Energy storage converter system configuration method and system

Abstract

The invention relates to an energy storage converter system configuration method, which comprises the following steps of: respectively acquiring converter current and converter voltage output by a PCS (Power Control System), grid-side current and grid-side voltage, and an inductance value of a power element in the PCS, and outputting a first voltage instruction and a second voltage instruction; calculating an instantaneous active power value and an instantaneous reactive power value according to the collected grid-side current and grid-side voltage; outputting a voltage amplitude and a power angle according to the network side voltage, the active power reference value, the reactive power reference value, the instantaneous active power value and the instantaneous reactive power value; outputting an SPWM instruction according to the second voltage instruction, the first voltage instruction, the voltage amplitude and the power angle; and S5, controlling the PCS according to the SPWM instruction, and the method has the beneficial effects that by introducing the VSG algorithm module, the problem that the power electronic converter does not have the mechanical inertia and damping characteristics of a traditional synchronous generator and cannot provide inertia and damping for a system is solved.

Description

[0001] The present invention belongs to the field of energy storage converters, and in particular relates to an energy storage converter system configuration method and system. Background Art

[0002] Energy storage technology is an important means to improve the absorption of smart grids and increase the capacity of renewable energy generation. It is one of the key technologies supporting the construction of smart grids. When the energy storage system is connected to the grid, it can be charged from the grid or discharged to the grid. When the grid fails, the energy storage system needs to switch from the grid to the off-grid state. With the development of science and technology and the increase in the proportion of renewable energy in total energy utilization, more and more distributed energy is connected to the grid through power electronic inverters. However, power electronic converters have a fast response speed and do not have the mechanical inertia and damping characteristics of traditional synchronous generators. They cannot provide inertia and damping for the system. Excessive access will cause the system's inertia level to be significantly reduced, and the anti-disturbance ability will be weakened. In severe cases, it may even cause the relay equipment to malfunction. Summary of the invention

[0003] The purpose of the present invention is to design a configuration method for an energy storage converter system.

[0004] The specific technical solution of the present invention is as follows: A method for configuring an energy storage converter system includes:

[0005] S1: Collect the converter current I output by PCS pcs and converter voltage U pcs , grid-side current I abc and grid-side voltage U abc , and the inductance value L of the power element in the PCS, according to the converter current I pcs and converter voltage U pcs , grid-side current I abc and grid-side voltage U abc and the inductance value L of the power element in the PCS outputs a first voltage command and a second voltage command;

[0006] S2: Based on the collected grid-side current I abc and grid voltage U abc , calculate the instantaneous active power value P and the instantaneous reactive power value Q;

[0007] S3: According to the grid side voltage U abc , Active power reference value P ref and reactive power reference value Q ref , the instantaneous active power value P and the instantaneous reactive power value Q, the output voltage amplitude E and the power angle δ;

[0008] S4: outputting an SPWM instruction according to the second voltage instruction, the first voltage instruction, the voltage amplitude E and the power angle δ;

[0009] S5: Control the PCS according to the SPWM instruction.

[0010] As an improvement, the step of outputting the first voltage instruction in S1 specifically includes:

[0011] According to the grid-side voltage U abc And the grid-side current I abc Calculate output power;

[0012] According to the converter current I pcs , calculate the active current I 有功 ;

[0013] According to the preset reference power and the output power, an active current instruction is obtained through PI control of an active current instruction calculation module;

[0014] According to the active current command and active current I 有功 , the first voltage instruction is obtained through PI control of the first voltage instruction calculation module.

[0015] As a further improvement, the step of outputting the second voltage instruction in S1 specifically includes:

[0016] Receiving the converter current I pcs , calculate the reactive current I 无功 ;

[0017] Calculating an inductance difference according to an inductance value L of a power element in the PCS and a preset standard inductance;

[0018] According to the grid-side current I abc and grid voltage U abc , calculate the phase of the grid voltage and the amplitude of the grid voltage;

[0019] According to the reactive current I 无功 , calculate the voltage reference value U 参考 and current reference value I 参考 ;

[0020] According to the reactive current I 无功 , voltage reference value U 参考 and current reference value I 参考 The compensation voltage U is calculated by the compensation voltage algorithm based on the phase and amplitude and the inductance value L of the power element in the PCS. 补偿 ;

[0021] According to the voltage reference value U 参考 And compensation voltage U 补偿 , the voltage reference value U 参考 And the compensation voltage U补偿 The second voltage instruction is obtained by adding the two voltages, and the second voltage instruction is output.

