CN110086169B - Power distribution network control method - Google Patents

Abstract

The application relates to a power distribution network control method, which is used for respectively controlling converters on two sides of an SOP module and comprises the following steps: according to the active current target value and the reactive current target value of the converter, obtaining a three-phase current target value of the converter; compensating the three-phase current target value of the converter according to the actual value of the three-phase current at the load side to obtain the final target value of the three-phase current of the converter; and controlling the on-off of a switching tube of the converter according to the difference value between the final target value of the three-phase current of the converter and the actual value of the three-phase current of the converter. The method and the device can compensate the unbalanced load currents on two sides of the SOP module respectively, so that the three-phase voltages of the power grids on two sides of the SOP module tend to be balanced respectively.

Description

A distribution network control method

technical field

The invention relates to the field of power systems, in particular to a distribution network control method.

Background technique

At present, the intelligent soft switch SOP (Soft Open Point) technology for power distribution level is triggering a new round of research upsurge. The SOP technology aims to replace the traditional circuit breaker-based feeder tie switch with a controllable power electronic converter, so as to realize the normalized flexible "soft connection" between feeders, and provide flexible, fast and accurate power exchange control and power flow optimization capabilities.

The basic structure of SOP can be described by a back-to-back AC/DC/AC converter composed of high-power fully-controlled power electronic components (such as insulated gate bipolar transistors, IGBTs, etc.). Figure 1 shows a typical SOP structure. Among them, VSC1 and VSC2 are voltage source converters. Generally speaking, the converters on both sides of the SOP are completely symmetrical in structure. By implementing appropriate control strategies, the two-way flexible flow and precise control of power can be realized in accordance with dispatching instructions. After the SOP is used to replace the tie switch in the distribution network, the power flow distribution of the entire system can be affected or changed by controlling the power exchange of the feeders on both sides, making the operation scheduling of the distribution network more "flexible".

Figure 2 shows a typical application of a distribution network in which traditional tie switches are replaced by SOP. Compared with the conventional network connection method based on tie switches, SOP realizes the normalized flexible interconnection between feeders and avoids safety hazards caused by frequent displacement of switches. It greatly improves the flexibility and rapidity of distribution network control, and enables the distribution network to have the advantages of both open-loop and closed-loop operation.

Because the load in the distribution network is difficult to achieve balance, the voltage on both sides of the SOP is unbalanced. The current solution is to control the DC bus voltage stability through the converter on one side of the SOP module, and transform it through the other side of the SOP module. The device controls the flowing active power to realize the approach adjustment of the voltage on both sides of the SOP module, that is, the three-phase voltage on one side is synchronously reduced, and the three-phase voltage on the other side is synchronously increased, so that the voltage on both sides tends to be the same. However, this control strategy can only increase or decrease the three-phase voltage on both sides synchronously, and the imbalance between the three-phase voltages on each side has not been controlled. The unbalanced three-phase voltage will increase the power loss of the line, increase the power loss of the distribution transformer, and affect the safe operation of the electrical equipment.

Therefore, under the premise of satisfying the voltage balance on both sides of the SOP module, realizing the balance between the three-phase voltages is an urgent problem to be solved at present.

Contents of the invention

The invention proposes a distribution network control method, which solves the problem of imbalance between the three-phase voltages on one side of the SOP module in the prior art.

Technical scheme of the present invention is realized like this:

A distribution network control method, the distribution network includes a SOP module, wherein a converter on one side of the SOP module is configured to control the flow of active power, and a converter on the other side of the SOP module is configured to control a DC bus voltage, respectively. The converters on both sides of the module are controlled, including:

According to the active current target value and the reactive current target value of the converter, the three-phase current target value of the converter is obtained;

Compensate the target value of the three-phase current of the converter according to the actual value of the three-phase current on the load side to obtain the final target value of the three-phase current of the converter;

According to the difference between the final target value of the three-phase current of the converter and the actual value of the three-phase current of the converter, the on-off of the switch tube of the converter is controlled.

Optionally, for a converter configured to control the flow of active power, the target value of active current of the converter is obtained according to the difference between the target value of active power flowing through the converter and the actual value of active power.

Optionally, for the one-side converter configured to control the DC bus voltage, the target active current value of the converter is obtained according to the difference between the target value of the DC bus voltage and the actual value of the DC bus voltage.

Optionally, the reactive current target value of the converter is obtained according to the difference between the converter output reactive power target value and the reactive power actual value.

Optionally, the obtaining the three-phase current target value of the converter according to the active current target value and the reactive current target value of the converter includes:

According to the phase information of the three-phase voltage of the power grid, the active current target value and the reactive current target value of the converter are transformed from the dq axis to the abc axis, and the three-phase current target value of the converter is obtained.

