A control method for bidirectional ac-dc power supply and a light storage charging and inspection system

Abstract

The application discloses a control method for AC / DC bidirectional power supply and a light storage charging and detecting system. According to the AC load demand power and the capacity of the isolation transformer shared by the light storage charging microgrid system and the AC load, the range of the available charging power of the commercial power through the PCS is determined. According to the battery SOC, the peak-valley information of the electricity price and the preset SOC threshold, the energy scheduling strategy for the DC load, the AC load, the photovoltaic mechanism and the energy storage mechanism is determined, and the specific energy value calculation and scheduling are carried out in combination with the range of the available charging power of the commercial power through the PCS. Considering the capacity of the isolation transformer shared by the AC load, the power supply provided by the commercial power is determined again, and the energy scheduling strategy for the DC load, the AC load, the photovoltaic mechanism and the energy storage mechanism is determined in combination with the battery SOC, the peak-valley information of the electricity price and the preset SOC threshold, so that the maximization of the energy benefit and the economic benefit of the AC / DC bidirectional power supply is ensured.

Description

Technical Field

[0001] The present invention relates to the field of power grid control technology, and in particular to a control method for AC / DC bidirectional power supply and a photovoltaic storage charging and testing system. Background Art

[0002] In recent years, as the energy crisis intensifies, microgrids have become a research hotspot in the energy sector both domestically and internationally. Microgrid systems combine distributed power sources, loads, energy storage devices, and control systems to form a small power system. These systems offer advantages such as flexibility, controllability, low carbon footprint, environmental friendliness, and improved stability and reliability.

[0003] Existing PV-storage-charging-inspection microgrid systems primarily supply DC loads, combining photovoltaics and energy storage batteries to rapidly charge electric vehicles without discharging to the AC grid. In response to customer demand, PV-storage-charging-inspection microgrid systems need to reduce electricity costs, achieve flexible and economically optimized operation between PV, storage, and charging resources to meet diverse objectives, and ultimately maximize energy and economic benefits.

[0004] Based on this, it is necessary to develop a control method for AC / DC bidirectional power supply and a photovoltaic storage charging and detection system. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a control method for AC / DC bidirectional power supply and a photovoltaic storage charging and testing system, which can support and reasonably control the power supply to DC loads and AC loads.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for controlling AC / DC bidirectional power supply, comprising the steps of:

[0008] S1, according to the AC load power P 交 The capacity S of the upper isolation transformer shared by the solar-storage-charging microgrid system and the AC load determines the range of available charging power from the mains through the PCS:

[0009] When (SP 交 )>P 充max When P PCS ≤P 充max ;

[0010] When (SP 交 )≤P 充max When P PCS ≤(SP 交 );

[0011] Among them, (SP 交 ) represents the charging power that can be supplied to the photovoltaic storage and charging microgrid system, P充max Indicates the maximum charging power rated by PCS, P PCS Indicates the available charging power of the mains through the PCS;

[0012] S2. Determine the energy dispatch strategy for DC loads, AC loads, photovoltaic devices, and energy storage devices based on the battery SOC, peak and valley information of electricity prices, and the preset SOC threshold. Calculate and dispatch specific energy values ​​based on the range of available charging power of the mains through the PCS.

[0013] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0014] An AC / DC bidirectional power supply photovoltaic storage charging and testing system includes a DC bus, a photovoltaic mechanism, an energy storage mechanism, a PCS, an isolation transformer, and an AC load;

[0015] The photovoltaic mechanism and the energy storage mechanism are connected to the DC bus;

[0016] The DC bus is connected to the isolation transformer and the AC load through the PCS;

[0017] The isolation transformer is connected to the mains;

[0018] The DC bus, the photovoltaic mechanism, the energy storage mechanism, the PCS, the isolation transformer, and the AC load are controlled to implement the steps in the above-mentioned method for controlling AC / DC bidirectional power supply.

