A control method of an energy storage converter

Abstract

The application discloses a kind of energy storage converters, the energy storage converter includes several bridge arms, capacity capacitor C1, capacity capacitor C2, and several The bridge arm includes upper half bridge arm and lower half bridge arm, the upper half bridge arm and lower half bridge arm include N power unit and reactor, N The power unit includes all-controlled power semiconductor device Q1, all-controlled power semiconductor device Q2, all-controlled power semiconductor device Q3, all-controlled power semiconductor device Q4 and capacity capacitor C.This energy storage converter control method and energy storage converter, by the technical structure and disclosed energy storage converter control method of setting in energy storage converter, further can realize direct current 0~1500 volts, alternating current 0~1000 volts under the architecture of single-stage power converter, transformerless, by which can satisfy different voltage grade low-voltage alternating current system Direct access while providing favorable conditions for solving various fault ride-through and other abnormal conditions.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemical energy storage, in particular to a control method of an energy storage converter. BACKGROUND

[0002] As one of the devices capable of controlling the charging and discharging process of the battery and converting AC and DC, the energy storage converter can directly power the AC load without power grid. In order to adapt to the application requirements of different electrochemical energy storage batteries, the energy storage converter of the existing electrochemical energy storage system needs to ensure a very wide DC voltage range. In order to meet the direct access of different voltage level low voltage AC systems and provide solutions for various fault ride-through and abnormal conditions, it also needs to have an extremely wide AC voltage range.

[0003] In the prior art, in order to meet the above requirements, two-stage power converter architecture or transformer is usually used to achieve it. Although it can meet the basic use requirements, due to the increase of the number of devices and the extension of the specific conversion process, the use cost is increased and the conversion efficiency is reduced in the actual application process, which leads to obvious inequality between the benefits and the cost. Therefore, the above-mentioned defects of the prior art are solved by providing a control method of an energy storage converter. SUMMARY

[0004] (I) Technical problems to be solved

[0005] In view of the defects of the prior art, the present application provides a control method of an energy storage converter, which solves the problems in the background art.

[0006] (II) Technical scheme

[0007] In order to achieve the above-mentioned purpose, the present application provides the following technical scheme: an energy storage converter, the energy storage converter comprises a plurality of bridge arms, a capacity capacitor C1 and a capacity capacitor C2, and each of the plurality of bridge arms comprises an upper half bridge arm and a lower half bridge arm, the upper half bridge arm and the lower half bridge arm each comprise N power units and a reactor.

[0008] Each of the N power units comprises a fully controlled power semiconductor device Q1, a fully controlled power semiconductor device Q2, a fully controlled power semiconductor device Q3, a fully controlled power semiconductor device Q4 and a capacity capacitor C.

[0009] Preferably, the number of the plurality of bridge arms is three, and the three bridge arms are respectively connected with a phase line A, a phase line B and a phase line C between the corresponding power grid.

[0010] Preferably, the upper half bridge arm is connected between the DC positive and the AC phase line, and the lower half bridge arm is connected between the DC negative and the AC phase line.

[0011] Preferably, N is a natural number, and N is not less than 2.

[0012] Preferably, the connecting point of the fully-controlled power semiconductor device Q1 and the fully-controlled power semiconductor device Q3 is an external connecting point T1 of the power unit;

[0013] The connecting point of the fully-controlled power semiconductor device Q2 and the fully-controlled power semiconductor device Q4 is an external connecting point T2 of the power unit;

[0014] The fully-controlled power semiconductor device Q1 is connected between the positive electrode of the capacitor and T1, and the fully-controlled power semiconductor device Q2 is connected between the positive electrode of the capacitor and T2;

[0015] The fully-controlled power semiconductor device Q3 is connected between the negative electrode of the capacitor and T1, and the fully-controlled power semiconductor device Q4 is connected between the negative electrode of the capacitor and T2.

[0016] Preferably, the working voltage between the capacitors of the N power units is Uc, and the DC voltage range of the energy storage converter is 0~N•Uc, and the AC voltage range is 0~N•Uc. .

