Industrial and commercial energy storage PCS power control method

Abstract

The invention provides an industrial and commercial energy storage PCS power control method in the technical field of energy storage converters. The industrial and commercial energy storage PCS power control method comprises the steps that S1, an active power instruction PRef, a reactive power instruction QRef, a three-phase load current ILabc, a three-phase control current ILabc, a three-phase power grid voltage Ugabc and a direct-current bus voltage Udc are obtained; s2, calculating a d-axis component Ugd of the power grid voltage, a q-axis component Ugq of the power grid voltage and a power grid angle theta g; calculating a control current positive sequence d-axis component ICPd, a control current positive sequence q-axis component ICPq, a control current negative sequence d-axis component ICNd, a control current negative sequence q-axis component ICNq and a control current zero sequence component IC0; a step S3 of calculating ILNd, ILNq, IL0, IRRefPd, IRRefPq, IRRefNd, IRRefNq and IRRef0; a step S3 of calculating ILNd, ILNq, IL0, IRRefPd, IRRefPq, IRRefNd, IRRefNq and IRRef0; and S4, carrying out closed-loop control on the IRFPd, the IRFPq, the IRFNd, the IRFNq and the IRF0 to obtain SPWM (sinusoidal pulse width modulation), and controlling a three-phase bridge arm of the PCS based on the SPWM. The method has the advantages that the influence of load imbalance on a distribution transformer and a power grid is greatly reduced while conventional power scheduling is met.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage converters, and in particular to a power control method for industrial and commercial energy storage PCSs. Background Art

[0002] Industrial and commercial energy storage is a modern energy storage technology designed to provide a reliable and efficient energy storage and supply system for the industrial and commercial sectors. With the development of the global economy and the increase in energy consumption, industrial and commercial energy storage is becoming an effective means of addressing energy supply shortages and energy volatility. Industrial and commercial energy storage systems play a vital role in the new power grid, including energy storage and balancing, frequency and phase regulation, load smoothing and scheduling, emergency backup power, and intelligent monitoring and management. They provide critical support for the efficient and stable operation of the new power grid and can address the issue of insufficient access capacity for basic distribution networks.

[0003] In response to the power control problem of energy storage systems, patent CN118281922A discloses a power control method for energy storage power stations. By obtaining the latest N power data at the current time, a control decision model is constructed to prevent overload and backflow. A dynamic deviation mechanism is constructed to correct the control decision simulation to obtain execution power data. This can avoid the problem of unsatisfactory overload and backflow prevention effects of energy storage power stations or repeated power fluctuations of energy storage equipment under critical conditions; patent CN118763711A discloses a power control method for virtual power plant energy storage parallel system. By collecting the total power demand data of the power grid and the status parameters of each energy storage unit, the maximum charge and discharge power capacity coefficient is calculated. According to the total power demand data and status parameters, combined with the battery health status coefficient and the maximum charge and discharge power capacity coefficient, power weight is allocated to obtain the corresponding command power data, thereby realizing power control of the virtual power plant energy storage parallel system.

[0004] Areas where industrial and commercial energy storage systems are installed are typically connected to the high-voltage grid via one or more distribution transformers. The low-voltage side of these distribution transformers inevitably connects to three-phase, four-wire loads, which inevitably creates three-phase current imbalance in the distribution transformers, impacting the grid. Therefore, developing a power control method for industrial and commercial energy storage systems (PCSs) that can meet conventional power dispatch requirements while minimizing the impact of load imbalance on the distribution transformers and the grid has become a pressing technical challenge. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an industrial and commercial energy storage PCS power control method to reduce the impact of load imbalance on distribution transformers and power grids while meeting conventional power scheduling.