[0019] The beneficial effects of the present invention are as follows: a control method for AC / DC bidirectional power supply and a photovoltaic storage charging and testing system of the present invention considers the capacity of the upper isolation transformer shared by the AC load, redetermines the power supply that can be provided by the mains, and combines the battery SOC, peak and valley information of electricity prices and a preset SOC threshold to determine the energy scheduling strategy for the DC load, AC load, photovoltaic mechanism and energy storage mechanism, thereby ensuring the maximization of the energy efficiency and economic benefits of the AC / DC bidirectional power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart of a control method for AC / DC bidirectional power supply according to an embodiment of the present invention;

[0021] Figure 2 This is a structural diagram of a control device for AC / DC bidirectional power supply according to an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the architecture of a photovoltaic storage charging and testing system for AC / DC bidirectional power supply according to an embodiment of the present invention;

[0023] Description of labels:

[0024] 1. A control device for bidirectional AC / DC power supply; 2. a processor; 3. a memory. DETAILED DESCRIPTION

[0025] To illustrate the technical content of the present application, the purposes and effects achieved are described in detail below in combination with the embodiments and the accompanying drawings.

[0026] Please refer to Figure 1 A control method for bidirectional AC / DC power supply, comprising the steps of:

[0027] S1, determining the range of available charging power of the mains through the PCS according to the AC load demand power P 交 and the capacity S of the isolation transformer of the upper level shared by the PV-charging microgrid system and the AC load;

[0028] When (S-P 交 )>P 充max , P PCS ≤P 充max ;

[0029] When (S-P 交 )≤P 充max , P PCS ≤(S-P 交 );

[0030] Wherein, (S-P 交 ) represents the charging power available for the PV-charging microgrid system, P 充max represents the maximum charging power of the PCS, and P PCS represents the available charging power of the mains through the PCS.

[0031] S2, determining the energy scheduling strategy for the DC load, the AC load, the PV mechanism and the energy storage mechanism according to the battery SOC, the peak-valley information of the electricity price and the preset SOC threshold, and combining the range of available charging power of the mains through the PCS to calculate and schedule the specific energy values.

[0032] From the above description, the beneficial effects of the present application are as follows: the control method for bidirectional AC / DC power supply of the present application considers the capacity of the isolation transformer of the upper level shared by the AC load, re-determines the power supply that can be provided by the mains, and combines the battery SOC, the peak-valley information of the electricity price and the preset SOC threshold to determine the energy scheduling strategy for the DC load, the AC load, the PV mechanism and the energy storage mechanism, so as to maximize the energy efficiency and economic benefit of bidirectional AC / DC power supply.

[0033] Further, step S2 comprises the steps of:

[0034] S21, if the battery SOC is less than the SOC threshold value, the AC load is not discharged, and the DC load demand power, photovoltaic power and the available charging power of the grid through the PCS are compared, and the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the grid and the DC load is determined according to the comparison result.

[0035] From the above description, it can be seen that when the electricity price is valley electricity, if the battery SOC is small, the power supply to the AC load does not need to be considered, and the photovoltaic power of the photovoltaic mechanism is preferentially guaranteed for internal power supply, that is, only the DC load and the energy storage mechanism need to be powered.

[0036] Further, the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the grid and the DC load according to the comparison result is specifically:

[0037] If the DC load demand power is less than or equal to the photovoltaic power, the photovoltaic mechanism outputs full power, preferentially supplies power to the DC load, and the remaining power charges the energy storage mechanism:

[0038] P 直 +P 电池 =P PV +P PCS ;

[0039] Wherein, P 直 represents the DC load demand power, P 电池 represents the energy storage mechanism power, and P PV represents the photovoltaic output power.