[0017] Preferably, the energy storage converter is connected to a three-phase four-wire power grid, and a neutral line D is led out at the connecting point of the capacity capacitor C1 and the capacity capacitor C2.

[0018] Preferably, the energy storage converter is connected to a three-phase three-wire power grid, and a neutral line D is not led out at the connecting point of the capacity capacitor C1 and the capacity capacitor C2.

[0019] Preferably, the control method of the energy storage converter comprises the following steps:

[0020] S1, by calculating the capacitor voltage of all power units of each bridge arm, the instruction value of the current sum of the upper and lower half-bridge arms of each bridge arm is obtained, and the more specific operation is as follows:

[0021] (1) measure the voltage of the capacitor of each power unit;

[0022] (2) sum the capacitor voltages of all power units of each bridge arm respectively;

[0023] (3) difference between the sum of the capacitor voltages of all power units of each bridge arm and the set value of the sum of the capacitor voltages of each bridge arm power unit, and proportional integral regulator is performed on the difference, to obtain the instruction value of the current sum of the upper and lower half-bridge arms of each bridge arm;

[0024] S2, divide the active power and reactive power instruction of each phase issued by the upper control unit by the corresponding phase alternating current voltage, and then obtain the active current instruction and the reactive current instruction of each phase. The active current instruction and the reactive current instruction are respectively converted by rotating coordinate transformation and added, and then the instantaneous value of the output current instruction of each phase, that is, the instruction value of the current difference of the upper and lower two half-bridge arms of each bridge arm, is obtained;

[0025] S3, by calculating the current of the upper and lower two half-bridge arms of each bridge arm, the instruction value of the sum of the output voltages of the upper and lower two half-bridge arms of each bridge arm and the instruction value of the difference of the output voltages of the upper and lower two half-bridge arms of each bridge arm are obtained, and the specific operation is as follows:

[0026] (1) measure the current of the upper and lower two half-bridge arms of each bridge arm;

[0027] (2) calculate the measured value of the sum of the currents of the upper and lower two half-bridge arms of each bridge arm;

[0028] (3) calculate the measured value of the difference of the currents of the upper and lower two half-bridge arms of each bridge arm;

[0029] (4) subtract the instruction value of the sum of the currents of the upper and lower two half-bridge arms of each bridge arm from the measured value, and perform proportional integral regulator on the difference to obtain the instruction value of the sum of the output voltages of the upper and lower two half-bridge arms of each bridge arm;

[0030] (5) subtract the instruction value of the difference of the currents of the upper and lower two half-bridge arms of each bridge arm from the measured value, and perform proportional second-order generalized integral regulator on the difference to obtain the instruction value of the difference of the output voltages of the upper and lower two half-bridge arms of each bridge arm;

[0031] S4, add the instruction value of the sum of the output voltages of the upper and lower two half-bridge arms of each bridge arm to the instruction value of the difference of the output voltages of the upper and lower two half-bridge arms of each bridge arm, and then divide by two to obtain the output voltage instruction value of the upper half-bridge arm of each bridge arm;

[0032] S5, subtract the instruction value of the sum of the output voltages of the upper and lower two half-bridge arms of each bridge arm from the instruction value of the difference of the output voltages of the upper and lower two half-bridge arms of each bridge arm, and then divide by two to obtain the output voltage instruction value of the lower half-bridge arm of each bridge arm;

[0033] S6, divide the output voltage of each half-bridge arm by the number N of power units contained in each half-bridge arm to obtain the instruction value of the output voltage of each power unit;

[0034] S7, divide the output voltage of each power unit by the direct current voltage of each power unit to obtain the duty cycle instruction value of each power unit;

[0035] S8, the voltage of each power unit capacitor is subtracted from the average value of the voltage of each power unit capacitor of the same bridge arm, and the required capacitor voltage balance current instruction is obtained through a proportional regulator, and then divided by the current measured value flowing through the power unit to obtain the correction value of the duty cycle instruction of each power unit;

