CN106549407A - The control method and equipment of the super capacitor in micro-capacitance sensor - Google Patents

Abstract

The present invention provides a control method and equipment for a supercapacitor in a microgrid. The control method for the supercapacitor includes: a detection unit detects the real-time voltage and real-time current of the bus bar of the microgrid; a real-time power calculation unit based on the real-time voltage and the real-time current The real-time current calculates the active power and reactive power; the discharge control unit controls the discharge of the supercapacitor according to the active power and the reactive power, so as to adjust the voltage of the microgrid bus. Using the supercapacitor control method in the microgrid according to the exemplary embodiment of the present invention to control the supercapacitor can give full play to the advantages of the fast start of the supercapacitor, and when the microgrid fluctuates, the bus voltage can be quickly returned to normal, which can be compared Greatly improve power quality.

Description

Control method and device for supercapacitor in microgrid

technical field

The present invention relates to the field of micro-grid control, in particular to a control method and equipment for a supercapacitor in a micro-grid.

Background technique

At present, both at home and abroad are committed to the construction of micro-grids, and to improve and solve the power quality problems generated in the process of micro-grids. As a power-type energy storage technology, supercapacitors can stabilize transient fluctuations, improve power quality, and provide short-term energy, which plays a very important role in stabilizing microgrids.

A supercapacitor is an electrochemical component. There is no chemical reaction in the energy storage process, and the energy storage process is reversible. Therefore, the supercapacitor can be repeatedly charged and discharged hundreds of thousands of times, with a life span of more than 10 years, and will not cause environmental pollution. pollute. In addition, it has a very high power density, which is 10 to 100 times that of the battery, suitable for short-term high power output, fast charging speed, simple mode, can be charged with high current, and can be charged within tens of seconds to minutes The process is fast charging in the true sense. The electrochemical reaction that occurs during the charge and discharge process has good reversibility, and the low temperature performance is excellent. Most of the charge transfer that occurs during the charge and discharge process of the supercapacitor is carried out on the surface of the electrode active material, and the capacity decay with temperature is very small.

The control strategies currently applied to supercapacitors do not play an ideal role in improving power quality.

Contents of the invention

The purpose of the present invention is to provide a control method and equipment for supercapacitors in a microgrid, so as to solve the technical problem that the existing control strategy does not play an ideal role in improving power quality.

According to the first aspect of the present invention, there is provided a control method of a supercapacitor in a microgrid, the control method of the supercapacitor includes: a detection unit detects the real-time voltage and real-time current of the microgrid bus; the real-time power calculation unit is based on the The real-time voltage and the real-time current calculate active power and reactive power; the discharge control unit controls the discharge of the supercapacitor according to the active power and the reactive power, so as to adjust the voltage of the microgrid bus.

Optionally, the step of controlling the discharge of the supercapacitor includes: the phase angle calculation unit calculates the phase angle of the supercapacitor output voltage according to the active power, the given active power, and the rated frequency of the microgrid; the voltage amplitude calculation unit calculates the phase angle of the output voltage of the supercapacitor according to the The reactive power, the given reactive power, and the rated voltage of the microgrid calculate the amplitude of the output voltage of the supercapacitor; the discharge control unit controls the discharge of the supercapacitor according to the calculated phase angle and amplitude of the output voltage of the supercapacitor to adjust the microgrid. The voltage of the grid bus.

Optionally, the step of calculating the phase angle of the output voltage of the supercapacitor includes: the phase angle calculation unit calculates the frequency droop coefficient according to the active power, the given active power and the rated frequency of the microgrid, and calculates the frequency droop coefficient according to the calculated frequency droop coefficient and Calculate the phase angle of the supercapacitor output voltage for the rated frequency of the microgrid.

Optionally, the step of calculating the magnitude of the output voltage of the supercapacitor includes: the voltage magnitude calculation unit calculates the voltage droop coefficient according to the reactive power, the given reactive power and the rated voltage of the microgrid, and according to the calculated voltage The droop coefficient and the rated voltage of the microgrid are used to calculate the magnitude of the output voltage of the supercapacitor.