[0022] As a further improvement, the compensation voltage algorithm includes an XYZ algorithm, and the XYZ algorithm is:

[0023] Inductance difference × reactive current I 无功 ×k=compensation voltage U 补偿

[0024]

[0025] As a further improvement, the voltage of S3 is determined according to the grid-side voltage U abc , Active power reference value P ref and reactive power reference value Q ref , instantaneous active power value P and instantaneous reactive power value Q, output voltage amplitude E and power angle δ, including:

[0026] According to the active power reference value P ref and the angular velocity reference value ω 0 , instantaneous active power value P and grid-side voltage angular velocity ω g , calculate the active power compensation value P m ;

[0027] According to the active power compensation value P m And reactive power reference value Q ref and grid voltage U abc , calculated by VSG algorithm, the voltage amplitude E and power angle δ are output.

[0028] As a further improvement, the VSG algorithm comprises the following steps:

[0029] According to the active power compensation value P m , calculate the compensation angular velocity ω through the rotor motion equation;

[0030] According to the compensation angular velocity ω, an output power angle δ is output;

[0031] According to the reactive power reference value Q ref and grid voltage U abc , calculated by the excitation equation, the output voltage amplitude E.

[0032] As a further improvement, the rotor motion equation is:

[0033]

[0034] In formula (1), P D , P m and P care the damping power, mechanical power and electromagnetic power of the synchronous generator respectively; J is the moment of inertia; D is the damping coefficient; ω 0 is the synchronous angular velocity of the power grid, and ω is the mechanical angular velocity of the synchronous generator.

[0035] As a further improvement, the excitation equation is:

[0036]

[0037] In formula (2), L is the synchronous reactance, r is the armature resistance, e is abc is the internal potential of VSG, u abc is the terminal voltage of VSG, i abc is the output current of VSG.

[0038] e abc =E[sinθsin(θ-2π / 3)sin(θ+2π / 3)] (3)

[0039] θ is the phase of VSG, θ=∫ωdt; E is the internal potential amplitude.

[0040] The present invention also provides a system, which includes at least one processor; and a memory storing instructions, and when the instructions are executed by the at least one processor, the steps of the above method are implemented.

[0041] The present invention also provides a computer program product, comprising a computer program / instruction, characterized in that the computer program / instruction implements the steps of the aforementioned method when executed by a processor.

[0042] The beneficial effect of the present invention is that it solves the problem that the power electronic converter does not have the mechanical inertia and damping characteristics of the traditional synchronous generator and cannot provide inertia and damping for the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a schematic diagram of a parallel energy storage system converter in the prior art;

[0044] Figure 2 is a schematic diagram of an energy storage converter system of the present invention;

[0045] Figure 3 A schematic diagram of a reactive algorithm module of an energy storage converter system configuration method of the present invention;

[0046] Figure 4 A schematic diagram of a VSG algorithm module of the energy storage converter system configuration method of the present invention;

[0047] Figure 5 A schematic diagram of a first voltage instruction generating module of the energy storage converter system configuration method of the present invention;

[0048] Figure 6 It is a schematic diagram of the energy storage converter system configuration method of the present invention. DETAILED DESCRIPTION

[0049] Energy Storage Converter

[0050] The power storage converter (PCS) can control the charging and discharging process of the battery, perform AC-DC conversion, and directly supply power to AC loads in the absence of a power grid. The traditional PCS can integrate the parallel energy storage system into the energy storage power station or power grid (new energy grid connection). The parallel energy storage system is connected to the collection device. The control system outputs a control signal to the parallel energy storage system to adjust the output voltage or output current based on the relevant operating parameters of the energy storage system collected by the collection device. However, in the traditional parallel method, each energy storage converter is independently connected to the grid and has an independent current loop, phase-locked loop and power control loop. When too many parallel connections are connected, circulating current and resonance problems are prone to occur. Figure 1 As shown, the energy storage converter system configuration method in the prior art adopts a parallel energy storage system converter control method to solve the circulation and resonance problems.

[0051] Virtual Synchronous Generator

[0052] VSG (Virtual Synchronous Generator) technology is a power system control method based on power control. It monitors the system frequency and voltage changes and adjusts the output power of the new energy system (such as photovoltaic power generation system) in real time to keep it synchronized with the power grid. VSG introduces the rotor motion equation into the inverter control algorithm, controls the energy storage device to absorb and release energy, simulates the mechanical energy in the synchronous generator rotor, and enables the inverter to have the anti-interference characteristics of the synchronous generator when dealing with disturbances, which can effectively improve the inertia and damping level of the system.

[0053] However, there is no report in the prior art on how to combine the control method of the parallel energy storage system converter with the VSG. The related technology simply integrates the two, but the external anti-interference characteristics of the VSG are significantly reduced.