Optionally, the compensating the target value of the three-phase current of the converter according to the actual value of the three-phase current at the load side to obtain the final target value of the three-phase current of the converter includes:

According to the phase information of the three-phase voltage of the power grid, the actual value of the three-phase current on the load side is transformed from the abc axis to the dq axis, and then through low-pass filtering and PI adjustment, the dq axis components of the compensation current that the converter needs to provide are obtained;

According to the phase information of the three-phase voltage of the power grid, the dq-axis component of the compensation current is transformed from the dq axis to the abc axis to obtain the three-phase compensation current value;

According to the three-phase compensation current value and the target value of the three-phase current of the converter, the final target value of the three-phase current of the converter is obtained.

Optionally, the transformation of the actual value of the three-phase current on the load side from the abc axis to the dq axis according to the phase information of the three-phase voltage of the power grid includes: after inverting the phase information of the three-phase voltage of the power grid, as the three-phase load side The current actual value is transformed from the abc axis to the phase information of the dq axis.

Optionally, the coordinate transformation from the dq axis to the abc axis of the dq axis component of the compensation current according to the phase information of the three-phase voltage of the power grid includes: after inverting the phase information of the three-phase voltage of the power grid, as the dq of the compensation current The axis component is transformed from the dq axis to the phase information of the abc axis.

Optionally, the phase information of the three-phase voltage of the power grid is obtained by extracting a positive sequence component of the power grid voltage, and obtaining it after being phase-locked by a phase-locked loop.

Optionally, the controlling the on-off of the switch tube of the converter according to the difference between the final target value of the three-phase current of the converter and the actual value of the three-phase current of the converter includes: combining the final target value of the three-phase current of the converter with the actual value of the three-phase current of the converter The difference between the actual values of the three-phase currents is controlled by hysteresis, and the comparison result is converted into a gate signal of the switch tube of the converter to control the on-off of the switch tube.

The beneficial effects of the present invention are:

(1) Compensate the load current unbalance on both sides of the SOP module respectively, and obtain the final target value of the three-phase current of the converter on both sides, so that the three-phase current of the power grid on both sides of the SOP module tends to balance, and then makes the three-phase current of the power grid on both sides of the SOP module tend to be balanced. The phase voltages tend to be balanced respectively.

(2) Ensure the stability of the power grid and improve the quality of power supply.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

Figure 1 is a schematic diagram of a typical SOP structure;

Figure 2 is a schematic structural diagram of a distribution network using SOP;

Fig. 3 is a schematic diagram of an optional implementation structure of the distribution network;

FIG. 4 is a schematic flowchart of a distribution network control method provided by an embodiment of the present disclosure;

FIG. 5 is a functional block diagram of a distribution network control method provided by an embodiment of the present disclosure;

FIG. 6 is a functional block diagram of a distribution network control method provided by an embodiment of the present disclosure;

Fig. 7 is a functional block diagram of a distribution network control system provided by an embodiment of the present disclosure.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Figure 3 shows an alternative implementation structure of the distribution network.

V _1a , V _1b , V _1c are the three-phase voltages of the power grid on one side connected to the SOP module converter VSC1, i _s1,a , i _s1,b , and i _s1,c are the three-phase currents of the converter VSC1, V _2a , V _2b , V _2c are the three-phase voltages of the power grid on the other side connected to the SOP module converter VSC2, i _s2,a , i _s2,b , and i _s2,c are the three-phase currents of the converter VSC2, and the VSC controller outputs The gate signal is sent to VSC1 and VSC2 to control the on-off of the switch tube. Install current sensors on the load side Load1 and Load2 of the grid respectively, and measure the actual value of the three-phase current on the load side i _l1,a , i _l1,b , i _l1,c and i _l2,a , i _l2,b , i _l2,c .

In the embodiment of the present disclosure, the converter VSC1 on one side of the SOP module is configured to control the flow of active power, and the converter VSC2 on the other side of the SOP module is configured to control the DC bus voltage. Of course, in other embodiments, the SOP The converter VSC2 of the module is configured to control the flow of active power, and the converter VSC1 on the other side of the SOP module is configured to control the DC bus voltage.

Figure 4 shows an alternative embodiment of a distribution network control method.

The embodiment of the present disclosure provides a distribution network control method, which respectively controls the converters VSC1 and VSC2 on both sides of the SOP module, including: according to the active current target value and reactive current target value of the converter, obtain the converter three Phase current target value; according to the actual value of the load side three-phase current, the converter three-phase current target value is compensated to obtain the final target value of the converter three-phase current; according to the final target value of the converter three-phase current and the converter three-phase current actual The difference between the values controls the on-off of the switch tube of the converter.