[0040] If the DC load demand power is greater than the photovoltaic power, and the DC load demand power is less than or equal to the sum of the photovoltaic power and the available charging power of the grid through the PCS, the photovoltaic full power is supplied to the DC load, and the remaining DC load demand power is supplemented by the grid, and the remaining available power of the grid is used to charge the energy storage mechanism:

[0041] P 直 +P 电池 =P PV +P PCS ;

[0042] If the DC load demand power is greater than the sum of the photovoltaic power and the available charging power of the grid through the PCS, the photovoltaic mechanism is the first priority, the grid is the second priority, and the energy storage mechanism is the third priority to supply power to the DC load.

[0043] From the above description, in the valley period, if the battery SOC of the energy storage mechanism is low, the power supply of the alternating load does not need to be considered, the photovoltaic mechanism supplies power to the direct current load and the energy storage system, and the insufficient part is supplemented by the commercial power, so as to fully utilize the valley period to supplement the battery SOC of the energy storage mechanism.

[0044] Further, the step S2 comprises the steps of:

[0045] S22, if the valley information of the electricity price is valley electricity, and the battery SOC is greater than or equal to the SOC threshold value, comparing the direct current load demand power, the photovoltaic power generation power, the alternating load demand power and the available charging power of the commercial power through the PCS, and determining the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the commercial power, the alternating load and the direct current load according to the comparison result.

[0046] Further, the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the commercial power, the alternating load and the direct current load according to the comparison result is specifically:

[0047] If the direct current load demand power is greater than the photovoltaic power generation power and less than or equal to the sum of the photovoltaic power generation power and the available charging power of the commercial power through the PCS, the photovoltaic full power is supplied to the direct current load, and the remaining direct current load demand is supplemented by the commercial power:

[0048] P 直 =P PV +P PCS ;

[0049] Wherein, P 直 represents the direct current load demand power, and P PV represents the photovoltaic output power.

[0050] If the direct current load demand power is greater than the sum of the photovoltaic power generation power and the available charging power of the commercial power through the PCS, the photovoltaic mechanism is the first priority, the commercial power is the second priority, and the energy storage mechanism is the third priority to supply power to the direct current load:

[0051] P 直 =P PV +P PCS +P 电池 ;

[0052] Wherein, P 电池 represents the energy storage mechanism power.

[0053] If the direct current load demand power is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism supplies power to the direct current load, and if the battery SOC is greater than the preset first level protection value, the power supply to the alternating load is triggered:

[0054] determining whether the sum of the AC load demand power and the DC load demand power is less than the photovoltaic power, if yes, supplying power to the DC load and the AC load by the photovoltaic mechanism, otherwise, the photovoltaic power of the photovoltaic mechanism is used to meet the DC load demand power first, and then the AC load is supplied with power.

[0055] As can be seen from the above description, during valley electricity, if the photovoltaic power is still surplus after supplying the DC load, the surplus power can be supplied to the AC load to reduce the demand of the AC load for commercial power when the battery SOC is high and the battery does not need to be charged.

[0056] Further, the step S2 comprises the steps of:

[0057] S23, if the peak-valley information of the electricity price is peak electricity, and the battery SOC is greater than or equal to the SOC threshold value, comparing the DC load demand power, the photovoltaic power, the AC load demand power and the maximum discharge power of the energy storage mechanism, and determining the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the AC load, the commercial power and the DC load according to the comparison result.

[0058] Further, the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the AC load, the commercial power and the DC load according to the comparison result is specifically:

[0059] If the DC load demand power is less than or equal to the photovoltaic power, the photovoltaic mechanism supplies power to the DC load, if there is also AC load demand power, determining whether the sum of the DC load demand power and the AC load demand power is less than the photovoltaic power, if yes, the photovoltaic mechanism supplies power to the DC load and the AC load at the same time, if not, the photovoltaic mechanism and the energy storage mechanism supply power to the DC load and the AC load at the same time;

[0060] If the DC load demand power is greater than the photovoltaic power and less than the sum of the photovoltaic power and the maximum discharge power of the battery, the photovoltaic mechanism supplies power to the DC load first, and the energy storage mechanism supplies power, if there is also AC load demand power, the energy storage mechanism supplies power to the AC load at the same time;

[0061] If the DC load demand power is equal to the sum of the photovoltaic power and the maximum discharge power of the battery, the photovoltaic mechanism and the energy storage mechanism supply power to the DC load, and the AC load is not supplied with power;

[0062] If the DC load demand power is greater than the sum of the photovoltaic power and the maximum discharging power of the battery, the photovoltaic mechanism and the energy storage mechanism supply power to the DC load, and the remaining DC load demand power is supplied by the mains power supply, and the AC load is not supplied with power.