[0036] S9, the duty cycle instruction value of each power unit is added to the correction value of the duty cycle instruction of each power unit to obtain the modulation wave value of the pulse width modulation of the power unit Q1, and the negative value is obtained as the modulation wave value of the pulse width modulation of Q2, and the action signal of Q1 and Q2 is obtained by comparing with the carrier value, and the action signal of Q1 is inverted and added to the dead zone as the action signal of Q3, and the action signal of Q2 is inverted and added to the dead zone as the action signal of Q4;

[0037] S10, the carrier phases of the power units of the same bridge arm are π / 2N apart to form a carrier phase-shifted multi-level modulation.

[0038] (Three) beneficial effects

[0039] The application provides a control method of an energy storage converter, which has the following beneficial effects:

[0040] (1) The control method of the energy storage converter, through the technical structure arranged in the energy storage converter and the disclosed control method of the energy storage converter, can realize a very wide voltage of DC 0-1500V and AC 0-1000V under the architecture of a single-stage power converter and a transformerless structure, thereby being able to meet the direct access of different voltage grade low-voltage AC systems and provide favorable conditions for solving various fault ride-through and abnormal conditions, and thereby adapting to the application requirements of different electrochemical energy storage batteries, and the electrochemical energy storage batteries include lithium ion batteries, sodium ion batteries, flow batteries and super capacitors.

[0041] (2) The control method of the energy storage converter, after the energy storage converter is combined with a suitable three-phase four-wire power grid, the three-phase four-wire power grid provides a phase voltage between phase lines and a neutral line D, which is usually 220V, and the introduction of the neutral line D provides power for single-phase loads, and a complete circuit is formed between each phase line and the neutral line D, which makes the three-phase four-wire power grid particularly suitable for the energy storage converter circuit system, and can efficiently output power to three-phase and single-phase loads at the same time.

[0042] (3) The control method of the energy storage converter, after the energy storage converter is combined with a suitable three-phase four-wire power grid, the three-phase three-wire power grid can not introduce the neutral line D, and the three transmission lines are spaced 120 degrees apart in phase angle, so that the load current can still be balanced without a neutral point, and if the load is completely balanced, the current at the neutral point is theoretically zero, so there is no need for the neutral line D, thereby creating favorable conditions for optimizing the use cost of the energy storage converter. Attached Figure Description

[0043] Figure 1 This is a circuit diagram of a first embodiment of the structure of the present invention;

[0044] Figure 2 This is a circuit diagram of a second embodiment of the structure of the present invention;

[0045] Figure 3 This is a circuit diagram of the power unit structure of the present invention. Detailed Implementation

[0046] Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] Example 1

[0048] Please see Figure 1 An energy storage converter includes several bridge arms, a capacity capacitor C1, a capacity capacitor C2, and each of the several bridge arms includes an upper bridge arm and a lower bridge arm, and each of the upper bridge arm and the lower bridge arm includes N power units and reactors.

[0049] Each of the N power units includes a fully controlled power semiconductor device Q1, a fully controlled power semiconductor device Q2, a fully controlled power semiconductor device Q3, a fully controlled power semiconductor device Q4, and a capacitor C. The operating voltage across the capacitors of all N power units is Uc. The DC voltage range of this energy storage converter is 0 to N•Uc, and the AC voltage range is 0 to N•Uc / N is a natural number and is not less than 2.

[0050] The connection point of the fully controlled power semiconductor device Q1 and the fully controlled power semiconductor device Q3 is the external connection point T1 of the power unit. The connection point of the fully controlled power semiconductor device Q2 and the fully controlled power semiconductor device Q4 is the external connection point T2 of the power unit. The fully controlled power semiconductor device Q1 is connected between the positive terminal of the capacitor and T1. The fully controlled power semiconductor device Q2 is connected between the positive terminal of the capacitor and T2. The fully controlled power semiconductor device Q3 is connected between the negative terminal of the capacitor and T1. The fully controlled power semiconductor device Q4 is connected between the negative terminal of the capacitor and T2.

