system have the technical effects of the protection technical solutions described above.

[0120] The embodiments of the present application also provide a computer program product containing instructions. The computer program product can be a software or program product containing instructions, which can run on a computing device or be stored in any available medium. When the computer program product runs on at least one computing device, the at least one computing device is caused to perform the control method.

[0121] The embodiments of the present application also provide a computer readable storage medium. The computer readable storage medium can be any available medium that the computing device can store or a data storage device such as a data center containing one or more available media. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a DVD), or a semiconductor medium (for example, a solid state disk), etc. The computer readable storage medium contains instructions, which instruct the computing device to perform the control method.

[0122] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the protection scope of the technical solutions of the embodiments of the present application.

Claims

1. A grid-connection control method for a new energy converter, applied in a new energy converter, characterized in that, The new energy converter includes a conversion circuit and a controller. The input terminal of the conversion circuit is used to connect to a DC source, and the output terminal is used to connect to an AC system. The method includes: The controller controls the conversion circuit to output active power; When the change in voltage frequency of the AC system within a set time exceeds a set threshold, the controller performs inertia support processing on the active power to generate active power with a delayed phase. The controller receives power commands; The controller calculates the difference between the given power converted from the power command and the active power of the delayed phase to obtain a power difference value. The controller controls the voltage parameters at the output of the conversion circuit based on the power difference, so that the conversion circuit outputs active power with inertia support. The power command is used to control the voltage parameters at the output of the conversion circuit.

2. The method according to claim 1, characterized in that, The controller calculates the difference between the given power converted from the power command and the active power of the delayed phase to obtain a power difference value, including: The active power corresponding to the power command is converted into a given power; when the output voltage of the output terminal of the conversion circuit is stable, the value of the given power is equal to the active power after the delay phase. The power difference is obtained by subtracting the given power from the active power after the delay phase.

3. The method according to claim 1 or 2, characterized in that, The voltage parameter includes the frequency of the voltage. The step of controlling the voltage parameters at the output of the conversion circuit based on the power difference includes: By utilizing the relationship between the power and frequency of a synchronous motor, the power difference is converted into the frequency of the voltage.

4. The method according to claim 1 or 2, characterized in that, The voltage parameters also include the phase of the voltage. The step of controlling the voltage parameters at the output of the conversion circuit based on the power difference includes: The phase of the voltage is obtained by integrating the angular velocity of the voltage; the frequency of the voltage is determined based on the power difference, and the angular velocity of the voltage is determined based on the frequency of the voltage.

5. The method according to claim 1 or 2, characterized in that, The voltage parameters also include the voltage amplitude. The step of controlling the voltage parameters at the output of the conversion circuit based on the power difference includes: The voltage amplitude is controlled based on the reactive power, the voltage angular velocity, the voltage phase, the rated amplitude, and the rated reactive power; the reactive power is determined based on the output voltage signal and the output current signal; the voltage frequency is determined based on the power difference; the voltage angular velocity is determined based on the voltage frequency; and the voltage phase is determined based on the voltage angular velocity.

6. The method according to claim 1 or 2, characterized in that, The method further includes: Based on the voltage parameters, a trigger signal is generated, which is used to trigger the internal power electronic devices of the conversion circuit to adjust the voltage parameters at the output terminal of the conversion circuit.

7. A new energy converter, characterized in that, It includes a conversion circuit and a controller. The input terminal of the conversion circuit is used to connect to a DC source, and the output terminal is used to connect to an AC system. The controller is used to control the output active power of the conversion circuit, and when the change value of the voltage frequency of the AC system within a set time is greater than a set threshold, the controller performs inertia support processing on the active power to generate active power with delayed phase. Receive a power command, and calculate the difference between the given power converted from the power command and the active power of the delayed phase. The power difference is obtained; Based on the power difference, the voltage parameters at the output of the conversion circuit are controlled so that the conversion circuit outputs active power with inertia support. The power command is used to control the voltage parameters at the output of the conversion circuit.

8. The new energy converter according to claim 7, characterized in that, The controller is further configured to convert the active power corresponding to the power command into a given power; when the output voltage of the output terminal of the conversion circuit is stable, the value of the given power is equal to the active power after the delay phase; The power difference is obtained by subtracting the given power from the active power after the delay phase.

9. The new energy converter according to claim 7 or 8, characterized in that, The voltage parameter includes the frequency of the voltage. The controller is specifically used to convert the power difference into the frequency of the voltage by utilizing the relationship between the power and frequency of the synchronous motor.

10. The new energy converter according to claim 7 or 8, characterized in that, The voltage parameters also include the phase of the voltage. The controller is specifically used to integrate the angular velocity of the voltage to obtain the phase of the voltage; the frequency of the voltage is determined based on the power difference, and the angular velocity of the voltage is determined based on the frequency of the voltage.

11. The new energy converter according to claim 7 or 8, characterized in that, The voltage parameters also include the voltage amplitude. The controller is specifically used to control the amplitude of the voltage based on the reactive power, the angular velocity of the voltage, the phase of the voltage, the rated amplitude, and the rated reactive power; the reactive power is determined based on the output voltage signal and the output current signal, the frequency of the voltage is determined based on the power difference, the angular velocity of the voltage is determined based on the frequency of the voltage, and the phase of the voltage is determined based on the angular velocity of the voltage.

12. The new energy converter according to claim 7 or 8, characterized in that, The controller is further configured to generate a trigger signal based on the voltage parameters, the trigger signal being used to trigger the internal power electronic devices of the conversion circuit to adjust the voltage parameters at the output terminal of the conversion circuit.

13. A grid-connected power system, characterized in that, include: New energy components At least one new energy converter as described in any one of claims 7-12, wherein the input terminal of the new energy converter is connected to a new energy component, the output terminal of the new energy converter is used to connect to the power grid, and the converter is used to convert the direct current of the new energy component into the alternating current of the power grid, or to convert the alternating current of the power grid into the direct current of the new energy component.

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