[0063] As can be seen from the above description, during the peak electricity period, if the battery power is high, the photovoltaic mechanism is given priority, and the energy storage mechanism is given priority. In the case that there is still power surplus after supplying the DC load, the AC load is further supplied with power to reduce the use of the mains power supply.

[0064] Further, step S2 comprises the steps of:

[0065] S24, if the peak-valley information of the electricity price is peak electricity, and the SOC of the battery is less than the SOC threshold, the energy scheduling strategy between the photovoltaic mechanism, the PCS, the AC load and the DC load is determined according to the DC load demand power and the photovoltaic power.

[0066] Further, the determination of the energy scheduling strategy between the photovoltaic mechanism, the PCS, the AC load and the DC load according to the DC load demand power and the photovoltaic power is specifically:

[0067] If the DC load demand power is equal to the photovoltaic power, the photovoltaic mechanism supplies power to the DC load at full power.

[0068] If the DC load demand power is less than the photovoltaic power, the photovoltaic mechanism supplies power to the DC load first, and the remaining power is used to charge the energy storage mechanism. If the photovoltaic power is greater than the sum of the DC load demand power and the maximum charging power of the energy storage mechanism, the excess part is used to supply power to the AC load.

[0069] As can be seen from the above description, when the electricity price is peak electricity, if the battery SOC is low at the same time, the photovoltaic mechanism supplies power to the DC load, the energy storage mechanism is charged if there is a surplus, and the AC load is supplied with power only when there is still a surplus.

[0070] Please refer to Figure 2 A control device for AC / DC bidirectional power supply, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned control method for AC / DC bidirectional power supply when executing the computer program.

[0071] From the above description, the beneficial effects of the present application are that: the AC / DC bidirectional power supply device of the present application considers the capacity of the isolation transformer of the upper level shared by the AC load, re-determines the power supply that can be provided by the commercial power supply, and combines the SOC of the battery, the peak-valley information of the electricity price and the preset SOC threshold value to determine the energy scheduling strategy for the DC load, the AC load, the photovoltaic mechanism and the energy storage mechanism, so as to maximize the energy efficiency and economic benefit of the AC / DC bidirectional power supply.

[0072] Please refer to Figure 3 , an AC / DC bidirectional power supply photovoltaic storage charging and detection system, comprising a DC bus, a photovoltaic mechanism, an energy storage mechanism, a PCS, an isolation transformer and an AC load;

[0073] The photovoltaic mechanism and the energy storage mechanism are connected with the DC bus;

[0074] The DC bus is connected with the isolation transformer and the AC load through the PCS;

[0075] The isolation transformer is connected with the commercial power supply;

[0076] The DC bus, the photovoltaic mechanism, the energy storage mechanism, the PCS, the isolation transformer and the AC load are controlled to realize the steps in the above-mentioned AC / DC bidirectional power supply control method.

[0077] From the above description, the beneficial effects of the present application are that: the AC / DC bidirectional power supply photovoltaic storage charging and detection system of the present application considers the capacity of the isolation transformer of the upper level shared by the AC load, re-determines the power supply that can be provided by the commercial power supply, and combines the SOC of the battery, the peak-valley information of the electricity price and the preset SOC threshold value to determine the energy scheduling strategy for the DC load, the AC load, the photovoltaic mechanism and the energy storage mechanism, so as to maximize the energy efficiency and economic benefit of the AC / DC bidirectional power supply.