Using the above-mentioned embodiment, the load current imbalance on both sides of the SOP module is compensated respectively, and the final target value of the output three-phase current of the converters on both sides is obtained, so that the three-phase current of the power grid on both sides of the SOP module tends to balance, and then makes the two sides of the SOP module The three-phase voltages of the power grid tend to be balanced respectively, ensuring the stability of the power grid and improving the quality of power supply.

Optionally, for the converter on one side configured to control the flow of active power, the target value of active current of the converter is obtained according to the difference between the target value of active power flowing through the converter and the actual value of active power.

Optionally, for the one-side converter configured to control the DC bus voltage, the target active current value of the converter is obtained according to the difference between the target value of the DC bus voltage and the actual value of the DC bus voltage.

Optionally, for the one-side converter configured to control the flow of active power or the one-side converter configured to control the DC bus voltage, the reactive current target value of the converter is based on the converter output reactive power target value and reactive power The difference between the actual power values is obtained.

Optionally, obtaining the target value of the three-phase current of the converter according to the target value of the active current and the target value of the reactive current of the converter includes: calculating the target value of the active current and the target value of the reactive current of the converter according to the phase information of the three-phase voltage of the power grid The target value is transformed from the dq axis to the abc axis to obtain the target value of the three-phase current of the converter.

Optionally, the above-mentioned compensating the target value of the three-phase current of the converter according to the actual value of the three-phase current on the load side to obtain the final target value of the three-phase current of the converter includes: calculating the three-phase current on the load side according to the phase information of the three-phase voltage of the power grid The actual value is transformed from the abc axis to the dq axis, and then after low-pass filtering and PI adjustment, the dq axis components of the compensation current that the converter needs to provide are obtained; according to the phase information of the three-phase voltage of the power grid, the dq axis components of the compensation current are dq Coordinate transformation from axis to abc axis to obtain the three-phase compensation current value; according to the three-phase compensation current value and the target value of the three-phase current of the converter, the final target value of the three-phase current of the converter is obtained.

Optionally, the above-mentioned conversion of the actual value of the three-phase current on the load side from the abc axis to the dq axis according to the phase information of the three-phase voltage of the power grid includes: after inverting the phase information of the three-phase voltage of the power grid, as the three-phase current of the load side The actual value is transformed from the abc axis to the phase information of the dq axis.

Optionally, the coordinate transformation from the dq axis to the abc axis is performed on the dq axis component of the compensation current according to the phase information of the three-phase voltage of the power grid, including: after the phase information of the three-phase voltage of the power grid is reversed, the dq axis of the compensation current Components are transformed from the dq axis to the phase information of the abc axis.

Optionally, the above-mentioned phase information of the three-phase voltage of the grid is obtained by extracting the positive sequence component of the grid voltage, and obtaining it after being phase-locked by a phase-locked loop.

Fig. 5 shows a functional block diagram of a distribution network control method controlling a one-side converter configured to control active power flow.

In some embodiments, the distribution network control method includes: obtaining the active current target value i _d1 ^* of the converter VSC1 according to the difference between the active power target value P ^* and the actual value P of the converter VSC1 ; according to the converter VSC1 Output the difference between the reactive power target value Q ₁ ^* and the reactive power actual value Q ₁ to obtain the reactive current target value i _q1 ^* of the converter VSC1; obtain the phase of the grid three-phase voltage V _1a , V _1b , V _1c Information, according to the phase information of the three-phase voltage V _1a , V _1b , V _1c of the power grid, the active current target value i _d1 ^* and the reactive current target value i _q1 ^* are transformed from the dq axis to the abc axis (Parker inverse transformation), and the obtained Converter VSC1 three-phase current target value i _a1 ^* , i _b1 ^* , i _c1 ^* ; according to the load side three-phase current actual value i _l1,a , i _l1,b , i _l1,c to the VSC1 three-phase current target value i _a1 ^* , i _b1 ^* , i _c1 ^* are compensated to obtain the final target value of the three-phase current of the converter VSC1 i _s1,a ^* , i _s1,b ^* , i _s1,c ^* ; according to the final target of the three-phase current of the converter VSC1 The difference between the value i _s1,a ^* , i _s1,b ^* , i _s1,c ^* and the actual value of the three-phase current of the converter VSC1 i _s1,a , i _s1,b , i _s1,c controls the switch of the converter VSC1 Tube on and off.

