CN-117748565-B - Power scheduling device and method for energy storage grid-connected system

CN117748565BCN 117748565 BCN117748565 BCN 117748565BCN-117748565-B

Abstract

The utility model provides a power dispatching device and method of an energy storage grid-connected system, and relates to the field of power dispatching of power grids. The power dispatching device comprises a slow computing unit and a fast computing unit, wherein the slow computing unit is used for obtaining a bus voltage set value, a power grid side reactive power set value or a power factor set value and a power grid side active power set value through computing according to detection signals, grid connection regulations, preset working modes, readings of the electric meter, maximum allowable battery charging current and maximum allowable battery discharging current, and the fast computing unit is used for obtaining an inversion PWM driving signal according to the bus voltage set value, the power grid side reactive power set value or the power factor set value and the power grid side active power set value through computing. The embodiment of the invention adopts the fast computing unit and the slow computing unit, so that the stability and the precision of the power control of the energy conversion device can be improved, and the response delay can be reduced.

Inventors

YU BIN
XUE DUO

Assignees

麦田能源股份有限公司

Dates

Publication Date: 20260512
Application Date: 20231229

Claims (11)

1. The power scheduling device for the energy storage grid-connected system comprises at least one single-machine energy storage inversion device, a load and an ammeter, wherein the at least one single-machine energy storage inversion device is connected with the load and the ammeter, and the power scheduling device is characterized by comprising: The low-speed calculation unit is used for calculating and obtaining a bus voltage set value, a power grid side reactive power set value or a power factor set value and a power grid side active power set value which are required to be sent by the at least one single energy storage inverter according to detection signals, grid-connected regulations, a preset working mode, readings of the ammeter, a maximum allowable battery charging current and a maximum allowable battery discharging current; the rapid calculation unit is used for calculating and obtaining an inversion PWM driving signal according to the bus voltage set value, the power grid side reactive power set value or the power factor set value and the power grid side active power set value so as to control the operation of the at least one single energy storage inversion device; The low-speed computing unit comprises an MPPT computing unit, a bus voltage set value computing unit, a power grid side reactive power set value computing unit and a low-speed power dispatching computing unit, wherein the detection signals comprise digital PV voltage signals, digital PV current signals, digital PV power signals, digital battery voltage signals and digital power grid side voltage signals; the MPPT calculation unit is used for calculating and obtaining a PV voltage set value according to the digital PV voltage signal, the digital PV current signal and the digital PV power signal; The bus voltage set value calculation unit is used for calculating and obtaining the bus voltage set value according to the digital PV voltage signal, the digital battery voltage signal and the digital power grid side voltage signal; The power grid side reactive power set value calculation unit is used for calculating and obtaining a power grid side reactive power set value or a power factor set value which is required to be sent by the at least one single energy storage inverter according to the power grid-connected regulation and the preset working mode; The slow power scheduling calculation unit is used for calculating and obtaining the power grid side active power set value according to the preset working mode, the reading of the ammeter, the maximum allowable battery charging current and the maximum allowable battery discharging current; the rapid calculation unit comprises a voltage loop unit, a current loop unit and a PWM signal output unit; The voltage loop unit is used for calculating and obtaining a PV current loop set value, a battery current loop set value and an inverter current loop set value according to the PV voltage set value, the bus voltage set value, the power grid side reactive power set value or the power factor set value and the power grid side active power set value; the current loop unit is used for respectively generating a first duty ratio indicating signal, a second duty ratio indicating signal and a third duty ratio indicating signal according to the PV current loop set value, the battery current loop set value and the inversion current loop set value; The PWM signal output unit is used for respectively generating a first PWM driving signal, a second PWM driving signal and the inversion PWM driving signal according to the first duty ratio indicating signal, the second duty ratio indicating signal and the third duty ratio indicating signal.
2. The power dispatching device for energy storage grid-tie system of claim 1, wherein the current loop unit comprises a PV current loop, a battery current loop, and an inverter current loop; the PV current loop is used for generating the first duty ratio indication signal according to the PV current loop set value; The battery current loop is used for generating the second duty ratio indication signal according to the battery current loop set value; The inversion current loop is used for generating the third duty ratio indication signal according to the inversion current loop set value.
