A high-performance control method for a bipolar energy storage converter

Abstract

This invention belongs to the technical field of energy storage converter control optimization algorithms, and particularly relates to a high-performance control method for a bipolar energy storage converter. The system includes a bipolar energy storage converter comprising an energy storage battery unit, a three-phase dual active full-bridge DC / DC converter, a DC stabilizing capacitor C, and a grid-connected converter. The energy storage battery unit is connected to the intermediate DC stabilizing capacitor C of the grid-connected converter via the three-phase dual active full-bridge DC / DC converter, and the grid-connected converter is directly connected to the AC power grid. This invention allows for more flexible selection and connection of the energy storage battery capacity, and further increases the system's lifespan through a high-performance control method.

Description

Technical Field

[0001] This invention belongs to the technical field of energy storage converter control optimization algorithm, and particularly relates to a high-performance control method for bipolar energy storage converters. Background Technology

[0002] As a key device for the flexible conversion and comprehensive utilization of electrical energy and other energy sources, energy storage can effectively solve the problems of peak-valley load difference and power quality faced by distribution networks, delay the expansion of distribution network equipment, and realize the efficient, clean and safe utilization of energy. Therefore, in recent years, the country has begun to attach importance to the research and development and application of energy storage technology.

[0003] To address the demand for large battery capacity, existing energy storage converters often employ a cascaded approach, but the limited power transmission of a single converter often increases the number of cascaded converters, thereby increasing system costs. At the same time, the frequent charging and discharging demands of energy storage batteries cause problems such as overheating in the converter, which poses a challenge to the converter's reliability. Furthermore, excessive current stress will reduce the converter's operating efficiency, thus affecting the system's lifespan.

[0004] Existing energy storage converter control methods cannot simultaneously meet the three major characteristics of converters: high power transmission range, high reliability, and high efficiency operation. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a high-performance control method for bipolar energy storage converters. The aim is to achieve greater flexibility in energy storage battery capacity selection and connection, and to further extend the system's lifespan through a high-performance control method.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0007] A high-performance control method for a bipolar energy storage converter includes a bipolar energy storage converter comprising an energy storage battery unit, a three-phase dual active full-bridge DC / DC converter, a DC voltage regulator C, and a grid-connected converter. The output terminal of the energy storage battery unit is connected to the input terminal of the three-phase dual active full-bridge DC / DC converter, the output terminal of the three-phase dual active full-bridge DC / DC converter is connected to the DC voltage regulator C, the other end of the DC voltage regulator C is connected to the input terminal of the grid-connected converter, and the output terminal of the grid-connected converter is directly connected to the AC power grid.

[0008] Furthermore, the connection method of the three-phase dual active full-bridge DC / DC converter is as follows: it includes a switching transistor Q 11 and switching transistor Q 14 Switching transistor Q 13 and switching transistor Q 16 Switching transistor Q15 and switching transistor Q 12 Switching transistor Q 21 and switching transistor Q 24 Switching transistor Q 23 and switching transistor Q 26 Switching transistor Q 25 and switching transistor Q 22 The bridge consists of 6 arms; and is composed of switching transistor Q. 11 and switching transistor Q 14 Switching transistor Q 13 and switching transistor Q 16 Switching transistor Q 15 and switching transistor Q 12 Switching transistor Q 21 and switching transistor Q 24 The collector of the upper switching transistor in the three-arm bridge is connected to the positive terminal of the energy storage battery cell, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the energy storage battery cell; the switching transistor Q... 21 and switching transistor Q 24 Switching transistor Q 23 and switching transistor Q 26 Switching transistor Q 25 and switching transistor Q 22 The collector of the upper switching transistor in the three bridge arms is connected to the positive terminal of the DC regulated capacitor C, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the DC regulated capacitor C; the positive terminal of the primary side of the first high-frequency transformer Ta is connected to the leakage inductance L. a Connect to Q 11 The emitter of the switching transistor is simultaneously connected to the negative primary terminal of the third high-frequency transformer Tc, and the negative primary terminal of the first high-frequency transformer Ta is connected to Q. 13 The emitter of the switching transistor and through the leakage inductance L b Connected to the positive primary terminal of the second high-frequency transformer Tb; the positive primary terminal of the second high-frequency transformer Tb is connected through the leakage inductance L b Connect to Q 13 The emitter of the switching transistor is connected to the negative terminal of the primary winding of the first high-frequency transformer Ta, and the negative terminal of the primary winding of the second high-frequency transformer Tb is connected to Q. 15 The emitter of the switching transistor and through the leakage inductance L c Connected to the positive primary terminal of the third high-frequency transformer Tc; the positive primary terminal of the third high-frequency transformer Tc is connected through the leakage inductance L c Connect to Q 15 The emitter of the switching transistor is connected to the negative terminal of the primary winding of the second high-frequency transformer Tb, and the negative terminal of the primary winding of the third high-frequency transformer Tc is connected to Q. 11 The emitter of the switching transistor and through the leakage inductance L a Connected to the positive terminal of the primary side of the first high-frequency transformer Ta; the positive terminal of the secondary side of the first high-frequency transformer Ta is connected to Q.21 The emitter of the switching transistor is also connected to the negative terminal of the secondary side of the third high-frequency transformer Tc, and the negative terminal of the secondary side of the first high-frequency transformer Ta is connected to Q. 23 The emitter of the switching transistor and the positive terminal of the secondary side of the second high-frequency transformer Tb; the positive terminal of the secondary side of the second high-frequency transformer Ta is connected to Q. 23 The emitter of the switching transistor is connected to the negative terminal of the secondary side of the first high-frequency transformer Ta, and the negative terminal of the secondary side of the second high-frequency transformer Tb is connected to Q. 25 The emitter of the switching transistor and the positive terminal of the secondary side of the third high-frequency transformer Tc; the positive terminal of the secondary side of the third high-frequency transformer Tc is connected to Q. 25 The emitter of the switching transistor is also connected to the negative terminal of the secondary side of the second high-frequency transformer Tb, and the negative terminal of the secondary side of the third high-frequency transformer Tc is connected to Q. 21 The emitter of the switching transistor and the positive terminal of the secondary side of the first high-frequency transformer Ta.