[0078] The AC / DC bidirectional power supply control method and photovoltaic storage charging and detection system of the present application are suitable for the bidirectional power supply control of the photovoltaic storage charging and detection system connected with the AC load.

[0079] Please refer to Figure 1 , the embodiment one of the present application is:

[0080] An AC / DC bidirectional power supply control method, comprising the steps of:

[0081] S1, determining the range of the available charging power of the commercial power supply through the PCS according to the AC load demand power P 交 and the capacity S of the isolation transformer of the upper level shared by the photovoltaic storage micro-grid system and the AC load:

[0082] When (S-P 交 )>P充max P PCS ≤P 充max ;

[0083] When (S-P 交 )≤P 充max , P PCS ≤(S-P 交 );

[0084] Wherein, (S-P 交 ) represents the available charging power of the light storage charging micro-grid system, P 充max represents the maximum rated charging power of the PCS, and P PCS represents the available charging power of the commercial power through the PCS.

[0085] For example, the maximum capacity of the user-side isolation transformer is 200KW, if the AC load demand is 60KW, and the maximum charging power of the PCS is 100KW. At this time, the available power (S-P) that can be drawn from the commercial power by the light storage charging system is (200-60) = 140KW.

[0086] Because the maximum charging power of the PCS is 100KW, which is less than 140KW, the maximum charging power of the light storage charging system can be at most 100KW.

[0087] If the AC load demand is 120KW, and the maximum charging power of the PCS is 100KW. At this time, the available power (S-P) that can be drawn from the commercial power by the light storage charging system is (200-120) = 80KW, which is less than the maximum charging power 100KW of the PCS, so the maximum charging power of the light storage charging system is 80KW. Exceeding 80KW will overload.

[0088] When the light storage charging system draws power from the commercial power, that is, the PCS is in charging, the EMS determines the available charging power according to the two judgments, and performs power scheduling on the PCS within the available charging range, so as to ensure that the system input power + user load power does not exceed the transformer capacity, so as to prevent the transformer switch from overloading and tripping.

[0089] S2, according to the battery SOC, the peak-valley information of the electricity price, and the preset SOC threshold, determine the energy scheduling strategy of the DC load, the AC load, the photovoltaic mechanism and the energy storage mechanism, and combine the range of the available charging power of the commercial power through the PCS to calculate and schedule the specific energy value.

[0090] Step S2 includes the following steps:

[0091] S21, if the peak-valley information of the electricity price is valley electricity, and the battery SOC is less than the SOC threshold, the AC load is not discharged, and further, the photovoltaic power generation power, the available charging power of the mains through the PCS and the DC load demand power are compared, and the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the mains and the DC load is determined according to the comparison result;

[0092] According to the comparison result, the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the mains and the DC load is determined.

[0093] If the DC load demand power is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism outputs full power, preferentially supplies power to the DC load, and charges the energy storage mechanism with the remaining power:

[0094] P 直 +P 电池 =P PV +P PCS ;

[0095] Wherein, P 直 represents the DC load demand power, P 电池 represents the energy storage mechanism power, and P PV represents the photovoltaic output power.

[0096] If the DC load demand power is greater than the photovoltaic power generation power, and the DC load demand power is less than or equal to the sum of the photovoltaic power generation power and the available charging power of the mains through the PCS, the DC load is supplied by the photovoltaic full power, and the remaining DC load demand power is supplemented by the mains, and the remaining available power of the mains is used to supplement the energy storage mechanism:

[0097] P 直 +P 电池 =P PV +P PCS ;

[0098] If the DC load demand power is greater than the sum of the photovoltaic power generation power and the available charging power of the mains through the PCS, the photovoltaic mechanism is the first priority, the mains is the second priority, and the energy storage mechanism is the third priority to supply power to the DC load.