3. The power dispatching device for an energy storage grid-connected system according to claim 1, wherein the voltage loop unit comprises a PV voltage loop, a first adding unit, a second adding unit, a bus voltage loop, a fast power dispatching calculation unit, a battery power conversion to current unit, a grid side power conversion to current unit and a comparison unit; The PV voltage loop is used for generating a first PV current target value according to the PV voltage set value; The first adding unit is used for superposing the bus voltage set value and the bus voltage upward floating value to generate a bus voltage target value; the first bus voltage ring is used for generating a second PV current target value according to the bus voltage target value; the comparison unit is used for comparing the first PV current target value and the second PV current target value, and taking the smaller one of the first PV current target value and the second PV current target value as the PV current loop set value; The second bus voltage ring is used for generating a target power value according to the bus voltage set value; the second adding unit is used for superposing the target power value and the PV instantaneous power to generate a total power value to be received; the rapid power scheduling calculation unit is used for calculating and obtaining a battery receiving power value and a power grid side receiving power value according to the total power value to be received, the power grid side active power set value, the maximum allowable battery charging power, the maximum allowable battery discharging power and the power grid side active power limit value; The battery power conversion to current unit is used for generating the battery current loop set value according to the battery receiving power value; the power conversion to current unit at the power grid side is used for generating the set value of the inversion current loop according to the set value of reactive power at the power grid side or the set value of the power factor and the power receiving power value at the power grid side.
4. A power dispatching device for an energy storage grid-tie system according to claim 3, wherein the total power to be taken is the sum of the battery take-up power value and the grid-side take-up power value.
5. The power dispatching device for energy storage grid-connected system according to claim 4, wherein the maximum allowable battery charging power is denoted as Pc, the maximum allowable battery discharging power is denoted as Pd, the total power to be accepted is denoted as Po, the grid-side active power set value is denoted as Pa, the grid-side active power limit is denoted as Pm, the battery accepting power value is denoted as Py, and the grid-side accepting power value is denoted as Px; The fast power scheduling calculation unit judges whether Po is greater than Pa+Pc, if so, judges whether Pa+Pc is greater than or equal to 0, if so, judges whether Po-Pc is less than Pm, if so, py=Pc, px=Po-Pc, if not, py=Pc, px=Pm; The fast power scheduling calculation unit judges whether Po is more than Pa+Pc, if so, judging whether Pa+Pc is more than or equal to 0, if not, judging whether Po-Pc is less than 0, if so, py=Pc, px=Po-Pc, and if not, py=Pc, and Px=0; the fast power scheduling calculation unit judges whether Po is larger than Pa+Pc, if not, judges whether Po is smaller than Pa+Pd, if so, py=Pd, px=Po-Pd, and if not, py=Po-Pa, and Px=Pa.
6. The power dispatching device for energy storage grid-tie system of claim 1, wherein the at least one stand-alone energy storage inverter comprises a stand-alone energy storage inverter, wherein the slow computing unit and the fast computing unit in the power dispatching device are both disposed in a controller of the stand-alone energy storage inverter, wherein the controller is connected to the electric meter, and wherein the slow computing unit is configured to receive readings of the electric meter.
7. The power dispatching device for energy storage grid-connected system according to claim 6, wherein the controller comprises a communication microprocessor and a control microprocessor, the slow computing unit is arranged on the communication microprocessor, the fast computing unit is arranged on the control microprocessor, the ammeter is connected with the communication microprocessor and is used for providing readings of the ammeter, or the slow computing unit and the fast computing unit are both arranged on the control microprocessor, and the ammeter is connected with the control microprocessor and is used for providing readings of the ammeter.
8. The power dispatching device for energy storage grid-tie system of claim 1, wherein the at least one stand-alone energy storage inverter comprises a plurality of stand-alone energy storage inverters, the energy storage grid-tie system comprises an energy management system, the energy management system is connected with the electric meter, a slow computing unit in the power dispatching device is arranged in the energy management system and is used for receiving readings of the electric meter, and a fast computing unit in the power dispatching device is respectively arranged in a plurality of controllers of the stand-alone energy storage inverters.
9. The power scheduling method for the energy storage grid-connected system comprises at least one single-machine energy storage inversion device, a load and an ammeter, wherein the at least one single-machine energy storage inversion device is connected with the load and the ammeter, and the power scheduling method is characterized by comprising the following steps of: Calculating to obtain a bus voltage set value, a power grid side reactive power set value or a power factor set value and a power grid side active power set value which are required to be sent by the at least one single energy storage inverter device according to detection signals, grid connection regulations, preset working modes, readings of the ammeter, maximum allowed charging current of a battery and maximum allowed discharging current of the battery, and a power grid side active power set value, wherein the power grid power set value is a