[0009] Furthermore, the grid-connected converter includes two bridge arms consisting of switching transistors S1 and S4, and switching transistors S2 and S3. The collector of the upper switching transistor in each bridge arm is connected to the positive terminal of the DC voltage regulator C, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the DC voltage regulator C. The emitter of switching transistor S2 is connected to one end of the AC grid through the filter capacitor L of the grid-connected converter, and the other end of the AC grid is connected to the emitter of switching transistor S1.

[0010] Furthermore, the control of the bipolar energy storage converter includes: energy storage battery cell SOC identification, high-performance control of the three-phase dual active full-bridge DC / DC converter, AC grid voltage phase-locking, and grid-connected converter grid-connected control.

[0011] Furthermore, the energy storage battery cell SOC identification includes:

[0012] Step 101. Identify the SOC value of the energy storage battery through the energy storage battery management system and proceed to the energy storage battery status judgment stage;

[0013] Step 102. The energy storage battery status determination process categorizes the energy storage battery cell status into:

[0014] The energy storage battery is not working and is in a prohibited operating state.

[0015] When SOC sample SOC set_max The energy storage battery has too high a charge level and can only be discharged.

[0016] When SOC sample <SOC set_min The energy storage battery has too low a charge level and can only be charged.

[0017] When SOCset_min <SOC sample <SOC set_max The energy storage battery capacity meets the requirements for energy storage to participate in grid peak shaving / frequency regulation and is in normal operating condition; among which, SOC sample SOC set_max SOC set_min These are the SOC identification values ​​of the energy storage battery at the time of data collection, and the maximum and minimum control values ​​are set.

[0018] Step 103. The energy storage battery status judgment stage determines the next operating status of the energy storage battery unit based on the upper-level scheduling instructions and the current status of the energy storage battery unit, and sends it to the high-performance control stage of the three-phase dual active full-bridge DC / DC converter.

[0019] Furthermore, the high-performance control of the three-phase dual active full-bridge DC / DC converter includes:

[0020] Step 201. Set the operating power value of the three-phase dual active full-bridge DC / DC converter according to the superior dispatch instruction;

[0021] Step 202. Based on the energy storage battery cell status identified by the SOC of the energy storage battery cell, select the high-performance control mode of the three-phase dual active full-bridge DC / DC converter according to the range of the operating power value; the high-performance control mode of the converter includes three-phase mode, single-phase high-power mode and single-phase low-power mode.

[0022] Step 203. The three-phase dual active full-bridge DC / DC converter generates the phase shift duty cycle under the corresponding control mode based on the high-performance control mode of the three-phase dual active full-bridge DC / DC converter.

[0023] Step 204. Based on the generated phase shift duty cycle, the PWM modulation stage generates PWM trigger pulses for the six bridge arms of the three-phase dual active full-bridge DC / DC converter to drive the converter to operate at high performance.

[0024] Furthermore, the AC grid voltage phase-locked loop uses a SOGI-PLL single-phase phase-locked loop to calculate the active phase of the AC grid and output it to the grid-connected converter grid-connected control loop.

[0025] Furthermore, the grid-connected converter grid-connected control circuit includes:

[0026] Step 301. Collect the DC regulated capacitor voltage and grid-connected current;

[0027] Step 302. Set the voltage setpoint for the DC regulated capacitor;

[0028] Step 303. The difference between the DC regulated capacitor voltage value and the given value is used to generate the grid-connected current amplitude given value through the DC voltage control outer loop;

[0029] Step 304. Multiply the given value of the grid-connected current amplitude by the active phase of the AC grid, and then subtract the difference from the grid-connected current. This difference is then used to generate an SPWM modulation wave through the AC current control inner loop for modulation of the grid-connected converter.

[0030] Step 305. Generate drive pulse signals for the four switching transistors of the grid-connected converter to drive the converter to operate in grid-connected mode.

[0031] A computer device includes a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, wherein the processor executes the computer program to implement the steps of any of the above-described high-performance control methods for a bipolar energy storage converter.