[0099] In this embodiment, the battery target SOC 目标 , i.e. the SOC threshold, is set. When valley electricity, when the actual SOC of the battery is less than the SOC 目标 , the AC side load is not discharged. If the DC load demand power is less than the photovoltaic power generation power, i.e. P 直 <P PV, the photovoltaic mechanism full power output, priority to the DC load power supply, the remaining to the battery charging, the mains through the PCS to the battery charging. If the DC load demand power is greater than the photovoltaic power, less than the photovoltaic plus the power allowed by the mains, the photovoltaic full power output to the DC load, at this time from the mains through the PCS to the DC load power supply, also part of the battery charging. If the DC load demand power is greater than the photovoltaic power + the power allowed by the mains, the photovoltaic full power output to the DC load, at the same time from the mains through the PCS, the power is not enough to be supplemented by the battery output.

[0100] S22, if the battery SOC is greater than or equal to the SOC threshold value, the DC load demand power, the photovoltaic power, the AC load demand power and the available charging power of the mains through the PCS are compared, and the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the mains, the AC load and the DC load is determined according to the comparison result;

[0101] According to the comparison result, the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the mains, the AC load and the DC load is determined.

[0102] If the DC load demand power is greater than the photovoltaic power, and less than or equal to the sum of the photovoltaic power and the available charging power of the mains through the PCS, the photovoltaic full power is supplied to the DC load, and the remaining DC load demand is supplemented by the mains:

[0103] P 直 = P PV + P PCS ;

[0104] Wherein, P 直 represents the DC load demand power, P PV represents the photovoltaic output power;

[0105] If the DC load demand power is greater than the sum of the photovoltaic power and the available charging power of the mains through the PCS, the photovoltaic mechanism is the first priority, the mains is the second priority, and the energy storage mechanism is the third priority to supply power to the DC load:

[0106] P 直 = P PV + P PCS + P 电池 ;

[0107] Wherein, P 电池 represents the energy storage mechanism power;

[0108] If the DC load demand power is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism supplies power to the DC load, and if the battery SOC is greater than a preset first-level protection value of charging, the supply of power to the AC load is triggered:

[0109] If the sum of the AC load demand power and the DC load demand power is less than the photovoltaic power generation power, the photovoltaic mechanism supplies power to the DC load and the AC load, otherwise, the photovoltaic power generation power of the photovoltaic mechanism is used to first meet the DC load demand power, and then the AC load is supplied with power.

[0110] In this embodiment, during valley electricity: when the actual SOC of the battery is greater than or equal to SOC 目标 , the charging and discharging logic is as follows: if the DC load demand power is greater than the photovoltaic power generation power and less than the power allowed by the photovoltaic plus the power grid, the photovoltaic full power is output to the DC load, and the insufficient power is drawn from the power grid through the PCS, at this time, P 直 =P PV +P PCS . If the DC load demand power is greater than the power allowed by the photovoltaic plus the power grid, the photovoltaic full power is output to the DC load, and the insufficient power is drawn from the power grid through the PCS, and the power is supplemented by the battery:

[0111] P 直 =P PV +P PCS +P 电池 .

[0112] If the DC load demand power is less than the photovoltaic power generation power, that is, P 直 <P PV , the photovoltaic power generation power follows the DC load power. At this time, if the AC load has a power demand and the current SOC of the battery reaches the first-level protection value of charging, the discharge to the AC side is triggered. If the DC load + AC load demand power is less than the photovoltaic power generation power, that is, P 直 +P 交 <P PV , the photovoltaic power generation power is limited power output; if the DC load + AC load demand power is greater than or equal to the photovoltaic power generation power P 直 +P 交需 ≥P PV , the photovoltaic full power is discharged, P 交 =P PV -P 直 .

[0113] S23, if the peak-valley information of the electricity price is a peak electricity time, and the battery SOC is greater than or equal to the SOC threshold value, then the direct-current load demand power, the photovoltaic power generation power, the alternating-current load demand power and the maximum discharge power of the energy storage mechanism are compared, and an energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the alternating-current load, the commercial power and the direct-current load is determined according to the comparison result;

[0114] According to the comparison result, the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the alternating-current load, the commercial power and the direct-current load is determined.