[0006] The present invention is implemented as follows: A method for controlling power of an industrial and commercial energy storage PCS comprises the following steps:

[0007] Step S1: Receive active power instruction P Ref And reactive power command Q Ref , collect three-phase load current I Labc , three-phase control current I Cabc , three-phase grid voltage U gabc And the DC bus voltage U dc ;

[0008] Step S2: Based on the three-phase grid voltage U gabc Calculate the d-axis component of the grid voltage U gd , grid voltage q-axis component U gq and grid angle θ g Based on the three-phase control current I Cabc and the grid angle θ g Calculate the positive sequence d-axis component of the control current I CPd , control current positive sequence q-axis component I CPq , control current negative sequence d-axis component I CNd , control current negative sequence q-axis component I CNq and control current zero sequence component I C0 ;

[0009] Step S3: Based on the three-phase load current I Labc and the grid angle θ g Calculate the negative sequence d-axis component of the load current I LNd , load current negative sequence q-axis component I LNq and the load current zero sequence component I L0 ;

[0010] Step S4: Based on the active power instruction P Ref And reactive power command Q Ref Calculate the positive sequence d-axis component of the reference current I RefPd , reference current positive sequence q-axis component I RefPq ;

[0011] Step S5: Calculate the negative sequence d-axis component of the reference current I RefNd , reference current negative sequence q-axis component I RefNq and the reference current zero sequence component I Ref0 ;

[0012] Step S6: the positive sequence d-axis component I of the reference current RefPd , reference current positive sequence q-axis component I RefPq , reference current negative sequence d-axis component I RefNd , reference current negative sequence q-axis component I RefNq And the reference current zero sequence component I Ref0 Perform closed-loop control to obtain the output signal SPWM , based on the output signal S PWM Control the power output of the three-phase bridge arm of the PCS.

[0013] Furthermore, the step S4 is specifically as follows:

[0014] Based on the active power instruction P Ref And the grid voltage d-axis component U gd Calculate the first-level reference current positive sequence d-axis component I RefPd1 :

[0015] I RefPd1 =P Ref / U gd ;

[0016] Based on the reactive power instruction Q Ref And the grid voltage d-axis component U gd Calculate the positive sequence q-axis component of the reference current I RefPq :

[0017] I RefPq =Q Ref / U gd ;

[0018] In the DC voltage condition control link, the DC bus voltage U dc Perform conditional closed-loop control to obtain the second-level reference current positive sequence d-axis component I RefPd2 ;

[0019] Based on the first-level reference current positive sequence d-axis component I RefPd1 And the second-level reference current positive sequence d-axis component I RefPd2 Calculate the positive sequence d-axis component of the reference current I RefPd :

[0020] I RefPd =I RefPd1 +I RefPd2 .

[0021] Furthermore, the step S5 is specifically as follows:

[0022] Calculate the negative sequence current limit value I LIMN , according to the negative sequence current limit value I LIMN , load current negative sequence d-axis component I LNd , load current negative sequence q-axis component I LNq , calculate the reference current negative sequence d-axis component I RefNd And the reference current negative sequence q-axis component I RefNq ;

[0023] Calculate the zero-sequence current limit value I LIM0 , according to the zero-sequence current limit value ILIM0 And the load current zero sequence component I L0 Obtain the reference current zero sequence component I Ref0 .

[0024] The advantages of the present invention are:

[0025] By receiving the active power command P Ref And reactive power command Q Ref , collect three-phase load current I Labc , three-phase control current I Cabc , three-phase grid voltage U gabc And the DC bus voltage U dc ; Then based on the three-phase grid voltage U gabc Calculate the d-axis component of the grid voltage U gd , grid voltage q-axis component U gq and grid angle θ g ; Based on three-phase control current I Cabc and the grid angle θ g Calculate the positive sequence d-axis component of the control current I CPd , control current positive sequence q-axis component I CPq , control current negative sequence d-axis component I CNd , control current negative sequence q-axis component I CNq and control current zero sequence component I C0 ; Based on the three-phase load current I Labc and the grid angle θ g Calculate the negative sequence d-axis component of the load current I LNd , load current negative sequence q-axis component I LNq and the load current zero sequence component I L0 ; Based on active power instruction P Ref And reactive power command Q Ref Calculate the positive sequence d-axis component of the reference current I RefPd , reference current positive sequence q-axis component I RefPq ; Calculate the negative sequence d-axis component of the reference current I RefNd , reference current negative sequence q-axis component I RefNq and the reference current zero sequence component I Ref0 ; Finally, the reference current positive sequence d-axis component I RefPd , reference current positive sequence q-axis component I RefPq , reference current negative sequence d-axis component I RefNd , reference current negative sequence q-axis component I RefNq And the reference current zero sequence component I Ref0 Perform closed-loop control to obtain the output signal S PWM , based on the output signal S PWMControl the power output of the three-phase bridge arm of the PCS; that is, on the basis of meeting the basic power control and dispatch of industrial and commercial energy storage systems, by collecting the three-phase load current I Labc , extract the three-phase load current I Labc The negative sequence component (negative sequence d axis component I LNd , negative sequence q-axis component I LNq ) and zero sequence component I L0 On the premise of ensuring that the PCS current is not overloaded, the current potential of the PCS is fully tapped to compensate for the unbalanced current of the load to the maximum extent, so as to reduce the amount of unbalanced current of the load flowing into the power grid through the distribution transformer. At the same time, it can also improve the economic efficiency of the operation of the distribution transformer. Ultimately, while meeting the conventional power dispatch, the impact of load imbalance on the distribution transformer and the power grid is greatly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Figure 1 This is a flow chart of a power control method for industrial and commercial energy storage PCS according to the present invention.

[0028] Figure 2 It is the electrical principle block diagram of the industrial and commercial energy storage system of the present invention.

[0029] Figure 3 This is the electrical principle block diagram of the energy storage system PCS of the present invention.

[0030] Figure 4 It is a flow chart of the signal transmission of the phase-locked loop and coordinate transformation link of the present invention.

[0031] Figure 5 It is a flow chart of the transmission of the calculation signal of the positive sequence dq axis component of the reference current of the present invention.

[0032] Figure 6 It is a flow chart of the transmission of calculation signals of negative sequence dq axis components and zero sequence components of reference current of the present invention. DETAILED DESCRIPTION

[0033] The technical solution in the embodiment of the present application has the following general idea: according to the received EMS power instruction (active power instruction P Ref And reactive power command Q Ref ) and DC bus voltage U dc Obtain the positive sequence dq axis component of the reference current (positive sequence d axis component I RefPd , positive sequence q-axis component I RefPq ), according to the collected three-phase load current I Labc Obtain the negative sequence dq axis component of the load current (negative sequence d axis component I LNd , negative sequence q-axis component ILNq ) and zero sequence component I L0 The maximum output current is subtracted from the reference current positive sequence apparent value to obtain the negative sequence current limit value, and the negative sequence dq axis component of the load current is limited by the negative sequence current limit value to obtain the reference current negative sequence dq axis component; the negative sequence current limit value is subtracted from the reference current negative sequence apparent value to obtain the zero sequence current limit value, and the zero sequence component of the load current is limited by the zero sequence current limit value to obtain the reference current zero sequence component; the reference current positive sequence dq axis component, the reference current negative sequence dq axis component and the reference current zero sequence component are closed-loop controlled respectively, and a PWM signal is output (output signal S PWM ) to the three-phase bridge arm to achieve the required power output.

[0034] Please refer to Figures 1 to 6 As shown in the figure, the area where industrial and commercial energy storage is configured is connected to the high-voltage power grid through a distribution transformer. The energy storage system mainly consists of three parts: batteries, energy storage converters (PCS), and energy management systems (EMS). The energy storage system is connected to the low-voltage side of the distribution network through the PCS. The PCS receives the active power command P issued by the EMS. Ref and reactive power command Q Ref , collect the three-phase load current I through the current transformer CT Labc .

[0035] The PCS consists of two parts: the main circuit and the control unit. The main circuit is mainly composed of three bridge arms: phase A, phase B and phase C, which are composed of power electronic devices. The power control method is implemented in the control unit. The control unit collects the three-phase grid voltage U from the main circuit. gabc , three-phase control current I Cabc and DC bus voltage U dc , output PWM modulation signal S PWM To the three bridge arms of the main circuit.