[0032] A computer storage medium storing a computer program, wherein when the computer program is executed by a processor, the steps of any of the above-described high-performance control methods for a bipolar energy storage converter are implemented.

[0033] The present invention has the following beneficial effects and advantages:

[0034] This invention provides a high-performance control method for a bipolar energy storage converter. The grid-connected converter control can achieve unity power factor control and is decoupled from the energy storage battery control on the DC / DC converter stage side. The DC / DC converter stage adopts a three-phase dual active full-bridge DC / DC converter with a higher transmission power level to meet the access requirements of higher power level energy storage batteries. Three modes are designed for the DC / DC converter: three-phase mode, single-phase high-power mode, and single-phase low-power mode, for high-performance regulation. Based on the single-phase high-power and single-phase low-power modes, the two bridge arms are always alternately stopped, which is conducive to heat dissipation of devices and improves reliability. Based on the low-power mode, the minimum current stress optimization algorithm is used to reduce operating losses and improve the overall operating efficiency of the system. Based on the three-phase mode, the transmission power level of the converter can be increased. In the alternately stopped state, the switching transistors of the corresponding bridge arms do not generate losses, ensuring the loss balance of the three-phase bridge arms.

[0035] This invention adopts a bipolar energy storage converter topology, studies a unit converter, and proposes a corresponding high-performance control strategy.

[0036] This invention allows for more flexible selection and connection of energy storage battery capacity, and the high-performance control method further increases the system's lifespan. Attached Figure Description

[0037] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0038] Figure 1 This is a topology diagram of the bipolar energy storage converter of the present invention;

[0039] Figure 2 This is a control block diagram of the high-performance control method for bipolar energy storage converter of the present invention;

[0040] Figure 3 This invention provides a switching sequence diagram of the three-phase dual active full-bridge DC / DC converter in three-phase mode, as well as the primary and secondary voltage waveforms of the three-phase high-frequency transformer and the current waveform of the inductor.

[0041] Figure 4 This invention provides a switching sequence diagram of the three-phase dual active full-bridge DC / DC converter in single-phase high-power mode, as well as the primary and secondary voltage waveforms of the three-phase high-frequency transformer and the current waveform of the inductor.

[0042] Figure 5 This invention provides a switching sequence diagram of the three-phase dual active full-bridge DC / DC converter in single-phase low-power mode, as well as the primary and secondary voltage waveforms of the three-phase high-frequency transformer and the current waveform of the inductor.

[0043] Figure 6 This is a flowchart of the current stress optimization control of the present invention. Detailed Implementation

[0044] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0045] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0046] The following reference Figures 1-6 The technical solutions of some embodiments of the present invention are described below.

[0047] Example 1

[0048] This invention provides an embodiment of a high-performance control method for a bipolar energy storage converter, which is a high-performance energy storage converter control method with higher unit transmission power, transmission efficiency and reliability.

[0049] like Figure 1 As shown, Figure 1 This is a topology diagram of the bipolar energy storage converter of the present invention. The bipolar energy storage converter of the present invention includes an energy storage battery unit, a three-phase dual active full-bridge DC / DC converter, a DC voltage regulator capacitor C, and a grid-connected converter.

[0050] The output terminal of the energy storage battery unit is connected to the input terminal of a three-phase dual active full-bridge DC / DC converter. The output terminal of the three-phase dual active full-bridge DC / DC converter is connected to a DC voltage regulator capacitor C. The other end of the DC voltage regulator capacitor C is connected to the input terminal of a grid-connected converter. The output terminal of the grid-connected converter is directly connected to the AC power grid. s The port voltage of the energy storage battery unit is U1, and the current is i1, U C This is the voltage of the intermediate DC regulated capacitor.

[0051] In the aforementioned three-phase dual-active full-bridge DC / DC converter, the high-frequency transformer has a turns ratio of n:1, L a L b L c These are the equivalent leakage inductance of the three-phase high-frequency transformer (Ta, Tb, Tc) and the line, respectively. La i Lb i Lc These are the three-phase equivalent leakage inductance currents; fs is defined as the switching frequency of each switching transistor in the three-phase dual active full-bridge DC / DC converter; Q 11 -Q 26 D is the switching transistor of a three-phase dual active full-bridge DC / DC converter. 11 -D 26 S1-S4 are the anti-parallel diodes corresponding to each switching transistor; D1-D4 are the switching transistors of the grid-connected converter; L is the filter capacitor of the grid-connected converter.