Optionally, the step of controlling the discharge of the supercapacitor according to the calculated phase angle and amplitude of the output voltage of the supercapacitor to adjust the voltage of the microgrid bus includes: the voltage reference calculation unit based on the phase angle and amplitude of the output voltage of the supercapacitor Calculate the d-axis reference voltage and the q-axis reference voltage; the discharge control unit calculates the positive voltage of the space vector pulse width modulation according to the d-axis reference voltage and the d-axis positive sequence voltage feedback and the q-axis reference voltage and the q-axis positive sequence voltage feedback sequence component, so that the positive sequence component of the voltage of the microgrid bus is within the rated range, the d-axis positive sequence voltage feedback and the q-axis positive sequence voltage feedback are obtained by extracting the positive and negative sequences of the real-time voltage positive sequence component; the discharge control unit calculates the negative sequence component of the space vector pulse width modulation according to the d-axis negative sequence voltage feedback and the q-axis negative sequence voltage feedback, which is used to compensate the voltage of the microgrid busbar and eliminate the voltage of the microgrid busbar The negative-sequence component, the d-axis negative-sequence voltage feedback and the q-axis negative-sequence voltage feedback are negative-sequence components obtained by extracting positive and negative sequences from the real-time voltage.

Optionally, the step of calculating active power and reactive power includes: the real-time power calculation unit performs Clarke coordinate axis conversion and Parker coordinate axis conversion on the real-time voltage and the real-time current, and converts the real-time voltage and the real-time current according to the Clarke coordinate axis conversion and Parker coordinate axis conversion. The converted real-time voltage and real-time current calculate the active power and the reactive power.

Optionally, the control method of the supercapacitor further includes: the detection unit detects whether the stored charge of the supercapacitor is less than a predetermined value; when the charge stored in the supercapacitor is less than the predetermined value, the control unit controls the supercapacitor to stop discharging ; When the charge stored in the supercapacitor is greater than the predetermined value, return to the detection unit to perform the step of detecting the real-time voltage and real-time current of the bus bar of the microgrid.

According to another aspect of the present invention, there is provided a supercapacitor control device, the supercapacitor control device includes: a detection unit, which detects the real-time voltage and real-time current of the busbar of the microgrid; a real-time power calculation unit, based on the real-time voltage and The real-time current calculates active power and reactive power; the discharge control unit controls the discharge of the supercapacitor according to the active power and the reactive power, so as to adjust the voltage of the microgrid bus.

Optionally, the discharge control unit includes: a phase angle calculation unit, which calculates the phase angle of the output voltage of the supercapacitor according to the active power, the given active power, and the rated frequency of the microgrid; Calculate the magnitude of the output voltage of the supercapacitor based on the active power, the given reactive power and the rated voltage of the microgrid; wherein, the discharge control unit controls the discharge of the supercapacitor according to the calculated phase angle and magnitude of the output voltage of the supercapacitor to adjust The voltage of the microgrid bus.

Optionally, the phase angle calculation unit calculates the frequency droop coefficient according to the active power, the given active power and the rated frequency of the microgrid, and calculates the phase angle of the output voltage of the supercapacitor according to the calculated frequency droop coefficient and the rated frequency of the microgrid. horn.

Optionally, the voltage amplitude calculation unit calculates the voltage droop coefficient according to the reactive power, the given reactive power and the rated voltage of the microgrid, and calculates the supercapacitor output according to the calculated voltage droop coefficient and the rated voltage of the microgrid magnitude of the voltage.