The converter VSC1 is configured to control the flow of active power and compensate the unbalanced voltage of the three-phase power grid on the VSC1 side. A current sensor is installed on the load side Load1 of the power grid on this side to measure the actual value of the three-phase current i _l1,a , i on the load side _l1,b , i _l1,c , according to the actual value of the load-side three-phase current i _l1,a , i _l1,b , i _l1,c to the three-phase current target value i _a1 ^* , i _b1 ^* , i _c1 of the converter VSC1 ^* Compensation is performed so that the three-phase voltages V _1a , V _1b , and V _1c of the power grid on this side tend to be balanced.

Optionally, the above-mentioned compensation is performed on the target value of the three-phase current of the converter according to the actual value of the three-phase current on the load side to obtain the final target value of the three-phase current of the converter, including: obtaining the actual value of the three-phase current on the load side i _l1,a , i _l1,b , i _l1,c ; according to the phase information of the three-phase voltage V _1a , V _1b , V _1c of the power grid, the abc axis is performed on the actual value of the three-phase current at the load side i _l1,a , i _l1,b , i _l1,c Transformation to the dq axis (Parker transformation), and then through low-pass filtering and PI adjustment, to obtain the dq axis components i _ld1 ^* and i _lq1 ^* of the compensation current that the converter needs to provide; according to the grid three-phase voltage V _1a , V _1b , The phase information of V _1c performs coordinate transformation from the dq axis to the abc axis (Parker inverse transformation) on the dq axis components i _ld1 ^* and i _lq1 ^* of the compensation current to obtain the three-phase compensation current values Δi _a1 ^* , Δi _b1 ^* , Δi _c1 ^* ; According to the three-phase compensation current values Δi _a1 ^* , Δi _b1 ^* , Δi _c1 ^* and the converter three-phase current target values i _a1 ^* , i _b1 ^* , i _c1 ^* , the final target value i _s1 of the converter three-phase current is obtained _,a ^* , i _s1,b ^* , i _s1,c ^* .

Optionally, the acquisition of the phase information of the grid three-phase voltages V _1a , V _1b , and V _1c includes: extracting the positive sequence components of the grid voltages V _1a , V _1b , and V _1c , and obtaining the grid phase information after being phase-locked by the phase-locked loop PLL. Phase information of the three-phase voltages V _1a , V _1b , V _1c .

Optionally, according to the phase information of the three-phase voltages V _1a , V _1b , V _1c of the power grid, the actual values of the three-phase currents i _l1,a , i _l1,b , i _l1,c on the load side are transformed from the abc axis to the dq axis Transformation, including: after inverting the phase information of the three-phase voltage V _1a , V _1b , V _1c of the power grid, the actual value of the three-phase current on the load side i _l1,a , i _l1,b , i _l1,c is transformed by the abc axis Phase information to the dq axis.

Optionally, according to the phase information of the three-phase voltages V _1a , V _1b , V _1c of the power grid, the dq axis components i _ld1 ^* and i _lq1 ^* of the compensation current are transformed from the dq axis to the abc axis coordinates, including: After the phase information of the phase voltages V _1a , V _1b , and V _1c is reversed, the dq-axis components i _ld1 ^* and i _lq1 ^* of the compensation current are converted from the dq-axis to the phase information of the abc-axis.

Optionally, according to the above-mentioned final target value of the three-phase current of the converter i _s1,a ^* , i _s1,b ^* , i _s1,c ^* and the actual value of the three-phase current of the converter i _s1,a , i _s1,b , i The difference between _s1,c controls the on-off of the switch tube of the converter VSC1, including: the final target value of the three-phase current of the converter i _s1,a ^* , i _s1,b ^* , i _s1,c ^* and the three-phase converter The difference between the actual current values i _s1,a , i _s1,b , and i _s1,c is controlled by a hysteresis loop, and the comparison result is converted into a gate signal of the switch tube of the converter VSC1 to control the on-off of the switch tube.

Optionally, according to the difference between the grid active power target value P ^* and the actual value P, the active current target value i _d1 ^* of the converter is obtained, including: the difference between the grid active power target value P ^* and the actual value P After the output signal of the PI regulator passes through the limiting module, the active current target value i _d1 ^* of the converter is obtained.

Optionally, the direction of active power flow can be controlled by the positive or negative of the active power target value P ^* , for example, a positive value of P ^* indicates that the active power is controlled to flow from the VSC1 side to the VSC2 side, and a negative value of P ^* indicates that the active power is controlled from The VSC2 side flows to the VSC1 side.

Optionally, according to the difference between the output reactive power target value Q ₁ ^* of the converter and the actual reactive power value Q ₁ , the reactive current target value i _q1 ^* of the converter is obtained, including: converting the reactive power of the converter The difference between the target value Q ₁ ^* and the actual value of reactive power Q ₁ is sent to the PI regulator, and the output signal of the PI regulator passes through the limiting module to obtain the reactive current target value component i _q1 ^* of the converter.