[0052] The connection method of the three-phase dual-active full-bridge DC / DC converter is as follows: it includes a switching transistor Q 11 and switching transistor Q 14 Switching transistor Q 13 and switching transistor Q 16 Switching transistor Q 15 and switching transistor Q 12 Switching transistor Q 21 and switching transistor Q 24 Switching transistor Q 23 and switching transistor Q 26 Switching transistor Q 25 and switching transistor Q 22 The bridge consists of six arms. It is powered by the switching transistor Q. 11 and switching transistor Q 14 Switching transistor Q 13 and switching transistor Q 16 Switching transistor Q 15 and switching transistor Q 12 Switching transistor Q 21 and switching transistor Q 24The collector of the upper switching transistor in the three-arm bridge is connected to the positive terminal of the energy storage battery cell, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the energy storage battery cell; the switching transistor Q... 21 and switching transistor Q 24 Switching transistor Q 23 and switching transistor Q 26 Switching transistor Q 25 and switching transistor Q 22 The collector of the upper switching transistor in the three bridge arms is connected to the positive terminal of the DC regulated capacitor C, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the DC regulated capacitor C. The positive terminal of the primary side of the first high-frequency transformer Ta is connected through the leakage inductance L. a Connect to Q 11 The emitter of the switching transistor is simultaneously connected to the negative primary terminal of the third high-frequency transformer Tc, and the negative primary terminal of the first high-frequency transformer Ta is connected to Q. 13 The emitter of the switching transistor and through the leakage inductance L b Connected to the positive primary terminal of the second high-frequency transformer Tb; the positive primary terminal of the second high-frequency transformer Tb is connected through the leakage inductance L b Connect to Q 13 The emitter of the switching transistor is connected to the negative terminal of the primary winding of the first high-frequency transformer Ta, and the negative terminal of the primary winding of the second high-frequency transformer Tb is connected to Q. 15 The emitter of the switching transistor and through the leakage inductance L c Connected to the positive primary terminal of the third high-frequency transformer Tc; the positive primary terminal of the third high-frequency transformer Tc is connected through the leakage inductance L c Connect to Q 15 The emitter of the switching transistor is connected to the negative terminal of the primary winding of the second high-frequency transformer Tb, and the negative terminal of the primary winding of the third high-frequency transformer Tc is connected to Q. 11 The emitter of the switching transistor and through the leakage inductance L a Connected to the positive terminal of the primary side of the first high-frequency transformer Ta; the positive terminal of the secondary side of the first high-frequency transformer Ta is connected to Q. 21 The emitter of the switching transistor is also connected to the negative terminal of the secondary side of the third high-frequency transformer Tc, and the negative terminal of the secondary side of the first high-frequency transformer Ta is connected to Q. 23 The emitter of the switching transistor and the positive terminal of the secondary side of the second high-frequency transformer Tb; the positive terminal of the secondary side of the second high-frequency transformer Ta is connected to Q. 23 The emitter of the switching transistor is connected to the negative terminal of the secondary side of the first high-frequency transformer Ta, and the negative terminal of the secondary side of the second high-frequency transformer Tb is connected to Q. 25 The emitter of the switching transistor and the positive terminal of the secondary side of the third high-frequency transformer Tc; the positive terminal of the secondary side of the third high-frequency transformer Tc is connected to Q. 25 The emitter of the switching transistor is also connected to the negative terminal of the secondary side of the second high-frequency transformer Tb, and the negative terminal of the secondary side of the third high-frequency transformer Tc is connected to Q. 21The emitter of the switching transistor and the positive terminal of the secondary side of the first high-frequency transformer Ta.

[0053] The grid-connected converter is connected as follows: it comprises two bridge arms consisting of switching transistors S1 and S4, and switching transistors S2 and S3. The collector of the upper switching transistor in each bridge arm is connected to the positive terminal of the DC regulated capacitor C, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the DC regulated capacitor C. The emitter of switching transistor S2 is connected to one end of the AC grid through the filter capacitor L of the grid-connected converter, and the other end of the AC grid is connected to the emitter of switching transistor S1.

[0054] Example 2

[0055] This invention provides another embodiment of a high-performance control method for a bipolar energy storage converter, specifically a high-performance energy storage converter control method with higher unit transmission power, transmission efficiency, and reliability.

[0056] The control of the bipolar energy storage converter is divided into four stages: energy storage battery unit SOC identification, high-performance control of the three-phase dual active full-bridge DC / DC converter, AC grid voltage phase-locking, and grid-connected converter grid-connected control.

[0057] The three-phase dual active full-bridge DC / DC converter includes a three-phase high-frequency transformer and two three-phase H-bridges on both sides, namely phase A, phase B, and phase C. It is only responsible for charging or discharging control of the energy storage battery unit and is decoupled from the grid-connected converter grid control. Compared with the traditional single-phase dual active full-bridge DC / DC converter, it has a higher power transmission range.

[0058] The grid-connected converter is responsible for maintaining the voltage value U of the intermediate DC voltage regulator capacitor C. C Stable, while enabling power exchange between the energy storage battery and the AC grid;

[0059] like Figure 2 As shown, Figure 2 The control block diagram for a high-performance control method for a bipolar energy storage converter includes the following steps in the SOC identification step of the energy storage battery unit:

[0060] Step 101. Identify the SOC value of the energy storage battery through the energy storage battery management system and proceed to the energy storage battery status judgment stage;

[0061] Step 102. The energy storage battery status determination process categorizes the energy storage battery cell status into four types:

[0062] The energy storage battery is not working and is in a prohibited operating state.

[0063] When SOC sample SOC set_maxThe energy storage battery has too high a charge level and can only be discharged.

[0064] When SOC sample <SOC set_min The energy storage battery has too low a charge level and can only be charged.