[0051] The number of the bridge arms is three, and the three bridge arms are connected with phase line A, phase line B and phase line C respectively between the corresponding power grid, the upper half bridge arm is connected between the direct current positive and the alternating current phase line, and the lower half bridge arm is connected between the direct current negative and the alternating current phase line, and the energy storage converter is connected with a three-phase four-wire power grid and a neutral line D is led out at the connection point of the capacity capacitor C1 and the capacity capacitor C2.

[0052] In use, the three-phase four-wire power grid used by the energy storage converter includes four wires, namely three phase lines (L1, L2 and L3) and a neutral line D. In addition to the line voltage (usually 380V) between the phase lines, the three-phase four-wire power grid also provides a phase voltage between the phase lines and the neutral line D, which is usually 220V. The introduction of the neutral line D provides power for single-phase loads, and a complete circuit is formed between each phase line and the neutral line D, which makes the three-phase four-wire power grid particularly suitable for the energy storage converter circuit system, which can efficiently supply power to three-phase and single-phase loads at the same time.

[0053] Please refer to Figure 2 The energy storage converter is connected with a three-phase three-wire power grid, and a neutral line D is not led out at the connection point of the capacity capacitor C1 and the capacity capacitor C2.

[0054] In use, the three-phase three-wire power grid used by the energy storage converter is mainly composed of three wires, and the voltage between the three phase lines is called line voltage, which is usually 380V or other standard range in industrial applications. The three-phase three-wire power grid does not lead out a neutral line D, and the three transmission lines are spaced 120 degrees apart in phase angle, so that the load current can still be balanced without a neutral point. Moreover, if the load is completely balanced, the current at the neutral point is theoretically zero, so there is no need for a neutral line D. Therefore, this can create favorable conditions for the optimization of the use cost of the energy storage converter.

[0055] Embodiment two

[0056] Please refer to Figure 1 , Figure 3 The control method of the energy storage converter includes the following steps:

[0057] S1, by calculating the capacitor voltage of all power units of each bridge arm, the instruction value of the current sum of the upper and lower half bridge arms of each bridge arm is obtained, and the more specific operation is as follows:

[0058] (1) measure the voltage of the capacitor of each power unit;

[0059] (2) sum the capacitor voltages of all power units of each bridge arm respectively;

[0060] (3) the sum of the capacitor voltages of all power units in each bridge arm is subtracted from the set value of the sum of the capacitor voltages of each bridge arm power unit, and the difference is subjected to proportional integral adjustment, to obtain the instruction value of the sum of the currents of the upper and lower half-bridge arms of each bridge arm;

[0061] S2, the active power and reactive power instructions of each phase issued by the upper control unit are divided by the corresponding phase alternating current voltage, and then the active current instruction and the reactive current instruction of each phase are obtained. The active current instruction and the reactive current instruction are respectively subjected to rotating coordinate transformation and addition, and then the instantaneous value of the output current instruction of each phase, that is, the instruction value of the current difference of the upper and lower half-bridge arms of each bridge arm, is obtained;

[0062] S3, through the calculation of the currents of the upper and lower half-bridge arms of each bridge arm, the instruction value of the sum of the output voltages of the upper and lower half-bridge arms of each bridge arm and the instruction value of the difference of the output voltages of the upper and lower half-bridge arms of each bridge arm are obtained, and the more specific operation is as follows:

[0063] (1) the currents of the upper and lower half-bridge arms of each bridge arm are measured;

[0064] (2) the measurement value of the sum of the currents of the upper and lower half-bridge arms of each bridge arm is calculated;

[0065] (3) the measurement value of the difference of the currents of the upper and lower half-bridge arms of each bridge arm is calculated;

[0066] (4) the instruction value of the sum of the currents of the upper and lower half-bridge arms of each bridge arm is subtracted from the measurement value, and the difference is subjected to proportional integral adjustment, to obtain the instruction value of the sum of the output voltages of the upper and lower half-bridge arms of each bridge arm;