[0036] In order to facilitate understanding of the present invention, the meanings of the characters in the present invention are uniformly explained:

[0037] P Ref : Active power command;

[0038] Q Ref : Reactive power command;

[0039] I Labc : three-phase load current;

[0040] I Cabc : Three-phase control current;

[0041] U gabc : three-phase grid voltage;

[0042] U dc : DC bus voltage;

[0043] U gd : d-axis component of grid voltage;

[0044] U gq : q-axis component of grid voltage;

[0045] θ g : grid angle;

[0046] I CPd : Control current positive sequence d-axis component;

[0047] I CPq : Control current positive sequence q-axis component;

[0048] I CNd : negative sequence d-axis component of control current;

[0049] I CNq : negative sequence q-axis component of control current;

[0050] I C0 : Control current zero sequence component;

[0051] I LNd : negative sequence d-axis component of load current;

[0052] I LNq : negative sequence q-axis component of load current;

[0053] I L0 : zero-sequence component of load current;

[0054] I RefPd : positive sequence d-axis component of reference current;

[0055] I RefPq : positive sequence q-axis component of reference current;

[0056] I RefNd : negative sequence d-axis component of reference current;

[0057] I RefNq : negative sequence q-axis component of reference current;

[0058] I Ref0 : Zero-sequence component of reference current.

[0059] A preferred embodiment of a power control method for an industrial and commercial energy storage PCS of the present invention includes the following steps:

[0060] Step S1: Receive active power instruction P Ref And reactive power command Q Ref , collect three-phase load current I Labc , three-phase control current I Cabc , three-phase grid voltage U gabcAnd the DC bus voltage U dc ;

[0061] Step S2: Based on the three-phase grid voltage U gabc Calculate the d-axis component of the grid voltage U gd , grid voltage q-axis component U gq and grid angle θ g Based on the three-phase control current I Cabc and the grid angle θ g Calculate the positive sequence d-axis component of the control current I CPd , control current positive sequence q-axis component I CPq , control current negative sequence d-axis component I CNd , control current negative sequence q-axis component I CNq and control current zero sequence component I C0 ;

[0062] Step S3: Based on the three-phase load current I Labc and the grid angle θ g Calculate the negative sequence d-axis component of the load current I LNd , load current negative sequence q-axis component I LNq and the load current zero sequence component I L0 ;

[0063] Step S4: Based on the active power instruction P Ref And reactive power command Q Ref Calculate the positive sequence d-axis component of the reference current I RefPd , reference current positive sequence q-axis component I RefPq ;

[0064] Step S5: Calculate the negative sequence d-axis component of the reference current I RefNd , reference current negative sequence q-axis component I RefNq and the reference current zero sequence component I Ref0 ;

[0065] Step S6: the positive sequence d-axis component I of the reference current RefPd , reference current positive sequence q-axis component I RefPq , reference current negative sequence d-axis component I RefNd , reference current negative sequence q-axis component I RefNq And the reference current zero sequence component I Ref0 Perform closed-loop control to obtain the output signal S PWM , based on the output signal S PWM Control the power output of the three-phase bridge arm of the PCS.

[0066] The step S1 further includes: Ref , reactive power command Q Ref, three-phase load current I Labc , three-phase control current I Cabc , three-phase grid voltage U gabc And the DC bus voltage U dc Perform per-unit normalization and set the per-unit value to 1.0.

[0067] In step S2, the grid voltage d-axis component U gd , grid voltage q-axis component U gq and the grid angle θ g Calculated by a phase-locked loop (PLL); the phase-locked loop preferably adopts a synchronous rotating coordinate system phase-locked loop solution, the full name of which is Synchronous Reference Frame Phase Locked Loop, abbreviated as SRF-PLL;

[0068] The positive sequence d-axis component of the control current I CPd , control current positive sequence q-axis component I CPq , control current negative sequence d-axis component I CNd , control current negative sequence q-axis component I CNq And the control current zero sequence component I C0 Through the grid angle θ g It is obtained by performing synchronous rotation coordinate transformation calculation.