[0065] When SOC set_min <SOC sample <SOC set_max The energy storage battery capacity meets the requirements for energy storage to participate in grid peak shaving / frequency regulation and is in normal operating condition;

[0066] Among them, SOC sample SOC set_max SOC set_min These are the SOC identification values ​​of the energy storage battery at the time of data collection, and the maximum and minimum control values ​​are set.

[0067] Step 103. The energy storage battery status judgment stage determines the next operating status of the energy storage battery unit based on the upper-level scheduling instructions and the current status of the energy storage battery unit, and sends it to the high-performance control stage of the three-phase dual active full-bridge DC / DC converter.

[0068] The high-performance control of the three-phase dual active full-bridge DC / DC converter includes the following steps:

[0069] Step 201. Set the operating power value Pref of the three-phase dual active full-bridge DC / DC converter according to the superior dispatch instruction;

[0070] Step 202. Based on the energy storage battery cell status obtained in Step 103, select the high-performance control mode of the three-phase dual active full-bridge DC / DC converter according to the range of the operating power value Pref.

[0071] Step 203. Based on the high-performance control mode of the three-phase dual active full-bridge DC / DC converter selected in step 202, the phase shift duty cycle of the corresponding control mode is generated.

[0072] Step 204. Based on the phase shift duty cycle generated in step 203, the PWM modulation stage generates PWM trigger pulses for the six bridge arms of the three-phase dual active full-bridge DC / DC converter to drive the converter to operate at high performance.

[0073] The converter's high-performance control modes include three-phase mode, single-phase high-power mode, and single-phase low-power mode.

[0074] like Figure 3 As shown, Figure 3 The diagram shows the switching sequence of a three-phase dual active full-bridge DC / DC converter in three-phase mode, the primary and secondary voltage waveforms of the three-phase high-frequency transformer, and the current waveform of the inductor. V is shown in the diagram.AB V BC V CA V represents the line voltage between the midpoints of the H-bridge arms of each phase on the primary side of the three-phase high-frequency transformer in a three-phase dual active full-bridge DC / DC converter. ab V bc V ca The line voltage between the midpoints of the H-bridge arms of each phase on the secondary side of the three-phase high-frequency transformer in a three-phase dual active full-bridge DC / DC converter is given in nV. ab nV bc nV ca The voltage between the midpoints of each phase H-bridge arm on the secondary side of the three-phase high-frequency transformer is referred to the primary side as the line voltage; the upper and lower bridge arm switching transistors Q 11 Q 14 The drive complementarity, the upper and lower bridge arm switching transistors Q 21 Q 24 The driving forces are complementary, and Q 11 Q 14 The drive signal and Q 21 Q 24 The drive signals have a certain interval, which is defined as the phase shift duty cycle D. A upper and lower bridge arm switch Q 13 Q 16 The drive complementarity, the upper and lower bridge arm switching transistors Q 23 Q 26 Driven by complementarity, Q 13 Q 16 The drive signal and Q 11 Q 14 Drive signal interval 120°, Q 13 Q 16 The drive signal and Q 23 Q 26 The drive signals have a certain interval, and the defined interval of the control drive signals is also the phase shift duty cycle D. A upper and lower bridge arm switch Q 14 Q 12 The drive complementarity, the upper and lower bridge arm switching transistors Q 24 Q 22 Driven by complementarity, Q 14 Q 12 The drive signal and Q 13 Q 16 Drive signal interval 120°, Q 14 Q 12 The drive signal and Q 24 Q 22 The drive signals have a certain interval, and the defined interval of the control drive signals is also the phase shift duty cycle D. A .

[0075] When 9 / 14Pmax < Pref ≤ Pmax, the three-phase dual-active full-bridge DC / DC converter is regulated in the three-phase mode, and the specific steps are as follows:

[0076] A1. The phase-shift duty cycle D in the three-phase mode A generates PWM trigger pulses for the six bridge arms of the three-phase dual-active full-bridge DC / DC converter through the PWM modulation link; where D A is obtained from the functional relationship corresponding to the phase-shift duty cycle and the specified operating power value Pref, that is, D A = f(D A );

[0077] A2. The drive pulse signals of the six bridge arms are given to the twelve switching tubes of the converter to achieve three-phase mode operation;

[0078] As Figure 4 shown, Figure 4 is the switching sequence diagram, the primary and secondary side voltage waveforms of the three-phase high-frequency transformer, and the current waveform of the inductor of the three-phase dual-active full-bridge DC / DC converter in the single-phase high-power mode. Taking the C-phase bridge arm as an example of wheel-stop, the same applies to the A-phase or B-phase wheel-stop. In the figure, V AB is the line voltage between the midpoints of the H-bridge arms of the A-phase and B-phase on the primary side of the three-phase high-frequency transformer of the three-phase dual-active full-bridge DC / DC converter, V ab is the line voltage between the midpoints of the H-bridge arms of the A-phase and B-phase on the secondary side of the three-phase high-frequency transformer of the three-phase dual-active full-bridge DC / DC converter, nV ab is the voltage of the line voltage between the midpoints of the H-bridge arms of the A-phase and B-phase on the secondary side of the three-phase high-frequency transformer folded to the primary side; the drive of the upper and lower bridge arm switching tubes Q 11 and Q 14 is complementary, the drive of the upper and lower bridge arm switching tubes Q 21 and Q 24 is complementary, and the drive signals of Q 11 and Q 14 have a certain interval from the drive signals of Q 21 and Q 24 . The defined interval of the control drive signal is the phase-shift duty cycle D B ; the drive of the upper and lower bridge arm switching tubes Q 13 and Q 16 is complementary, the drive of the upper and lower bridge arm switching tubes Q 23 and Q 26 is complementary, the drive signals of Q 13 and Q 16 have an interval of 180° from the drive signals of Q 11 and Q 14 , and the drive signals of Q 13 and Q 16 have an interval from the drive signals of Q 23 and Q 26The driving signals have a certain interval, and the defined interval for controlling the driving signals is also the phase-shifted duty cycle D B .