[0054] In order to solve the above technical problems, various aspects of the present invention provide a method for configuring an energy storage converter system. The following describes the implementation of the present invention in detail with reference to the accompanying drawings and embodiments.

[0055] The specific technical solution of the present invention is as follows: A method for configuring an energy storage converter system, such as Figure 2 and Figure 6 As shown, including:

[0056] S1: Collect the converter current I output by PCS pcs and converter voltage Upcs , grid-side current I abc and grid voltage U abc , and the inductance value L of the power components in the PCS, according to the converter current I pcs and converter voltage U pcs , grid-side current I abc and grid voltage U abc and the inductance value L of the power element in the PCS outputs a first voltage command and a second voltage command;

[0057] S2: Based on the collected grid-side current I abc and grid voltage U abc , calculate the instantaneous active power value P and the instantaneous reactive power value Q;

[0058] S3: According to the grid side voltage U abc , Active power reference value P ref and reactive power reference value Q ref , instantaneous active power value P and instantaneous reactive power value Q, output voltage amplitude E and power angle δ;

[0059] S4: Outputting an SPWM instruction according to the second voltage instruction, the first voltage instruction, the voltage amplitude E and the power angle δ;

[0060] S5: Control PCS according to SPWM instructions.

[0061] In some specific embodiments, Figure 3 and Figure 5 As shown, the step of outputting the first voltage instruction in S1 specifically includes:

[0062] According to the grid voltage U abc And the grid-side current I abc Calculate output power;

[0063] According to the converter current I pcs , calculate the active current I 有功 ; where I 有功 refers to the active current,

[0064] According to the preset reference power and output power, the active current command is obtained through PI control of the active current command calculation module;

[0065] According to the active current command and active current I 有功 , the first voltage instruction is obtained through PI control of the first voltage instruction calculation module.

[0066] In some specific embodiments, Figure 3 As shown, the step of outputting the second voltage instruction in S1 specifically includes:

[0067] Receive converter current I pcs , calculate the reactive current I 无功 ;

[0068] Calculate the inductance difference according to the inductance value L of the power component in the PCS and the preset standard inductance;

[0069] According to the grid-side current I abc and grid voltage U abc , calculate the phase of the grid voltage and the amplitude of the grid voltage;

[0070] According to the reactive current I 无功 , calculate the voltage reference value U 参考 and current reference value I 参考 ;

[0071] According to the reactive current I 无功 , voltage reference value U 参考 and current reference value I 参考 As well as the phase and amplitude and the inductance value L of the power component in the PCS, the compensation voltage U is calculated through the compensation voltage algorithm 补偿 ;

[0072] According to the voltage reference value U 参考 And compensation voltage U 补偿 , the voltage reference value U 参考 And the compensation voltage U 补偿 The second voltage command is obtained by adding them together and the second voltage command is output.

[0073] In some specific embodiments, the compensation voltage algorithm includes an XYZ algorithm, which is:

[0074] Inductance difference × reactive current I 无功 ×k=compensation voltage U 补偿

[0075]

[0076] In some specific embodiments, Figure 2 and Figure 4 As shown, S3 is based on the grid-side voltage U abc , Active power reference value P ref and reactive power reference value Q ref , instantaneous active power value P and instantaneous reactive power value Q, output voltage amplitude E and power angle δ, including:

[0077] According to the active power reference value P ref and the angular velocity reference value ω 0 , instantaneous active power value P and grid-side voltage angular velocity ω g , calculate the active power compensation value P m ;

[0078] According to the active power compensation value P m And reactive power reference value Q ref and grid voltage U abc , the output voltage amplitude E and power angle δ are calculated by VSG algorithm.

[0079] In some specific embodiments, Figure 4 As shown, the VSG algorithm includes the following steps:

[0080] According to the active power compensation value P m , calculate the compensation angular velocity ω through the rotor motion equation;

[0081] According to the compensation angular velocity ω, the output power angle δ;

[0082] According to the reactive power reference value Q ref and grid voltage U abc , calculated by the excitation equation, the output voltage amplitude E.

[0083] It should be noted that the rotor motion equation of the present invention is a known technology, and equation (1) is an exemplary description:

[0084]

[0085] In formula (1), P D , P m and P c are the damping power, mechanical power and electromagnetic power of the synchronous generator respectively; J is the moment of inertia; D is the damping coefficient; ω 0 is the synchronous angular velocity of the power grid, and ω is the mechanical angular velocity of the synchronous generator.