Optionally, the discharge control unit further includes: a voltage reference calculation unit, which calculates a d-axis reference voltage and a q-axis reference voltage based on the phase angle and amplitude of the output voltage of the supercapacitor; wherein, the discharge control unit calculates the d-axis reference voltage based on the d-axis reference voltage and d-axis positive-sequence voltage feedback and the q-axis reference voltage and q-axis positive-sequence voltage feedback to calculate the positive-sequence component of space vector pulse width modulation, so that the positive-sequence component of the voltage of the microgrid bus is within the rated range, so The d-axis positive-sequence voltage feedback and the q-axis positive-sequence voltage feedback are positive-sequence components obtained by extracting the positive and negative sequences of the real-time voltage; the discharge control unit Feedback calculates the negative sequence component of the space vector pulse width modulation for compensating the voltage of the microgrid bus and eliminating the negative sequence component of the voltage of the microgrid bus, the d-axis negative sequence voltage feedback and the q axis negative sequence voltage feedback is the negative sequence component obtained by extracting the positive and negative sequences of the real-time voltage.

Optionally, the real-time power calculation unit performs Clark coordinate axis transformation and Park coordinate axis transformation on the real-time voltage and the real-time current, and calculates the real-time voltage and current according to the real-time voltage and real-time current after Clark coordinate axis transformation and Park coordinate axis transformation. active power and the reactive power.

Optionally, the detection unit also detects whether the amount of charge stored in the supercapacitor is less than a predetermined value; when the amount of charge stored in the supercapacitor is less than the predetermined value, the control unit controls the supercapacitor to stop discharging; when the amount of charge stored in the supercapacitor is greater than When the predetermined value is reached, the detection unit continues to detect the real-time voltage and real-time current of the bus bar of the microgrid.

Using the supercapacitor control method in the microgrid according to the exemplary embodiment of the present invention to control the supercapacitor can give full play to the advantages of the fast start of the supercapacitor, and when the microgrid fluctuates, the bus voltage can be quickly returned to normal, which can be compared Greatly improve power quality.

In addition, according to the supercapacitor control method in the microgrid of the exemplary embodiment of the present invention to control the supercapacitor, the supercapacitor controller has a plug-and-play function, and only needs to change the supercapacitor according to the voltage and frequency changes on the bus Its own power output to stabilize bus voltage and frequency.

In addition, the supercapacitor is controlled according to the supercapacitor control method in the microgrid according to the exemplary embodiment of the present invention, because the supercapacitor does not communicate with the rest of the distributed power sources, which saves the communication time and does not collect the information of the other main power sources. The power output saves the acquisition and calculation time of nearly one cycle, which can be faster than the current supercapacitor control method.

In addition, controlling the supercapacitor according to the supercapacitor control method in the microgrid according to the exemplary embodiment of the present invention can allow the supercapacitor to enter the linear operation region by setting a reasonable droop coefficient.

Additional aspects and/or advantages of the present invention will be set forth in part in the following description, and some will be clear from the description, or can be learned through practice of the present invention.

Description of drawings

The above-mentioned and other objects, features and advantages of the present invention will become more clear through the following detailed description in conjunction with the accompanying drawings, wherein:

1 is a block diagram of a control device for a supercapacitor of a microgrid according to an exemplary embodiment of the present invention;

2 is a flowchart of a method for controlling a supercapacitor in a microgrid according to an exemplary embodiment of the present invention;

FIG. 3 is a block diagram of a real-time power calculation unit of a supercapacitor control device according to an exemplary embodiment of the present invention;

4 is a schematic graph of voltage droop control according to an exemplary embodiment of the present invention;

5 is a schematic graph of frequency droop control according to an exemplary embodiment of the present invention;

6 is a block diagram of a phase angle calculation unit of a supercapacitor control device according to an exemplary embodiment of the present invention;

7 is a block diagram of a voltage amplitude calculation unit of a supercapacitor control device according to an exemplary embodiment of the present invention;

8 is a block diagram of a voltage reference calculation unit of a control device for a supercapacitor according to an exemplary embodiment of the present invention;

9 is a block diagram of a positive sequence voltage outer loop and current inner loop dual-loop control strategy according to an exemplary embodiment of the present invention;

Fig. 10 is a block diagram of a dual-loop control strategy of negative sequence voltage outer loop and current inner loop according to an exemplary embodiment of the present invention;