Fig. 6 shows a functional block diagram of a distribution network control method controlling a converter configured to control a DC bus voltage.

In some embodiments, the distribution network control method includes: obtaining the active current target value i _d2 ^* of the converter VSC2 according to the difference between the DC bus voltage target value V _dc ^* and the actual value V _dc ; according to the output of the converter VSC2 The difference between the reactive power target value Q ₂ ^* and the actual value Q ₂ is obtained to obtain the reactive current target value i _q2 ^* of the converter VSC2; to obtain the phase information of the three-phase voltage V _2a , V _2b , V _2c of the power grid, according to the power grid The phase information of the three-phase voltage V _2a , V _2b , V _2c transforms the active current target value i _d2 ^* and the reactive current target value i _q2 ^* from the dq axis to the abc axis (Parker inverse transformation), and obtains the converter VSC2 three Phase current target value i _a2 ^* , i _b2 ^* , i _c2 ^* ; according to the actual value of the load side three-phase current i _l2,a , i _l2,b , i _l2,c to the VSC2 three-phase current target value i _a2 ^* , i _b2 ^* and i _c2 ^* are compensated to obtain the final target value i _s2,a ^* of the three-phase current of the converter VSC2, i _s2,b ^* , i _s2,c ^* ; according to the final target value of the three-phase current of the converter VSC2 i _s2, The difference between _a ^* , i _s2,b ^* , i _s2,c ^* and the actual value of the three-phase current of the converter VSC2 i _s2,a , i _s2,b , i _s2,c controls the on-off of the switch tube of the converter VSC2 .

The converter VSC2 is configured to control the DC bus voltage and compensate the unbalanced three-phase voltage of the power grid on the VSC2 side. A current sensor is installed on the load side Load2 of the power grid to measure the actual value of the three-phase current i _l2,a and i on the load side _l2,b , i _l2,c , according to the actual value of the load-side three-phase current i _l2,a , i _l2,b , i _l2,c to the three-phase current target value i _a2 ^* , i _b2 ^* , i _c2 of the converter VSC2 ^* Compensation is performed so that the three-phase voltages V _2a , V _2b , and V _2c of the power grid on this side tend to be balanced.

Optionally, the above-mentioned compensation is performed on the target value of the three-phase current of the converter according to the actual value of the three-phase current on the load side to obtain the final target value of the three-phase current of the converter, including: obtaining the actual value of the three-phase current on the load side i _l2,a , i _l2,b , i _l2,c ; according to the phase information of the three-phase voltage V _2a , V _2b , V _2c of the power grid, the abc axis is performed on the actual value of the three-phase current at the load side i _l2,a , i _l2,b , i _l2,c Transformation to the dq axis (Parker transformation), and then through low-pass filtering and PI adjustment, to obtain the dq axis components i _ld2 ^* and i _lq2 ^* of the compensation current that the converter needs to provide; according to the grid three-phase voltage V _2a , V _2b , The phase information of V _2c performs coordinate transformation from the dq axis to the abc axis (Parker inverse transformation) on the dq axis components i _ld2 ^* and i _lq2 ^* of the compensation current to obtain the three-phase compensation current values Δi _a2 ^* , Δi _b2 ^* , Δi _c2 ^* ; According to the three-phase compensation current values Δi _a2 ^* , Δi _b2 ^* , Δi _c2 ^* and the converter three-phase current target values i _a2 ^* , i _b2 ^* , i _c2 ^* , the final target value i _s2 of the converter three-phase current is obtained _,a ^* , i _s2,b ^* , i _s2,c ^* .

Optionally, the acquisition of the phase information of the grid three-phase voltages V _2a , V _2b , and V _2c includes: extracting the positive sequence components of the grid voltages V _2a , V _2b , and V _2c , and obtaining the grid phase information after being phase-locked by the phase-locked loop PLL. Phase information of the three-phase voltages V _2a , V _2b , V _2c .

Optionally, according to the phase information of the three-phase voltages V _2a , V _2b , and V _2c of the power grid, the actual values of the three-phase currents i _l2,a , i _l2,b , and i _l2,c on the load side are transformed from the abc axis to the dq axis. Transformation, including: after inverting the phase information of the three-phase voltage V _2a , V _2b , V _2c of the grid, as the actual value of the three-phase current on the load side i _l2,a , i _l2,b , i _l2,c are transformed by the abc axis Phase information to the dq axis.