[0069] The control current coordinate transformation link includes two functions: positive and negative sequence decomposition and coordinate transformation. The positive and negative sequence decomposition function converts the input three-phase control current I Cabc Decomposed into positive sequence component, negative sequence component and zero sequence component, the coordinate transformation function is based on the input grid angle θ g Perform synchronous rotating coordinate transformation to transform the three-phase current with positive sequence component in ABC coordinate system into two-phase current in positive sequence dq synchronous rotating coordinate system, and transform the three-phase current with negative sequence component in ABC coordinate system into two-phase current in negative sequence dq synchronous rotating coordinate system; the zero sequence component is the algebraic sum of the three-phase control currents;

[0070] The effective value calculation step first calculates the three-phase control current I Cabc The three effective values are then compared, and the largest value is the maximum effective value of the three-phase current I CRmsMax ;

[0071] In step S3, the load current negative sequence d-axis component I LNd , load current negative sequence q-axis component I LNq And the load current zero sequence component I L0 Through the grid angle θ g It is obtained by performing synchronous rotation coordinate transformation calculation.

[0072] The load current coordinate transformation link also includes two functions: positive and negative sequence decomposition and coordinate transformation. The positive and negative sequence decomposition function converts the input three-phase load current I Labc Decomposed into positive sequence component, negative sequence component and zero sequence component, only the negative sequence component and zero sequence component are used; the coordinate transformation function is based on the input grid angle θ g Perform synchronous rotating coordinate transformation to transform the three-phase current with negative sequence component in ABC coordinate system into two-phase current in negative sequence dq synchronous rotating coordinate system; the zero sequence component is the algebraic sum of three-phase load current.

[0073] The step S4 is specifically as follows:

[0074] Based on the active power instruction P Ref And the grid voltage d-axis component U gd Calculate the first-level reference current positive sequence d-axis component I RefPd1 :

[0075] I RefPd1 =P Ref / U gd ;correspond Figure 5 Formula (1);

[0076] Based on the reactive power instruction Q Ref And the grid voltage d-axis component U gd Calculate the positive sequence q-axis component of the reference current I RefPq :

[0077] I RefPq =Q Ref / U gd ;correspond Figure 5 Formula (1);

[0078] In the DC voltage condition control link, the DC bus voltage U dc Perform conditional closed-loop control to obtain the second-level reference current positive sequence d-axis component I RefPd2 ;

[0079] Based on the first-level reference current positive sequence d-axis component I RefPd1 And the second-level reference current positive sequence d-axis component I RefPd2 Calculate the positive sequence dq axis component I RefPd :

[0080] I RefPd =I RefPd1 +I RefPd2 .

[0081] The second-stage reference current positive sequence d-axis component I RefPd2 The calculation formula is:

[0082] correspond Figure 5 Formula (2);

[0083] I RefPd2 =(K P1 +K I1 / S)(U dcErr -K C1 I RefPd2 );correspond Figure 5 Formula (3), that is, for U dcErr Perform PIC control;

[0084] Among them, U dcErr Indicates the DC voltage error, which is calculated based on the range of the DC bus voltage; U dcMin Indicates the minimum DC bus voltage; U dcMax Indicates the maximum DC bus voltage; K P1 Indicates the proportional coefficient of the PIC control link; K I1 Indicates the integral coefficient of the PIC control link; S represents the complex frequency variable; K C1 Indicates the anti-saturation coefficient of the PIC control link.

[0085] Through DC voltage condition control, the DC bus voltage can be controlled within [U dcMin ,U dcMax ] range, respond to EMS power dispatch instructions, and when the battery is about to be discharged or fully charged, RefPd2 The function is to maintain the DC bus voltage within the range where the PCS can operate normally.

[0086] The step S5 is specifically as follows:

[0087] Considering the impact of the phase relationship between the positive-sequence current and the negative-sequence current on the maximum phase current amplitude, when the two are in phase, the maximum phase current amplitude is the sum of the positive-sequence current and the negative-sequence current. When the phase difference between the two is 60°, the sum of the positive-sequence current and the negative-sequence current will reach 1.155 times the maximum phase current. Based on this feature, the PCS output current capacity is modified to fully tap the PCS output capacity for unbalanced current while ensuring that the phase current does not exceed the rated current, including the reference current negative-sequence dq-axis component I RefNd , I RefNq Calculation and reference current zero sequence component I Ref0 The calculation consists of two parts.