11 is a structural block diagram of a microgrid according to an exemplary embodiment of the present invention;

Fig. 12 is a current transient curve diagram during a sensitive load cut-in process according to an exemplary embodiment of the present invention;

Fig. 13 is a graph of voltage transients during a sensitive load cut-in process according to an exemplary embodiment of the present invention.

detailed description

As required, detailed embodiments of the invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

Fig. 1 shows a block diagram of a control device for a supercapacitor in a microgrid according to an exemplary embodiment of the present invention. As shown in FIG. 1 , a control device for a supercapacitor in a microgrid according to an exemplary embodiment of the present invention includes a detection unit 101 , a real-time power calculation unit 102 , and a discharge control unit 103 .

The detection unit 101 detects the real-time voltage and real-time current of the microgrid bus. The real-time power calculation unit 102 calculates active power and reactive power based on the real-time voltage and the real-time current. The discharge control unit 103 controls the discharge of the supercapacitor according to the active power and the reactive power, so as to adjust the voltage of the microgrid bus. The discharge control unit 103 may include a phase angle calculation unit, a voltage amplitude calculation unit, and a reference voltage value calculation unit.

Each unit included in the supercapacitor control device in the microgrid according to an exemplary embodiment of the present invention will be described in detail below with reference to FIGS. 2 to 10 .

Fig. 2 is a flowchart of a method for controlling a supercapacitor in a microgrid according to an exemplary embodiment of the present invention.

As shown in FIG. 2 , in step S201 , the detection unit 101 detects the real-time voltage and real-time current of the microgrid bus.

In step S202, the real-time power calculation unit 102 calculates active power and reactive power based on the real-time voltage and the real-time current.

FIG. 3 is a block diagram of the real-time power calculation unit 102 according to an exemplary embodiment of the present invention. In step S202, the real-time power calculation unit 102 performs Clark coordinate axis conversion and Park coordinate axis conversion respectively on the real-time voltage value and real-time current value, and then calculates the active power on the microgrid bus according to the real-time voltage value and real-time current value after coordinate axis conversion power and reactive power.

In step S203, the discharge control unit 103 controls the discharge of the supercapacitor according to the active power and the reactive power, so as to adjust the voltage of the microgrid bus.

In step S203, droop control may be used to control the supercapacitor, so as to compensate the voltage of the microgrid bus.

FIG. 4 is a schematic graph of voltage droop control according to an exemplary embodiment of the present invention. FIG. 5 is a schematic graph of frequency droop control according to an exemplary embodiment of the present invention.

As shown in FIG. 4 , when the bus voltage is higher than the standard value (namely, the rated voltage) V ₀ , the supercapacitor can absorb reactive power, thereby reducing the voltage to the standard value V ₀ . When the bus voltage is lower than the standard value V ₀ , the supercapacitor can generate reactive power, thereby increasing the voltage to the standard value V ₀ .

If the microgrid system fails and the voltage drops to V ₁ instantaneously, the operating state of the system will slide from point A to point B, and more reactive power will be generated to support the bus voltage. Droop control compensates the bus voltage by generating reactive power and maintains voltage balance. The method of controlling the supercapacitor to compensate the bus voltage through droop control will be described in detail below with reference to the accompanying drawings.

FIG. 6 is a block diagram of a phase angle calculation unit according to an exemplary embodiment of the present invention. FIG. 7 is a block diagram of a voltage amplitude calculation unit according to an exemplary embodiment of the present invention.

FIG. 6 shows a block diagram of calculating a phase angle by a phase angle calculation unit. The phase angle calculation unit can calculate the phase angle of the output voltage of the supercapacitor according to the active power, the given active power, and the rated frequency of the microgrid. Referring to FIG. 6 , the given active power value is the active power value corresponding to state A in FIG. 5 . The frequency droop coefficient is the slope of the schematic graph of frequency droop control shown in FIG. 5 , that is, Δf/ΔP. Next, the frequency droop coefficient may be calculated according to the active power, the given active power, and the rated frequency of the microgrid. Then, 2π×(50-frequency droop coefficient) outputs the phase angle through the integration link. The phase angle calculation of the droop control does not have a phase-locked loop link, and will not be affected by the frequency signal of the bus when calculating the phase angle, but uses a given frequency (eg 50 Hz) to output a standard phase angle through the integration link.