[0079] When 1 / 2Pmax < Pref ≤ 9 / 14Pmax, the three-phase dual-active-bridge DC / DC converter is regulated in the single-phase high-power mode, and the specific steps are as follows:

[0080] B1. Stop one of the same-phase bridge arms in the H-bridges on the left and right sides of the high-frequency transformer. In this case, the C-phase is taken as an example for stopping

[0081] B2. The phase-shifted duty cycle D B in the two-phase high-power mode is used to generate the driving pulses for the remaining 4 bridge arms of the three-phase dual-active-bridge DC / DC converter through the PWM modulation link; where D B is obtained from the function relationship corresponding to the phase-shifted duty cycle and the specified operating power value Pref, that is, D B = f(D B );

[0082] B3. The driving pulse signals of the remaining 4 bridge arms are given to the 8 switching tubes of the converter to achieve single-phase high-power mode operation

[0083] As Figure 5 shown Figure 5 is the switching sequence diagram, the primary and secondary side voltage waveforms of the three-phase high-frequency transformer, and the current waveform of the inductor of the three-phase dual-active-bridge DC / DC converter in the single-phase low-power mode. Taking the C-phase bridge arm stop as an example, the situation is the same when the A-phase or B-phase is stopped. In the figure, V AB is the line voltage between the midpoints of the A-phase and B-phase H-bridge arms on the primary side of the three-phase high-frequency transformer of the three-phase dual-active-bridge DC / DC converter, V ab is the line voltage between the midpoints of the A-phase and B-phase H-bridge arms on the secondary side of the three-phase high-frequency transformer of the three-phase dual-active-bridge DC / DC converter, nV ab is the voltage of the line voltage between the midpoints of the A-phase and B-phase H-bridge arms on the secondary side of the three-phase high-frequency transformer folded to the primary side; the driving of the upper and lower bridge arm switching tubes Q 11 , Q 14 is complementary, the driving of the upper and lower bridge arm switching tubes Q 21 , Q 24 is complementary, and the driving signals of Q 11 , Q 14 have a certain interval from the driving signals of Q 21 , Q 24 . The defined interval for controlling the driving signals is the phase-shifted duty cycle D2; the driving of the upper and lower bridge arm switching tubes Q 13 , Q 16 is complementary, the driving of the upper and lower bridge arm switching tubes Q 23 , Q 26 is complementary. Define Q13 The drive signal of 11 The interval between the drive signals is the phase-shifted duty cycle D1, 13 , 16 The drive signal of 23 , 26 There is a certain interval between the drive signals, and the defined interval for controlling the drive signals is also the phase-shifted duty cycle D2.

[0084] When 0 < Pref ≤ 1 / 2Pmax, a single-phase low-power mode is adopted to control the three-phase dual-active full-bridge DC / DC converter. The specific steps are as follows:

[0085] C1. Stop one of the same-phase bridge arms in the H-bridges on both sides of the high-frequency transformer. In this case, the C-phase is stopped as an example;

[0086] C2. Figure 6 It is the current stress optimization control flow chart. Based on the voltage and current waveforms at both sides of the inductor in the three-phase dual-active full-bridge DC / DC converter under steady state, the current stress of the converter based on DPS in the cases of 0 < D1 ≤ D2 < 1 and 0 < D2 < D1 < 1 is deduced and normalized; where D1 and D2 are the inner and outer phase-shifted duty cycles respectively;

[0087] C3. Taking the minimum current stress as the optimization goal, the relationship between the phase-shifted duty cycles that satisfies the minimum current stress in different power operation ranges of the converter is obtained, that is, (D1, D2) = f(D1, D2);

[0088] C4. Generate the phase-shifted duty cycles in the two-phase low-power mode and generate the drive pulses for the remaining 4 bridge arms of the three-phase dual-active full-bridge DC / DC converter through the PWM modulation link;

[0089] C5. Feed the drive pulse signals of the remaining 4 bridge arms to the 8 switching tubes of the converter to achieve single-phase high-power mode operation;

[0090] In the single-phase high-power mode and single-phase low-power mode of the converter, the same-phase bridge arms in the H-bridges on both sides adopt a fixed switching cycle stop mechanism in turn to ensure loss balance.