power grid side reactive power set value or a power factor set value Calculating to obtain an inversion PWM driving signal according to the bus voltage set value, the power grid side reactive power set value or the power factor set value and the power grid side active power set value so as to control the operation of the at least one single-machine energy storage inversion device; The method specifically comprises the steps of calculating and obtaining a bus voltage set value, a power grid side reactive power set value or a power factor set value and a power grid side active power set value which are required to be sent by at least one single energy storage inverter device according to detection signals, grid-connected regulations, preset working modes, readings of an ammeter, a maximum allowed charging current of a battery and a maximum allowed discharging current of the battery, wherein the method specifically comprises the following steps: The detection signals comprise a digital PV voltage signal, a digital PV current signal, a digital PV power signal, a digital battery voltage signal and a digital power grid side voltage signal; Calculating to obtain a PV voltage set point according to the digital PV voltage signal, the digital PV current signal and the digital PV power signal; calculating according to the digital PV voltage signal, the digital battery voltage signal and the digital power grid side voltage signal to obtain the bus voltage set value; Calculating and obtaining a reactive power set value or a power factor set value of the power grid side which is required to be sent out by the at least one single energy storage inverter according to the grid-connected regulation and the preset working mode of the power grid, and Calculating to obtain the active power set value at the power grid side according to the preset working mode, the reading of the ammeter, the maximum allowable battery charging current and the maximum allowable battery discharging current; And calculating to obtain an inversion PWM driving signal according to the bus voltage set value, the power grid side reactive power set value or the power factor set value and the power grid side active power set value so as to control the operation of the at least one single-machine energy storage inversion device, wherein the method specifically comprises the following steps of: Calculating to obtain a PV current loop set value, a battery current loop set value and an inverter current loop set value according to the PV voltage set value, the bus voltage set value, the grid side reactive power set value or the power factor set value and the grid side active power set value; Generating a first duty cycle indication signal, a second duty cycle indication signal and a third duty cycle indication signal according to the PV current loop set point, the battery current loop set point and the inverter current loop set point, respectively, and And respectively generating a first PWM driving signal, a second PWM driving signal and the inversion PWM driving signal according to the first duty ratio indicating signal, the second duty ratio indicating signal and the third duty ratio indicating signal.
10. The power dispatching method for energy storage grid-connected system according to claim 9, wherein the PV current loop set point, the battery current loop set point and the inverter current loop set point are obtained according to the PV voltage set point, the bus voltage set point, the grid-side reactive power set point or the power factor set point and the grid-side active power set point by calculation, and specifically comprising: Generating a first PV current target value according to the PV voltage set-point; superposing the bus voltage set value and the bus voltage upward floating value to generate a bus voltage target value; Generating a second PV current target value from the busbar voltage target value; Comparing the first PV current target value and the second PV current target value, and taking the smaller of the first PV current target value and the second PV current target value as the PV current loop set point; Generating a target power value according to the bus voltage set value; superposing the target power value and the PV instantaneous power to generate a total power value to be received; Calculating according to the total power to be received, the power grid side active power set value, the maximum allowable battery charging power, the maximum allowable battery discharging power and the power grid side active power limit value to obtain a battery receiving power value and a power grid side receiving power value; generating the battery current loop set point according to the battery receiving power value; And generating the inverter current loop set value according to the reactive power set value or the power factor set value at the power grid side and the power receiving value at the power grid side.
11. The power scheduling method for an energy storage grid-connected system according to claim 10, wherein the maximum allowable battery charging power is denoted as Pc, the maximum allowable battery discharging power is denoted as Pd, the total power to be taken is denoted as Po, the grid-side active power set value is denoted as Pa, the grid-side active power limit value is denoted as Pm, the battery taking power value is denoted as Py, and the grid-side taking power value is denoted as Px; Judging whether Po is greater than Pa+Pc, if so, judging whether Pa+Pc is greater than or equal to 0, if so, judging whether Po-Pc is less than Pm, if so, py=Pc, px=Po-Pc, and if not, py=Pc, px=Pm; Judging whether Po is greater than Pa+Pc, if so, judging whether Pa+Pc is greater than or equal to 0, if not, judging whether Po-Pc is less than 0, if so, py=Pc, px=Po-Pc, and if not, py=Pc, and Px=0; judging whether Po is larger than Pa+Pc, if not, judging whether Po is smaller than Pa+Pd, if so, py=Pd, px=Po-Pd, and if not, py=Po-Pa, and Px=Pa.