Fig. 7 shows a block diagram of calculating the voltage amplitude by the voltage amplitude calculation unit. The voltage amplitude calculation unit can calculate the output voltage amplitude of the supercapacitor according to the reactive power, the given reactive power, and the rated voltage of the microgrid. Referring to FIG. 7 , the given reactive power value is the reactive power value corresponding to state A in FIG. 4 . The voltage droop coefficient is the slope of the schematic graph of voltage droop control shown in FIG. 4 , that is, ΔV/ΔQ. Next, the voltage droop coefficient can be calculated according to the reactive power, the predetermined reactive power and the rated voltage of the microgrid. The voltage amplitude is mainly determined according to the rated voltage V ₀ , that is, the voltage amplitude of the voltage droop control output fluctuates around the rated voltage.

Therefore, in step S203, the discharge control unit 103 may control the discharge of the supercapacitor according to the calculated phase angle and amplitude of the output voltage of the supercapacitor, so as to adjust the voltage of the microgrid bus.

FIG. 8 is a block diagram of a voltage reference value calculation unit according to an exemplary embodiment of the present invention. The voltage reference calculation unit calculates the cosine values of the output phase angle, the output phase angle + 2/3π, and the output phase angle -2/3π respectively according to the output phase angle, and multiplies them with the output voltage amplitude respectively to obtain The product is subjected to Clark (Clark) coordinate axis transformation and Park (Park) coordinate axis transformation to obtain a d-axis reference voltage and a q-axis reference voltage respectively.

Fig. 9 is a block diagram of a dual-loop control strategy of positive sequence voltage outer loop and current inner loop according to an exemplary embodiment of the present invention. In the control strategy, positive-sequence extraction is performed on the detected real-time voltage to obtain positive-sequence voltage feedback V _pd on the d-axis and positive-sequence voltage feedback V _pq on the q-axis. Positive-sequence two-phase rotating coordinate components based on Space Vector Pulse Width Modulation (SVPWM).

Fig. 10 is a block diagram of a dual-loop control strategy of negative sequence voltage outer loop and current inner loop according to an exemplary embodiment of the present invention. In the control strategy, negative-sequence extraction is performed on the detected real-time voltage to obtain the positive-sequence voltage feedback V _nd of the d-axis and the positive-sequence voltage feedback V _nq of the q-axis. It is based on the negative sequence two-phase rotating coordinate component of Space Vector Pulse Width Modulation (SVPWM).

In other words, referring to FIG. 9 and FIG. 10 , the discharge control unit can calculate the positive sequence component of the space vector pulse width modulation according to the d-axis reference voltage and the d-axis positive sequence voltage and the q-axis reference voltage and the q-axis positive sequence voltage feedback, so that micro The positive sequence component of the voltage of the grid bus is within the rated range. Here, the d-axis positive-sequence voltage feedback and the q-axis positive-sequence voltage feedback are the positive-sequence components obtained by extracting the positive and negative sequences of the real-time voltage. In addition, the discharge control unit can calculate the negative sequence component of the space vector pulse width modulation according to the d-axis negative sequence voltage feedback and the q-axis negative sequence voltage feedback, so as to compensate the voltage of the busbar of the microgrid and eliminate the negative sequence of the voltage of the busbar of the microgrid portion. Here, the d-axis negative-sequence voltage feedback and the q-axis negative-sequence voltage feedback are the negative-sequence components obtained by extracting the positive and negative sequences of the real-time voltage.