[0086] It should be noted that the excitation equation of the present invention is a known technology, and equation (2) is an exemplary description:

[0087]

[0088] In formula (2), L is the synchronous reactance, r is the armature resistance, e is abc is the internal potential of VSG, u abc is the terminal voltage of VSG, i abc is the output current of VSG.

[0089] e abc =E[sinθsin(θ-2π / 3)sin(θ+2π / 3)] (3)

[0090] θ is the phase of VSG, θ=∫ωdt; E is the internal potential amplitude.

[0091] The above-described embodiments are merely descriptions of preferred implementation modes of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for configuring an energy storage converter system, characterized in that: include: S1: respectively collecting the converter current and converter voltage, the grid-side current and grid-side voltage, and the inductance value of the power element in the PCS output by the PCS, and outputting the first voltage instruction and the second voltage instruction according to the converter current and converter voltage, the grid-side current and grid-side voltage, and the inductance value of the power element in the PCS; S2: Calculating the instantaneous active power value and the instantaneous reactive power value according to the collected grid-side current and grid-side voltage; S3: outputting voltage amplitude and power angle according to the grid-side voltage, the active power reference value and the reactive power reference value, the instantaneous active power value and the instantaneous reactive power value; S4: Outputting an SPWM instruction according to the second voltage instruction, the first voltage instruction, the voltage amplitude and the power angle; S5: Control the PCS according to the SPWM instruction.

2. The energy storage converter system configuration method according to claim 1, characterized in that: The step of outputting the first voltage instruction in S1 specifically includes: Calculating output power according to the grid-side voltage and the grid-side current; calculating an active current component of the converter current; According to the preset reference power and the output power, an active current instruction is obtained through PI control; The first voltage instruction is obtained through PI control according to the active current instruction and the active current.

3. The energy storage converter system configuration method according to claim 2, characterized in that: The step of outputting the second voltage instruction in S1 specifically includes: calculating a reactive current component of the converter current; Calculating the phase of the grid voltage and the amplitude of the grid voltage according to the grid-side current and the grid-side voltage; Calculating a voltage reference value and a current reference value according to a reactive current component of the converter current; Calculating an inductance difference according to the inductance value of the power element in the PCS and a preset standard inductance; Calculating a compensation voltage by a compensation voltage algorithm according to the reactive current, the voltage reference value, the current reference value and the inductance difference value, the phase and the amplitude value, and the inductance value of the power element in the PCS; According to the voltage reference value and the compensation voltage, the voltage reference value and the compensation voltage are added to obtain the second voltage instruction, and the second voltage instruction is output.

4. The energy storage converter system configuration method according to claim 3, characterized in that: The compensation voltage algorithm includes an XYZ algorithm, and the XYZ algorithm is: Inductance difference × reactive current × k = compensation voltage in, 5. The energy storage converter system configuration method according to claim 1, characterized in that: The output voltage amplitude and power angle of S3 according to the grid-side voltage, the active power reference value, the reactive power reference value, the instantaneous active power value and the instantaneous reactive power value include: Calculating an active power compensation value according to the active power reference value and the angular velocity reference value, the instantaneous active power value and the grid-side voltage angular velocity; According to the active power compensation value, the reactive power reference value and the grid-side voltage, the voltage amplitude and the power angle are output through calculation by the VSG algorithm.

6. A method for configuring an energy storage converter system according to claim 5, characterized in that: The VSG algorithm comprises the following steps: Calculating the compensation angular velocity through the rotor motion equation according to the active power compensation value; Outputting a power angle according to the compensation angular velocity; The output voltage amplitude is calculated according to the reactive power reference value and the grid-side voltage through the excitation equation.

7. The energy storage converter system configuration method according to claim 5, characterized in that: The rotor motion equation is: In formula (1), P D , P m and P c are the damping power, mechanical power and electromagnetic power of the synchronous generator respectively; J is the moment of inertia; D is the damping coefficient; ω0 is the synchronous angular velocity of the power grid, and ω is the mechanical angular velocity of the synchronous generator.

8. The energy storage converter system configuration method according to claim 5, characterized in that: The excitation equation is: In formula (2), L is the synchronous reactance, r is the armature resistance, e is abc is the internal potential of VSG, u abc is the terminal voltage of VSG, i abc is the output current of VSG. e abc =E[sinθsin(θ-2π / 3)sin(θ+2π / 3)] (3) θ is the phase of VSG, θ=∫ωdt; E is the internal potential amplitude.

9. A system, characterized in that: The system comprises at least one processor; and a memory storing instructions, which, when executed by the at least one processor, implement the steps of the method according to any one of claims 1 to 8.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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