Optionally, according to the phase information of the three-phase voltages V _2a , V _2b , V _2c of the power grid, the dq axis components i _ld2 ^* and i _lq2 ^* of the compensation current are transformed from the dq axis to the abc axis coordinates, including: After the phase information of the phase voltages V _2a , V _2b , and V _2c is reversed, the dq-axis components i _ld2 ^* and i _lq2 ^* of the compensation current are converted from the dq-axis to the phase information of the abc-axis.

Optionally, the above is based on the final target value of the three-phase current i _s2,a ^* , i _s2,b ^* , i _s2,c ^* and the actual value of the three-phase current i _s2,a , i _s2,b , i _s2,c The difference value controls the on-off of the switch tube of the converter VSC2, including: the final target value of the three-phase current of the converter i _{s2, a} ^* , i _{s2, b} ^* , i _{s2, c} ^* and the actual value of the three-phase current of the converter i The difference between _s2,a , i _s2,b and i _s2,c is controlled by hysteresis, and the comparison result is converted into the gate signal of the switch tube of the converter VSC2 to control the on-off of the switch tube.

Optionally, according to the difference between the DC bus voltage target value V _dc ^* and the actual value V _dc , the active current target value i _d2 ^* of the converter is obtained, including: combining the DC bus voltage target value V _dc ^* with the actual value V _dc The difference is sent to the PI regulator, and the output signal of the PI regulator passes through the limiting module to obtain the active current target value i _d2 ^* of the converter.

Optionally, according to the difference between the output reactive power target value Q ₂ ^* of the converter and the actual reactive power value Q ₂ , the reactive current target value i _q2 ^* of the converter is obtained, including: outputting the reactive power of the converter The difference between the power target value Q ₂ ^* and the reactive power actual value Q ₂ is sent to the PI regulator, and the output signal of the PI regulator passes through the limiting module to obtain the reactive current target value component i _q2 ^* of the converter.

In some other embodiments, the present application also proposes a distribution network control system, which respectively controls the converters VSC1 and VSC2 on both sides of the SOP module, including: a first unit configured to obtain the active current target of the converter value. The second unit is configured to obtain a reactive current target value of the converter. The third unit is configured to acquire phase information of the three-phase voltage of the power grid. The fourth unit is configured to convert the active current target value and the reactive current target value from the dq axis to the abc axis (inverse Parker transformation) according to the phase information of the three-phase voltage of the power grid, and obtain the three-phase current target value of the converter. The fifth unit is configured to calculate the three-phase compensation current value according to the actual value of the three-phase current at the load side, and is used to compensate the target value of the three-phase current of the converter. The sixth unit is configured to obtain the final target value of the three-phase current of the converter according to the target value of the three-phase current and the value of the three-phase compensation current; according to the difference between the final target value of the three-phase current of the converter and the actual value of the three-phase current of the converter, Control the on-off of the switch tube of the converter.

Figure 7 illustrates an embodiment of a distribution network control system that controls a side converter configured to control the flow of active power.

An embodiment of the present disclosure provides a distribution network control system, including: a first unit 10 configured to obtain the active current of the converter VSC1 according to the difference between the target value P ^* and the actual value P of the active power flowing through the converter VSC1 Target value i _d1 ^* . The second unit 20 is configured to obtain the reactive current target value i _q1 ^* of the converter VSC1 according to the difference between the reactive power target value Q ₁ ^* output by the converter VSC1 and the reactive power actual value Q ₁ . The third unit 30 is configured to acquire phase information of the grid three-phase voltages V _1a , V _1b , V _1c . The fourth unit 40 is configured to transform the active current target value i _d1 ^* and the reactive _current target _value i _q1 ^* from the dq axis to the abc axis ( _Parker inverse transformation), and obtain the three-phase current target values i _a1 ^* , i _b1 ^* , i _c1 ^* of the converter VSC1. The fifth unit 50 is configured to calculate the three-phase compensation current values Δi _a1 * , Δi _b1 ^* , Δi c1 * according to the actual value of the load-side three-phase current i _l1,a , i _l1,b ^, i _{l1, c} ^, for VSC1 three-phase current target values i _a1 ^* , i _b1 ^* , i _c1 ^* are compensated. _The ^{sixth unit} 60 _is ^configured to ^obtain _{the converter} ^VSC1 _three ^- _phase The final target value of current i _s1,a ^* , i _s1,b ^* , i _s1,c ^* ; according to the final target value of three-phase current of converter VSC1 i s1 _,a ^* , i _s1,b ^* , i _s1,c ^* and The difference between the actual three-phase current values i _s1,a , i _s1,b , and i _s1,c of the converter VSC1 controls the on-off of the switch tube of the converter VSC1.