The positive-sequence two-phase rotating coordinate component and the negative-sequence two-phase rotating coordinate component used in SVPWM can compensate the voltage unbalance, make the positive sequence component of the system voltage within a predetermined range, and offset the negative sequence component of the system voltage.

Optionally, in order to prevent the supercapacitor from being over-discharged and improve the lifespan of the supercapacitor, the control method of the supercapacitor may also include the following steps: the detection unit 101 detects whether the stored charge of the supercapacitor is less than a predetermined value; when the supercapacitor stores When the amount of charge in the supercapacitor is less than the predetermined value, the control unit controls the supercapacitor to stop discharging; when the charge amount stored in the supercapacitor is greater than the predetermined value, return to the detection unit 101 to perform the step of detecting the real-time voltage and real-time current of the microgrid bus.

As mentioned above, during the operation of the microgrid, the voltage and current of the bus are monitored in real time, and at the same time, the discharge of the supercapacitor is controlled according to the control method described in Fig. 2 to Fig. 10 to compensate the voltage of the bus.

The technical effect of the present invention will be described below with reference to FIG. 11 to FIG. 13 .

FIG. 11 is a block diagram of a microgrid according to an exemplary embodiment of the present invention. A microgrid according to an exemplary embodiment of the present invention may include a supercapacitor 10, a supercapacitor converter 11, a supercapacitor transformer 12, a supercapacitor switch 13, a flow battery 20, a flow battery converter 21, a flow battery Transformer 22 , liquid flow battery switch 23 , important load 30 , photovoltaic power station 40 , photovoltaic power station converter 41 , photovoltaic power station transformer 42 , photovoltaic power station switch 43 , sensitive load 50 , and sensitive load switch 51 .

The microgrid shown in Figure 11 uses a 200KW/4h flow battery, a 200KW/10s supercapacitor, and a 150KW photovoltaic power station. The load is selected as an important load of 75KW and a sensitive load of 12KW.

The supercapacitor in FIG. 11 is controlled by the control method according to the exemplary embodiment of the present invention and the existing control method respectively, and the voltage and current of the bus are respectively collected when the 12KW sensitive load 51 in FIG. 11 starts suddenly.

FIG. 12 and FIG. 13 respectively show the current transient curve and the voltage transient curve during the cut-in process of the sensitive load 51 . In Fig. 12, the solid line curve represents adopting the control method according to the exemplary embodiment of the present invention to control the current transient curve diagram of the supercapacitor, and the dotted line curve represents the current transient curve diagram adopting the existing control method to control the supercapacitor , as can be seen from Fig. 12, adopting the control method according to the exemplary embodiment of the present invention to control the supercapacitor, the bus current can return to normal after two cycles, and the control method adopted to control the supercapacitor needs to go through six cycles The bus current can return to normal. In Fig. 13, the solid line curve represents adopting the control method according to the exemplary embodiment of the present invention to control the voltage transient curve diagram of the supercapacitor, and the dotted line curve represents adopting the existing control method to control the voltage transient curve diagram of the supercapacitor , as can be seen from Fig. 13, adopting the control method according to the exemplary embodiment of the present invention to control the supercapacitor, the bus voltage can return to normal after one cycle of bus voltage, while the control method adopted to control the supercapacitor needs to go through nine cycle bus voltages voltage returns to normal.

It can be seen from Fig. 12 and Fig. 13 that when the load changes suddenly, adopting the control method according to the exemplary embodiment of the present invention to control the supercapacitor can give full play to the advantages of quick start of the supercapacitor compared with the existing control method, and can Make the bus voltage return to normal faster, can better improve the power quality.

In addition, according to the supercapacitor control method in the microgrid of the exemplary embodiment of the present invention to control the supercapacitor, the supercapacitor controller has a plug-and-play function, and only needs to change the supercapacitor according to the voltage and frequency changes on the bus Its own power output to stabilize bus voltage and frequency.