[0067] (5) the instruction value of the difference of the currents of the upper and lower half-bridge arms of each bridge arm is subtracted from the measurement value, and the difference is subjected to proportional second-order generalized integral adjustment, to obtain the instruction value of the difference of the output voltages of the upper and lower half-bridge arms of each bridge arm;

[0068] S4, the instruction value of the sum of the output voltages of the upper and lower half-bridge arms of each bridge arm is added to the instruction value of the difference of the output voltages of the upper and lower half-bridge arms of each bridge arm, and then divided by two, to obtain the output voltage instruction value of the upper half-bridge arm of each bridge arm;

[0069] S5, the instruction value of the sum of the output voltages of the upper and lower half-bridge arms of each bridge arm is subtracted from the instruction value of the difference of the output voltages of the upper and lower half-bridge arms of each bridge arm, and then divided by two, to obtain the output voltage instruction value of the lower half-bridge arm of each bridge arm;

[0070] S6, the output voltage of each half-bridge arm is divided by the number N of power units contained in each half-bridge arm, to obtain the instruction value of the output voltage of each power unit;

[0071] S7, divide the output voltage of each power unit by the DC voltage of each power unit to obtain the duty cycle command value of each power unit;

[0072] S8, subtract the voltage of each power unit capacitor from the average value of the voltage of each power unit capacitor of the same bridge arm, pass through a proportional regulator to obtain the current command required for capacitor voltage balance, and then divide the measured current flowing through the power unit to obtain the correction value of the duty cycle command of each power unit;

[0073] S9, add the duty cycle command value of each power unit to the correction value of the duty cycle command of each power unit to obtain the modulation wave value of the pulse width modulation of the power unit Q1, take the negative to obtain the modulation wave value of the pulse width modulation of Q2, compare with the carrier value to obtain the action signal of Q1 and Q2, take the inverse of the Q1 action signal and add a dead zone as the action signal of Q3, and take the inverse of the Q2 action signal and add a dead zone as the action signal of Q4;

[0074] S10, the carrier phases of the power units of the same bridge arm are π / 2N apart to form a carrier phase-shifted multi-level modulation.

[0075] In summary, the energy storage converter control method, through the above disclosed technical structure and the control method of the energy storage converter, can realize a very wide voltage of DC 0-1500V and AC 0-1000V under the architecture of single-stage power converter and transformerless, thereby being able to meet the direct access of different voltage grade low-voltage AC systems and provide favorable conditions for various fault ride-through and other abnormal conditions, and further adapt to the application requirements of different electrochemical energy storage batteries, and the electrochemical energy storage batteries include lithium ion batteries, sodium ion batteries, flow batteries, and super capacitors.

[0076] It should be noted that in this text, relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device.