[0088] Calculate the negative sequence current limit value I LIMN , according to the negative sequence current limit value I LIMN , load current negative sequence d-axis component I LNd , load current negative sequence q-axis component I LNq , calculate the reference current negative sequence d-axis component IRefNd And the reference current negative sequence q-axis component I RefNq ;

[0089] Taking the per-unit value 1.0 as reference, the maximum effective value of the three-phase current I calculated in step S2 is CRmsMax As feedback, PI closed-loop control is performed to output the rated current correction deviation value I LIMD , I LIMD ∈(0, 0.155), such as Figure 6 As shown; calculate the reference current positive sequence apparent value I RefP ; The current standard value 1.0 plus the rated current correction deviation value I LIMD , minus the apparent value of the reference current positive sequence I RefP , and obtain the negative sequence current limit value I LIMN , I LIMN ∈(0, 1.0), such as Figure 6 shown; among them,

[0090] Calculate the apparent negative sequence value of the load current I LN ; Calculate the negative sequence current limit value I LIMN and the apparent negative sequence value of the load current I LN The ratio K2, K2∈(0,1.0), such as Figure 6 shown; among them, Then calculate the negative sequence d-axis component of the reference current I RefNd and the reference current negative sequence q-axis component I RefNq :

[0091]

[0092] Calculate the zero-sequence current limit value I LIM0 , according to the zero-sequence current limit value I LIM0 And the load current zero sequence component I L0 Obtain the zero sequence component I Ref0 .

[0093] Calculate the reference current negative sequence apparent value I RefN ; Negative sequence current limit value I LIMN Subtract the reference current negative sequence apparent value I RefN Get the zero-sequence current limit value I LIM0 , I LIM0 ∈(0, 0.2), such as Figure 6 shown; among them, Then calculate the reference current zero sequence component I Ref0 :

[0094]

[0095] The step S6 is specifically as follows:

[0096] Taking the positive sequence d-axis component of the reference current I RefPd , reference current positive sequence q-axis component I RefPq , reference current negative sequence d-axis component I RefNd , reference current negative sequence q-axis component I RefNq , reference current zero sequence component I Ref0 As a reference, to control the positive sequence d-axis component of the current I CPd , control current positive sequence q-axis component I CPq , control current negative sequence d-axis component I CNd , control current negative sequence q-axis component I CNq , control current zero sequence component I C0 For feedback, each current is independently controlled through five current loops and the output PWM signal S PWM To the three-phase bridge arm, the required power output is completed.

[0097] In summary, the advantages of the present invention are:

[0098] By receiving the active power command P Ref And reactive power command Q Ref , collect three-phase load current I Labc , three-phase control current I Cabc , three-phase grid voltage U gabc And the DC bus voltage U dc ; Then based on the three-phase grid voltage U gabc Calculate the d-axis component of the grid voltage U gd , grid voltage q-axis component U gq and grid angle θ g ; Based on three-phase control current I Cabc and the grid angle θ g Calculate the positive sequence d-axis component of the control current I CPd , control current positive sequence q-axis component I CPq , control current negative sequence d-axis component I CNd , control current negative sequence q-axis component I CNq and control current zero sequence component I C0 ; Based on the three-phase load current I Labc and the grid angle θ g Calculate the negative sequence d-axis component of the load current I LNd , load current negative sequence q-axis component I LNq and the load current zero sequence component I L0 ; Based on active power instruction P Ref And reactive power command Q Ref Calculate the positive sequence d-axis component of the reference current I RefPd , reference current positive sequence q-axis component IRefPq ; Calculate the negative sequence d-axis component of the reference current I RefNd , reference current negative sequence q-axis component I RefNq and the reference current zero sequence component I Ref0 ; Finally, the reference current positive sequence d-axis component I RefPd , reference current positive sequence q-axis component I RefPq , reference current negative sequence d-axis component I RefNd , reference current negative sequence q-axis component I RefNq And the reference current zero sequence component I Ref0 Perform closed-loop control to obtain the output signal S PWM , based on the output signal S PWM Control the power output of the three-phase bridge arm of the PCS; that is, on the basis of meeting the basic power control and dispatch of industrial and commercial energy storage systems, by collecting the three-phase load current I Labc , extract the three-phase load current I Labc The negative sequence component (negative sequence d axis component I LNd , negative sequence q-axis component I LNq ) and zero sequence component I L0 On the premise of ensuring that the PCS current is not overloaded, the current potential of the PCS is fully tapped to compensate for the unbalanced current of the load to the maximum extent, so as to reduce the amount of unbalanced current of the load flowing into the power grid through the distribution transformer. At the same time, it can also improve the economic efficiency of the operation of the distribution transformer. Ultimately, while meeting the conventional power dispatch, the impact of load imbalance on the distribution transformer and the power grid is greatly reduced.