[0091] [[ID=3​​​​​​​​Where s represents the differential operator of the Laplace transform; w represents the resonant frequency of the AC grid voltage phase-locked loop, which is the same as the grid frequency; and k is the closed-loop coefficient.

[0095] SOGI-PLL single-phase phase-locked loop is existing technology, and the relevant variables are well-known, so they will not be elaborated here.

[0096] The grid-connected converter grid-connected control circuit of the present invention includes the following steps:

[0097] Step 301. Set the DC regulated capacitor voltage UC and the grid-connected current i. g Collect data;

[0098] Step 302. Set the voltage setpoint U of the DC regulated capacitor. Cref ;

[0099] Step 303. The difference between the DC regulated capacitor voltage and the given value is used to generate the grid-connected current amplitude given value i through the DC voltage control outer loop. gref ;

[0100] Step 304. Multiply the given value of the grid-connected current amplitude by the active phase of the AC grid and then subtract it from the grid-connected current. The result is used to generate an SPWM modulation wave uo through the AC current control inner loop for modulation of the grid-connected converter.

[0101] Step 305. Generate drive pulse signals for the four switching transistors of the grid-connected converter to drive the converter to operate in grid-connected mode.

[0102] The SPWM stage is existing technology, and the related switching action sequence is well-known, so it will not be elaborated here.

[0103] Example 3

[0104] Based on the same inventive concept, embodiments of the present invention also provide a computer device, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor. When the processor executes the computer program, it implements the steps of any of the high-performance control methods for bipolar energy storage converters described in Embodiment 1 or 2.

[0105] Example 4

[0106] Based on the same inventive concept, this embodiment of the invention also provides a computer storage medium storing a computer program, which, when executed by a processor, implements the steps of any of the bipolar energy storage converter high-performance control methods described in embodiment 1 or 2.

[0107] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0108] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0109] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0110] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0111] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. A high-performance control method for a bipolar energy storage converter, characterized by: The system includes a bipolar energy storage converter, comprising an energy storage battery unit, a three-phase dual active full-bridge DC / DC converter, a DC voltage regulator C, and a grid-connected converter. The output of the energy storage battery unit is connected to the input of the three-phase dual active full-bridge DC / DC converter. The output of the three-phase dual active full-bridge DC / DC converter is connected to the DC voltage regulator C. The other end of the DC voltage regulator C is connected to the input of the grid-connected converter, whose output is directly connected to the AC power grid. The three-phase dual active full-bridge DC / DC converter is connected via a switching transistor Q. 11 and switching transistor Q 14 Switching transistor Q 13 and switching transistor Q 16 Switching transistor Q 15 and switching transistor Q 12 Switching transistor Q 21 and switching transistor Q 24 Switching transistor Q 23 and switching transistor Q 26 Switching transistor Q 25 and switching transistor Q 22 The bridge consists of 6 arms; and is composed of switching transistor Q. 11 and switching transistor Q 14 Switching transistor Q 13 and switching transistor Q 16 Switching transistor Q 15 and switching transistor Q 12 Switching transistor Q 21 and switching transistor Q 24 The collector of the upper switching transistor in the three-arm bridge is connected to the positive terminal of the energy storage battery cell, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the energy storage battery cell; the switching transistor Q... 21 and switching transistor Q 24 Switching transistor Q 23 and switching transistor Q 26 Switching transistor Q 25 and switching transistor Q 22 The collector of the upper switching transistor in the three bridge arms is connected to the positive terminal of the DC regulated capacitor C, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the DC regulated capacitor C; the positive terminal of the primary side of the first high-frequency transformer Ta is connected through the leakage inductance... L a Connect to Q 11 The emitter of the switching transistor is simultaneously connected to the negative primary terminal of the third high-frequency transformer Tc, and the negative primary terminal of the first high-frequency transformer Ta is connected to Q. 13 The emitter of the switching transistor and through the leakage inductance L b Connected to the positive primary terminal of the second high-frequency transformer Tb; the positive primary terminal of the second high-frequency transformer Tb is connected through leakage inductance. L b Connect to Q 13 The emitter of the switching transistor is connected to the negative terminal of the primary winding of the first high-frequency transformer Ta, and the negative terminal of the primary winding of the second high-frequency transformer Tb is connected to Q. 15 The emitter of the switching transistor and through the leakage inductance L c Connected to the positive primary terminal of the third high-frequency transformer Tc; the positive primary terminal of the third high-frequency transformer Tc is connected through leakage inductance. L c Connect to Q 15 The emitter of the switching transistor is connected to the negative terminal of the primary winding of the second high-frequency transformer Tb, and the negative terminal of the primary winding of the third high-frequency transformer Tc is connected to Q. 11 The emitter of the switching transistor and through the leakage inductance L a Connected to the positive terminal of the primary side of the first high-frequency transformer Ta; the positive terminal of the secondary side of the first high-frequency transformer Ta is connected to Q. 21 The emitter of the switching transistor is also connected to the negative terminal of the secondary side of the third high-frequency transformer Tc, and the negative terminal of the secondary side of the first high-frequency transformer Ta is connected to Q. 23 The emitter of the switching transistor and the positive terminal of the secondary side of the second high-frequency transformer Tb; the positive terminal of the secondary side of the second high-frequency transformer Ta is connected to Q. 23 The emitter of the switching transistor is connected to the negative terminal of the secondary side of the first high-frequency transformer Ta, and the negative terminal of the secondary side of the second high-frequency transformer Tb is connected to Q. 25 The emitter of the switching transistor and the positive terminal of the secondary side of the third high-frequency transformer Tc; the positive terminal of the secondary side of the third high-frequency transformer Tc is connected to Q. 25 The emitter of the switching transistor is also connected to the negative terminal of the secondary side of the second high-frequency transformer Tb, and the negative terminal of the secondary side of the third high-frequency transformer Tc is connected to Q. 21 The emitter of the switching transistor and the positive terminal of the secondary side of the first high-frequency transformer Ta; the grid-connected converter consists of two bridge arms composed of switching transistors S1 and S4, and switching transistors S2 and S3; the collector of the upper switching transistor in each bridge arm is connected to the positive terminal of the DC regulated capacitor C, the emitter of the upper switching transistor is connected to the collector of the lower switching transistor, and the emitter of the lower switching transistor is connected to the negative terminal of the DC regulated capacitor C; the emitter of switching transistor S2 is connected to the filter capacitor of the grid-connected converter. L One end connected to the AC power grid ， The other end of the AC grid is connected to the emitter of the switching transistor S1; the control of the bipolar energy storage converter includes: energy storage battery unit SOC identification, high-performance control of the three-phase dual active full-bridge DC / DC converter, AC grid voltage phase-locking and grid-connected converter grid-connected control.