[0077] Although embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A control method of an energy storage converter, comprising an energy storage converter, the energy storage converter comprising a plurality of bridge arms, a capacity capacitor C1, a capacity capacitor C2, and each of the plurality of bridge arms comprising an upper half bridge arm and a lower half bridge arm, each of the upper half bridge arm and the lower half bridge arm comprising N power units and a reactor; each of the N power units comprising a fully-controlled power semiconductor device Q1, a fully-controlled power semiconductor device Q2, a fully-controlled power semiconductor device Q3, a fully-controlled power semiconductor device Q4, and a capacity capacitor C; The control method of the energy storage converter is characterized in that, comprising the following operation steps: S1, obtaining the instruction value of the sum of the currents of the upper and lower half bridge arms of each bridge arm through the calculation of the capacity voltage of all power units for each bridge arm; S2, dividing the active power and reactive power instructions of each phase issued by the upper control unit by the corresponding phase alternating current voltage to obtain the active current instruction and the reactive current instruction of each phase, and adding the active current instruction and the reactive current instruction through rotation coordinate transformation to obtain the instantaneous value of the output current instruction of each phase, that is, the instruction value of the current difference of the upper and lower half bridge arms of each bridge arm; S3, obtaining the instruction value of the sum of the output voltages of the upper and lower half bridge arms of each bridge arm and the instruction value of the output voltage difference of the upper and lower half bridge arms of each bridge arm through the calculation of the currents of the upper and lower half bridge arms of each bridge arm; S4, adding the instruction value of the sum of the output voltages of the upper and lower half bridge arms of each bridge arm and the instruction value of the output voltage difference of the upper and lower half bridge arms of each bridge arm and dividing by two to obtain the output voltage instruction value of the upper half bridge arm of each bridge arm; S5, subtracting the instruction value of the sum of the output voltages of the upper and lower half bridge arms of each bridge arm from the instruction value of the output voltage difference of the upper and lower half bridge arms of each bridge arm and dividing by two to obtain the output voltage instruction value of the lower half bridge arm of each bridge arm; S6, dividing the output voltage of each half bridge arm by the number N of power units contained in each half bridge arm to obtain the instruction value of the output voltage of each power unit; S7, dividing the output voltage of each power unit by the direct current voltage of each power unit to obtain the duty cycle instruction value of each power unit; S8, subtracting the average value of the capacitor voltages of each power unit in the same bridge arm from the capacitor voltage of each power unit, passing through a proportional regulator to obtain the current instruction required for capacitor voltage balance, and then dividing by the measured value of the current flowing through the power unit to obtain the correction value of the duty cycle instruction of each power unit; S9, adding the duty cycle instruction value of each power unit to the correction value of the duty cycle instruction of each power unit to obtain the modulation wave value of the pulse width modulation of the power unit Q1, taking the negative to obtain the modulation wave value of the pulse width modulation of Q2, and comparing with the carrier value to obtain the action signals of Q1 and Q2, taking the inverse of the Q1 action signal and adding a dead zone as the action signal of Q3, and taking the inverse of the Q2 action signal and adding a dead zone as the action signal of Q4; S10, the carrier phases of the power units in the same bridge arm are π / 2N apart to form a carrier phase-shifted multi-level modulation.

2. The control method of the energy storage converter according to claim 1, characterized in that: The number of the plurality of bridge arms is three, and each of the three bridge arms is connected with a phase line A, a phase line B, and a phase line C corresponding to the power grid.

3. The control method of the energy storage converter according to claim 1, characterized in that: The upper half bridge arm is connected between a direct current positive and an alternating current phase line, and the lower half bridge arm is connected between a direct current negative and an alternating current phase line.

4. The control method of the energy storage converter according to claim 1, characterized in that: The N is a natural number, and N is not less than 2.

5. The control method of the energy storage converter according to claim 1, characterized in that: The connection point of the fully-controlled power semiconductor device Q1 and the fully-controlled power semiconductor device Q3 is an external connection point T1 of the power unit; The connection point of the fully-controlled power semiconductor device Q2 and the fully-controlled power semiconductor device Q4 is an external connection point T2 of the power unit; The fully-controlled power semiconductor device Q1 is connected between a capacitor positive and T1, and the fully-controlled power semiconductor device Q2 is connected between a capacitor positive and T2; The fully-controlled power semiconductor device Q3 is connected between a capacitor negative and T1, and the fully-controlled power semiconductor device Q4 is connected between a capacitor negative and T2.

6. The control method of an energy storage inverter according to claim 1, characterized by: The working voltage between the capacitances of N power units is Uc, the DC voltage range of the energy storage converter is 0~N•Uc, and the AC voltage range is 0~N•Uc .

7. The control method of an energy storage inverter according to claim 1, characterized by: The energy storage converter is connected to a three-phase four-wire power grid and a neutral line D is led out at the connection point of the capacity capacitor C1 and the capacity capacitor C2.

8. The control method of the energy storage converter according to claim 1, characterized in that: The energy storage converter is connected to a three-phase three-wire power grid, and a neutral line D does not need to be led out at the connection point of the capacity capacitor C1 and the capacity capacitor C2.

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