Description

Power scheduling device and method for energy storage grid-connected system Technical Field The invention relates to the field of power dispatching of power grids, in particular to a power dispatching device and method for an energy storage grid-connected system. Background The power dispatching of the energy storage grid-connected system needs to meet a plurality of constraint conditions to enable the active power on the power grid side to reach a value required by a customer, wherein the value is a continuously changing value, the constraint conditions are that photovoltaic power is utilized in a maximized mode and green energy cannot be wasted, the charging current and the discharging current of a battery do not exceed the required value, and the delay time does not exceed the required value. Fig. 1 is a schematic structural diagram of a conventional energy storage grid-connected system. As shown in fig. 1, the energy storage grid-connected system comprises at least one single energy storage inverter device, a load 6 and an electric meter 4, wherein the single energy storage inverter device 1 comprises at least one solar panel assembly (PV) 11, an energy conversion device 12 and at least one battery 13. The energy conversion device 12 is connected to at least one PV11, at least one battery 13, an electricity meter 4. The load 6 is connected to the connection of the energy conversion device 12 to the electricity meter 4, and the electricity meter 4 is connected to the grid 5. The at least one single-machine energy storage inverter device comprises a plurality of single-machine energy storage inverter devices 1, 2 and 3, and the plurality of single-machine energy storage inverter devices 1, 2 and 3 are connected in parallel. According to the mandatory requirements of grid-connected regulations of a local power grid and the pre-designated working modes such as spontaneous use, power generation priority, peak clipping and valley filling, forced charging and the like generated by the economic demands of customers on electricity prices, the active power and the reactive power of the power grid side are continuously adjusted by the energy conversion device 12 so as to meet the constraint conditions while completing power dispatching. The existing power scheduling method can be realized through a calculation module arranged in a controller in the energy conversion device, and the calculation module can be a single slow calculation module or a single fast calculation module. When power scheduling is implemented in the slow calculation module, the PV power output by the solar panel assembly is suddenly changed instantaneously, and the battery current set value and the power grid side active power set value calculated by the slow calculation module cannot maintain stability of the bus voltage (the bus voltage is the voltage at two ends of a direct current bus capacitor connected with the input end of the inverter), and usually surplus or insufficient PV power is temporarily transferred to the power grid side, and when the next calculation period arrives, the battery current set value and the power grid side active power set value are recalculated according to new PV power. The slow calculation module indirectly controls the active power at the power grid side, so that the stability, the precision and the response delay of the power control at the alternating current side of the energy conversion device are all deficient. When power scheduling is realized in the rapid calculation module, the instantaneous mutation of the PV power can be kept up, a new battery current set value and a power grid side active power set value can be rapidly recalculated, the energy buffering effect of the power of the battery and the bus capacitor can be fully utilized, the safety of the battery can be ensured, the power grid side active power set value is not influenced, but some numerical values do not need to be rapidly calculated, calculation resource waste can be caused, and the burden of a controller in the energy conversion device is increased. Therefore, there is a strong need to develop a power scheduling apparatus and method capable of improving the stability and accuracy of ac side power control of an energy conversion apparatus and reducing the response delay. Disclosure of Invention For the above-mentioned problems that the stability, the precision and the response delay of the power control of the alternating current side of the energy conversion device are poor due to the fact that the active power of the power grid side is indirectly controlled through the calculation module to realize power scheduling. The application provides a power scheduling device for an energy storage grid-connected system, which comprises At least one single-machine energy storage inversion device, a load and an ammeter; the power scheduling device for the energy storage grid-connected system is characterized by comprising the following components