[0099] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A power control method for industrial and commercial energy storage PCS, characterized by: The steps include: Step S1: Receive active power instruction P Ref And reactive power command Q Ref , collect three-phase load current I Labc , three-phase control current I Cabc , three-phase grid voltage U gabc And the DC bus voltage U dc ; Step S2: Based on the three-phase grid voltage U gabc Calculate the d-axis component of the grid voltage U gd , grid voltage q-axis component U gq and grid angle θ g Based on the three-phase control current I Cabc and the grid angle θ g Calculate the positive sequence d-axis component of the control current I CPd , control current positive sequence q-axis component I CPq , control current negative sequence d-axis component I CNd , control current negative sequence q-axis component I CNq and control current zero sequence component I C0 ; Step S3: Based on the three-phase load current I Labc and the grid angle θ g Calculate the negative sequence d-axis component of the load current I LNd , load current negative sequence q-axis component I LNq and the load current zero sequence component I L0 ; Step S4: Based on the active power instruction P Ref And reactive power command Q Ref Calculate the positive sequence d-axis component of the reference current I RefPd , reference current positive sequence q-axis component I RefPq ; Step S5: Calculate the negative sequence d-axis component of the reference current I RefNd , reference current negative sequence q-axis component I RefNq and the reference current zero sequence component I Ref0 ; Step S6: the positive sequence d-axis component I of the reference current RefPd , reference current positive sequence q-axis component I RefPq , reference current negative sequence d-axis component I RefNd , reference current negative sequence q-axis component I RefNq And the reference current zero sequence component I Ref0 Perform closed-loop control to obtain the output signal S PWM , based on the output signal S PWM Control the power output of the three-phase bridge arm of the PCS.

2. The industrial and commercial energy storage PCS power control method according to claim 1, characterized in that: The step S4 is specifically as follows: Based on the active power instruction P Ref And the grid voltage d-axis component U gd Calculate the first-level reference current positive sequence d-axis component I RefPd1 : AND RefPd1 =P Ref / IN gd ; Based on the reactive power instruction Q Ref And the grid voltage d-axis component U gd Calculate the positive sequence q-axis component of the reference current I RefPq : I RefPq =Q Ref / U gd ; In the DC voltage condition control link, the DC bus voltage U dc Perform conditional closed-loop control to obtain the second-level reference current positive sequence d-axis component I RefPd2 ; Based on the first-level reference current positive sequence d-axis component I RefPd1 And the second-level reference current positive sequence d-axis component I RefPd2 Calculate the positive sequence d-axis component of the reference current I RefPd : I RefPd =I RefPd1 +I RefPd2 。 3. The industrial and commercial energy storage PCS power control method according to claim 1, characterized in that: The step S5 is specifically as follows: Calculate the negative sequence current limit value I LIMN , according to the negative sequence current limit value I LIMN , load current negative sequence d-axis component I LNd , load current negative sequence q-axis component I LNq , calculate the reference current negative sequence d-axis component I RefNd And the reference current negative sequence q-axis component I RefNq ; Calculate the zero-sequence current limit value I LIM0 , according to the zero-sequence current limit value I LIM0 And the load current zero sequence component I L0 Obtain the reference current zero sequence component I Ref0 .

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