2. The high-performance control method for a bipolar energy storage converter according to claim 1, characterized in that: The energy storage battery unit SOC identification includes: Step 101. Identify the SOC value of the energy storage battery through the energy storage battery management system and proceed to the energy storage battery status judgment stage; Step 102. The energy storage battery status determination process categorizes the energy storage battery cell status into: The energy storage battery is not working and is in a prohibited operating state. When the SOC sample SOC set_max , the energy storage battery is too high and can only be discharged. When the SOC sample <SOC set_min , the energy storage battery is too low and can only be charged. When SOC set_min <SOC sample <SOC set_max The energy storage battery capacity meets the requirements for energy storage to participate in grid peak shaving / frequency regulation and is in normal operating condition; among which, SOC sample SOC set_max、 SOC set_min These are the SOC identification values ​​of the energy storage battery at the time of data collection, and the maximum and minimum control values ​​are set. Step 103. The energy storage battery status judgment stage determines the next operating status of the energy storage battery unit based on the upper-level scheduling instructions and the current status of the energy storage battery unit, and sends it to the high-performance control stage of the three-phase dual active full-bridge DC / DC converter.

3. The high-performance control method for a bipolar energy storage converter according to claim 1, characterized in that: The high-performance control of the three-phase dual active full-bridge DC / DC converter includes: Step 201. Set the operating power value of the three-phase dual active full-bridge DC / DC converter according to the superior dispatch instruction; Step 202. Based on the energy storage battery cell status identified by the SOC of the energy storage battery cell, select the high-performance control mode of the three-phase dual active full-bridge DC / DC converter according to the range of the operating power value; the high-performance control mode of the converter includes three-phase mode, single-phase high-power mode and single-phase low-power mode. Step 203. The three-phase dual active full-bridge DC / DC converter generates the phase shift duty cycle under the corresponding control mode based on the high-performance control mode of the three-phase dual active full-bridge DC / DC converter. Step 204. Based on the generated phase shift duty cycle, the PWM modulation stage generates PWM trigger pulses for the six bridge arms of the three-phase dual active full-bridge DC / DC converter to drive the converter to operate at high performance.

4. The high-performance control method for a bipolar energy storage converter according to claim 1, characterized in that: The AC grid voltage phase-locked loop uses a SOGI-PLL single-phase phase-locked loop to calculate the active phase of the AC grid and output it to the grid-connected converter grid-connected control loop.

5. The high-performance control method for a bipolar energy storage converter according to claim 1, characterized in that: The grid-connected converter grid-connection control circuit includes: Step 301. Collect the DC regulated capacitor voltage and grid-connected current; Step 302. Set the voltage setpoint for the DC regulated capacitor; Step 303. The difference between the DC regulated capacitor voltage value and the given value is used to generate the grid-connected current amplitude given value through the DC voltage control outer loop; Step 304. Multiply the given value of the grid-connected current amplitude by the active phase of the AC grid, and then subtract the difference from the grid-connected current. This difference is then used to generate an SPWM modulation wave through the AC current control inner loop for modulation of the grid-connected converter. Step 305. Generate drive pulse signals for the four switching transistors of the grid-connected converter to drive the converter to operate in grid-connected mode.

6. A computer device comprising a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the high-performance control method for a bipolar energy storage converter as described in any one of claims 1-5.

7. A computer storage medium, characterized in that: The computer storage medium contains a computer program, which, when executed by a processor, implements the steps of a high-performance control method for a bipolar energy storage converter as described in any one of claims 1-5.

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