In addition, the supercapacitor is controlled according to the supercapacitor control method in the microgrid according to the exemplary embodiment of the present invention, because the supercapacitor does not communicate with the rest of the distributed power sources, which saves the communication time and does not collect the information of the other main power sources. The power output saves the acquisition and calculation time of nearly one cycle, which can be faster than the current supercapacitor control method.

In addition, controlling the supercapacitor according to the supercapacitor control method in the microgrid according to the exemplary embodiment of the present invention can allow the supercapacitor to enter the linear operation region by setting a reasonable droop coefficient.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

Claims (14)

1. a control method of a supercapacitor in a microgrid, characterized in that, the control method of the supercapacitor comprises: The detection unit detects the real-time voltage and real-time current of the microgrid bus; a real-time power calculation unit calculates active power and reactive power based on the real-time voltage and the real-time current; The discharge control unit controls the discharge of the supercapacitor according to the active power and the reactive power, so as to adjust the voltage of the microgrid bus. 2. the control method of supercapacitor according to claim 1, is characterized in that, the step of controlling supercapacitor discharge comprises: The phase angle calculation unit calculates the phase angle of the supercapacitor output voltage according to the active power, the given active power, and the rated frequency of the microgrid; The voltage amplitude calculation unit calculates the amplitude of the output voltage of the supercapacitor according to the reactive power, the given reactive power, and the rated voltage of the microgrid; The discharge control unit controls the discharge of the supercapacitor according to the calculated phase angle and amplitude of the output voltage of the supercapacitor, so as to adjust the voltage of the microgrid bus. 3. The control method of the supercapacitor according to claim 2, wherein the step of calculating the phase angle of the supercapacitor output voltage comprises: the phase angle calculation unit according to the active power, the given active power and the microgrid The rated frequency calculates the frequency droop coefficient, and calculates the phase angle of the supercapacitor output voltage according to the calculated frequency droop coefficient and the rated frequency of the microgrid. 4. the control method of supercapacitor according to claim 2, is characterized in that, the step of calculating the magnitude of supercapacitor output voltage comprises: voltage magnitude calculating unit according to described reactive power, given reactive power and The rated voltage of the microgrid calculates the voltage droop coefficient, and calculates the amplitude of the output voltage of the supercapacitor according to the calculated voltage droop coefficient and the rated voltage of the microgrid. 5. the control method of supercapacitor according to claim 2, is characterized in that, controls supercapacitor discharge according to the phase angle and the magnitude of the supercapacitor output voltage of calculation, to regulate the step of the voltage of microgrid bus bar: The voltage reference calculation unit calculates a d-axis reference voltage and a q-axis reference voltage based on the phase angle and amplitude of the supercapacitor output voltage; The discharge control unit calculates the positive sequence component of the space vector pulse width modulation according to the d-axis reference voltage and the d-axis positive sequence voltage feedback and the q-axis reference voltage and the q-axis positive sequence voltage feedback, so that the voltage of the microgrid bus The positive-sequence component is within the rated range, and the d-axis positive-sequence voltage feedback and the q-axis positive-sequence voltage feedback are positive-sequence components obtained by extracting the positive and negative sequences of the real-time voltage; The discharge control unit calculates the negative sequence component of the space vector pulse width modulation according to the d-axis negative sequence voltage feedback and the q-axis negative sequence voltage feedback, so as to compensate the voltage of the busbar of the microgrid and eliminate the negative sequence component of the voltage of the busbar of the microgrid. The d-axis negative-sequence voltage feedback and the q-axis negative-sequence voltage feedback are negative-sequence components obtained by extracting positive and negative sequences from the real-time voltage. 6. the control method of supercapacitor according to claim 1, is characterized in that, the step of calculating active power and reactive power comprises: real-time power calculation unit carries out Clark's coordinate axis conversion and described real-time voltage and described real-time current Transforming the Parker coordinate axis, and calculating the active power and the reactive power according to the real-time voltage and real-time current after the Clarke coordinate axis transformation and the Parker coordinate axis transformation. 