The converter VSC1 is configured to control the flow of active power and compensate the unbalanced voltage of the three-phase power grid on the VSC1 side. The above system also includes a current sensor installed on the load side Load1 of the power grid on this side to measure the actual value of the three-phase current at the load side i _l1,a , i _l1,b , i _l1,c , according to the actual value of the three-phase current at the load side i _l1,a , i _l1,b , i _l1,c to the three-phase current target value i _a1 ^* , i of the converter VSC1 _b1 ^* and i _c1 ^* perform compensation so that the three-phase voltages V _1a , V _1b , and V _1c of the power grid on this side tend to be balanced.

Optionally, the above system controls the flow direction of active power through the positive or negative value of the active power target value P ^* , for example, a positive value of P ^* means that the active power is controlled to flow from the VSC1 side to the VSC2 side, and a negative value of P ^* means that the active power is controlled Flow from the VSC2 side to the VSC1 side.

Optionally, the above-mentioned first unit 10 includes: a PI regulator and a limiting module, the difference between the active power target value P ^* and the actual active power value P flowing through the converter is sent to the PI regulator, and the output signal of the PI regulator passes through After the limiting module, the active current target value i _d1 ^* of the converter is obtained.

Optionally, the above-mentioned second unit 20 includes: a PI regulator and a limiting module, the difference between the reactive power target value Q ₁ ^* output by the converter and the reactive power actual value Q ₁ is sent to the PI regulator, and the PI regulator After the output signal passes through the limiting module, the reactive current target value component i _q1 ^* of the converter is obtained.

Optionally, the above-mentioned third unit 30 includes: a positive sequence extraction module configured to extract the positive sequence components of the grid voltages V _1a , V _1b , V _1c ; a phase-locked loop PLL that converts the grid voltages V _1a , V _1b , V _1c After the phase-locking of the positive sequence components of , the phase information of the grid three-phase voltage V _1a , V _1b , V _1c is obtained.

Optionally, the above-mentioned fifth unit 50 includes: a current sensor installed on the load side, configured to obtain the actual value i _l1,a , i _l1,b , i _l1,c of the load-side three-phase current; the first transformation unit 51, It is configured to transform the actual values of the three-phase currents i _l1,a , i _l1,b , i _l1,c on the load side from the abc axis to the dq axis according to the phase information of the grid three-phase voltage V _1a , V _1b , V _1c (Parker conversion); low-pass filter and PI regulator, low-pass filtering and PI adjustment are performed on the output signal of the first conversion unit 51, and the dq axis components i _ld1 ^* and i _lq1 ^* of the compensation current that the converter needs to provide are obtained; the second The second transformation unit 52 is configured to perform coordinate transformation from the dq axis to the abc axis on the dq axis components i _ld1 ^* and i _lq1 ^* of the compensation current according to the phase information of the grid three-phase voltage V _1a , V _1b , V _1c (Parker inverse transformation ), to obtain three-phase compensation current values Δi _a1 ^* , Δi _b1 ^* , Δi _c1 ^* .

Optionally, the above-mentioned first conversion unit 51 includes: after inverting the phase information of the grid three-phase voltages V _1a , V _1b , V _1c , as the actual load-side three-phase current values i _l1,a , i _l1,b , i _l1,c is transformed from abc axis to phase information of dq axis.

Optionally, the above-mentioned second conversion unit 52 includes: after inverting the phase information of the grid three-phase voltages V _1a , V _1b , and V _1c , the dq-axis components i _ld1 ^* and i _lq1 ^* of the compensation current are transformed by the dq-axis Phase information to the abc axis.

Optionally, the above-mentioned sixth unit 60 includes: a hysteresis comparator, which compares the final target value of the three-phase current of the converter i _s1,a ^* , i _s1,b ^* , i _s1,c ^* with the actual value of the three-phase current of the converter The difference between i _s1,a , i _s1,b , and i _s1,c is controlled by the hysteresis loop, and the comparison result output by the hysteresis loop comparator is converted into the gate signal of the switch tube of the converter VSC1 to control the on-off of the switch tube.