7. the control method of supercapacitor according to claim 1, is characterized in that, the control method of described supercapacitor also comprises: The detection unit detects whether the stored charge of the supercapacitor is less than a predetermined value; When the amount of charge stored in the supercapacitor is less than the predetermined value, the control unit controls the supercapacitor to stop discharging; When the charge stored in the supercapacitor is greater than the predetermined value, return to the detection unit to perform the step of detecting the real-time voltage and real-time current of the bus bar of the microgrid. 8. A control device for a supercapacitor in a microgrid, characterized in that the control device for the supercapacitor comprises: The detection unit detects the real-time voltage and real-time current of the microgrid bus; a real-time power calculation unit, calculating active power and reactive power based on the real-time voltage and the real-time current; The discharge control unit controls the discharge of the supercapacitor according to the active power and the reactive power, so as to adjust the voltage of the busbar of the microgrid. 9. The control device of supercapacitor according to claim 8, wherein the discharge control unit comprises: The phase angle calculation unit calculates the phase angle of the supercapacitor output voltage according to the active power, the given active power, and the rated frequency of the microgrid; The voltage amplitude calculation unit calculates the amplitude of the output voltage of the supercapacitor according to the reactive power, the given reactive power, and the rated voltage of the microgrid; Wherein, the discharge control unit controls the discharge of the supercapacitor according to the calculated phase angle and amplitude of the output voltage of the supercapacitor, so as to adjust the voltage of the microgrid bus. 10. The control device of the supercapacitor according to claim 9, wherein the phase angle calculation unit calculates the frequency droop coefficient according to the rated frequency of the active power, the given active power and the microgrid, and according to the calculated frequency The phase angle of the supercapacitor output voltage is calculated from the droop coefficient and the rated frequency of the microgrid. 11. The control device of the supercapacitor according to claim 9, wherein the voltage amplitude calculation unit calculates the voltage droop coefficient according to the reactive power, the given reactive power and the rated voltage of the microgrid, and according to The calculated voltage droop coefficient and the rated voltage of the microgrid are used to calculate the magnitude of the output voltage of the supercapacitor. 12. The control device of supercapacitor according to claim 9, wherein the discharge control unit further comprises: A voltage reference calculation unit, which calculates a d-axis reference voltage and a q-axis reference voltage based on the phase angle and amplitude of the supercapacitor output voltage; Wherein, the discharge control unit calculates the positive sequence component of space vector pulse width modulation according to the d-axis reference voltage and d-axis positive sequence voltage feedback and the q-axis reference voltage and q-axis positive sequence voltage feedback, so that the microgrid bus The positive-sequence component of the voltage is within the rated range, and the d-axis positive-sequence voltage feedback and the q-axis positive-sequence voltage feedback are positive-sequence components obtained by extracting the positive and negative sequences of the real-time voltage; The discharge control unit calculates the negative sequence component of the space vector pulse width modulation according to the d-axis negative sequence voltage feedback and the q-axis negative sequence voltage feedback, so as to compensate the voltage of the busbar of the microgrid and eliminate the negative sequence component of the voltage of the busbar of the microgrid. The d-axis negative-sequence voltage feedback and the q-axis negative-sequence voltage feedback are negative-sequence components obtained by extracting positive and negative sequences from the real-time voltage. 13. The control device of the supercapacitor according to claim 8, wherein the real-time power calculation unit performs Clarke coordinate axis conversion and Parker coordinate axis conversion on the real-time voltage and the real-time current, and transforms the real-time power according to the Clarke coordinate axis The active power and the reactive power are calculated from the real-time voltage and real-time current transformed with the Parker coordinate axis. 14. The control device of the supercapacitor according to claim 8, wherein the detection unit also detects whether the stored charge of the supercapacitor is less than a predetermined value; when the stored charge of the supercapacitor is less than the predetermined value, the control The unit controls the supercapacitor to stop discharging; when the charge stored in the supercapacitor is greater than the predetermined value, the detection unit continues to detect the real-time voltage and real-time current of the microgrid bus.