In some other embodiments, the distribution network control system controls the one-side converter VSC2 configured to control the DC bus voltage. Wherein, the first unit 10 obtains the target active current value _id2 * of the converter VSC2 from the difference between the target value V _dc ^* of the ^DC bus voltage and the actual value V _dc . The second unit 20 is configured to obtain the reactive current target value i _q2 ^* of the converter VSC2 according to the difference between the output reactive power target value Q ₂ ^* of the converter VSC2 and the actual value Q ₂ . The third unit 30 is configured to obtain phase information of the grid three-phase voltages V _2a , V _2b , V _2c . The fourth unit 40 is configured to transform the active current target value i _d2 ^* and the reactive _current target value i _q2 ^* from the dq axis to the abc axis ( _{Parker inverse} transformation), and obtain the three-phase current target values i _a2 ^* , i _b2 ^* , i _c2 ^* of the converter VSC2. The fifth unit 50 is configured to calculate the three-phase compensation current values Δi _a2 * , Δi _b2 ^* , and Δi _c2 * according to the actual value of the load-side three-phase current i _l2,a , i _l2,b , ⁱ _l2, ^c , for VSC2 three-phase current target value i _a2 ^* , i _b2 ^* , i _c2 ^* for compensation. _{The sixth} ^unit 60 _is ^configured to ^{obtain the} _converter ^VSC2 _three ^- _phase The final target value of current i _s2,a ^* , i _s2,b ^* , i _s2,c ^* ; according to the final target value of three-phase current of converter VSC2 i _s2,a ^* , i _s2,b ^* , i _s2,c ^* and The difference between the actual three-phase current values i _s2,a , i _s2,b , and i _s2,c of the converter VSC2 controls the on-off of the switch tube of the converter VSC2.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (9)

1. A distribution network control method, the distribution network includes a SOP module, wherein one side converter of the SOP module is configured to control active power flow, and the other side converter of the SOP module is configured to control the DC bus voltage, which It is characterized in that the converters on both sides of the SOP module are respectively controlled, including: According to the active current target value and the reactive current target value of the converter, the three-phase current target value of the converter is obtained; Compensate the target value of the three-phase current of the converter according to the actual value of the three-phase current on the load side to obtain the final target value of the three-phase current of the converter; According to the difference between the final target value of the three-phase current of the converter and the actual value of the three-phase current of the converter, the on-off of the switch tube of the converter is controlled; Compensating the target value of the three-phase current of the converter according to the actual value of the three-phase current on the load side to obtain the final target value of the three-phase current of the converter includes: According to the phase information of the three-phase voltage of the power grid, the actual value of the three-phase current on the load side is transformed from the abc axis to the dq axis, and then through low-pass filtering and PI adjustment, the dq axis components of the compensation current that the converter needs to provide are obtained; According to the phase information of the three-phase voltage of the power grid, the dq-axis component of the compensation current is transformed from the dq axis to the abc axis to obtain the three-phase compensation current value; According to the three-phase compensation current value and the target value of the three-phase current of the converter, the final target value of the three-phase current of the converter is obtained. 2. A distribution network control method as claimed in claim 1, characterized in that, for the one-side converter configured to control the flow of active power, the active current target value of the converter is based on the active power flowing through the converter The difference between the power target value and the actual value of active power is obtained. 3. A kind of distribution network control method as claimed in claim 1, is characterized in that, for the side converter configured to control the DC bus voltage, the active current target value of the converter is based on the DC bus voltage target value and the actual value of the DC bus voltage to obtain the difference. 4. A kind of distribution network control method as claimed in claim 1, is characterized in that, the reactive current target value of described converter is according to the differential value of converter output reactive power target value and reactive power actual value get. 5. A kind of distribution network control method as claimed in claim 1, is characterized in that, described according to the active current target value of converter and reactive current target value, obtain converter three-phase current target value, comprising: According to the phase information of the three-phase voltage of the grid, the active current target value and the reactive current target value of the converter are transformed from the dq axis to the abc axis, and the three-phase current target value of the converter is obtained. 6. A kind of distribution network control method as claimed in claim 1, is characterized in that, described according to the phase information of grid three-phase voltage, carries out the conversion of abc axis to dq axis to the load side three-phase current actual value, comprises: After the phase information of the three-phase voltage of the power grid is reversed, it is used as the phase information of the actual value of the three-phase current on the load side transformed from the abc axis to the dq axis. 7. A kind of distribution network control method as claimed in claim 1, is characterized in that, described according to the phase information of grid three-phase voltage, carries out the coordinate transformation of dq axis to abc axis to the dq axis component of compensation current, comprising: After the phase information of the three-phase voltage of the power grid is reversed, the dq-axis component of the compensation current is transformed from the dq-axis to the phase information of the abc-axis. 8. A distribution network control method as claimed in any one of claims 5 to 7, characterized in that the phase information of the three-phase voltage of the power grid is: extracting the positive sequence component of the grid voltage, and locking it by a phase-locked loop Obtained later. 9. A kind of distribution network control method as claimed in claim 1, is characterized in that, According to the difference between the final target value of the three-phase current of the converter and the actual value of the three-phase current of the converter, controlling the on-off of the switch tube of the converter includes: the final target value of the three-phase current of the converter and the actual value of the three-phase current of the converter The difference of the value is controlled by hysteresis, and the comparison result is converted into the gate signal of the switch tube of the converter to control the on-off of the switch tube.

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