[0115] If the direct-current load demand power is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism supplies power to the direct-current load, and if there is an alternating-current load demand power at the same time, it is judged whether the sum of the direct-current load demand power and the alternating-current load demand power is less than the photovoltaic power generation power, if yes, the photovoltaic mechanism supplies power to the direct-current load and the alternating-current load at the same time, and if no, the photovoltaic mechanism and the energy storage mechanism supply power to the direct-current load and the alternating-current load at the same time.

[0116] If the direct-current load demand power is greater than the photovoltaic power generation power and less than the sum of the photovoltaic power generation power and the maximum discharge power of the battery, the photovoltaic mechanism supplies power to the direct-current load preferentially, and the energy storage mechanism supplies power complementarily, and if there is an alternating-current load demand power at the same time, the energy storage mechanism supplies power to the alternating-current load at the same time.

[0117] If the direct-current load demand power is equal to the sum of the photovoltaic power generation power and the maximum discharge power of the battery, the photovoltaic mechanism and the energy storage mechanism supply power to the direct-current load, and no power is supplied to the alternating-current load.

[0118] If the direct-current load demand power is greater than the sum of the photovoltaic power generation power and the maximum discharge power of the battery, the photovoltaic mechanism and the energy storage mechanism supply power to the direct-current load, and the remaining direct-current load demand power is supplied by the commercial power, and no power is supplied to the alternating-current load.

[0119] In the embodiment, the maximum discharge power P 放max of the PCS is set. BDmax The maximum discharge power P 目标 of the battery is set. When the actual SOC of the battery is greater than SOC 直 , the direct-current load demand power is less than the photovoltaic power generation power, that is, P PV + P 直 is less than the photovoltaic power generation power, that is, P 交 + P PV, the photovoltaic power limited power output. If the DC load + AC load demand power is greater than or equal to the photovoltaic power P 直 +P 交 ≥P PV , the photovoltaic and battery simultaneously discharge to the AC side P PCS =P PV -P 直 +P 电池 , if P 交 >P 放max , P PCS =P 放max . If P 交 P 放max , P PCS =P 交 . If the DC load demand power is greater than the photovoltaic power, less than (the maximum battery discharge power + photovoltaic output power), the photovoltaic full power output to the DC load, not enough to discharge by the battery to supplement. At this time if the AC load has demand power, the battery also supplies power to the AC load. P PCS =P PV +P 电池 -P 直 . If P 交 >P 放max , P PCS =P 放max . If P 交 P 放max , P PCS =P 交 . If the DC load demand power is equal to (the maximum battery discharge power + photovoltaic output power), the photovoltaic and battery output to the DC load, no power supply to the AC side load. P 直 =P PV +P 电池 . If the DC load demand power is greater than (the maximum battery discharge power + photovoltaic output power), the photovoltaic and battery full power output to the DC load, while pulling electricity from the grid through the PCS. P 直 =P PV +P BDmax +P PCS .

[0120] S24, if the peak-valley information of the electricity price is peak electricity, and the battery SOC is less than the SOC threshold value, according to the DC load demand power and the photovoltaic power, an energy scheduling strategy between the photovoltaic mechanism, the PCS, the AC load and the DC load is determined.

[0121] According to the DC load demand power and the photovoltaic power, the energy scheduling strategy between the photovoltaic mechanism, the PCS, the AC load and the DC load is determined, specifically:

[0122] If the DC load demand power is equal to the photovoltaic power generation power, the photovoltaic mechanism supplies power to the DC load at full power.

[0123] If the DC load demand power is less than the photovoltaic power generation power, the photovoltaic mechanism supplies power to the DC load preferentially, and the remaining power charges the energy storage mechanism, and if the photovoltaic power generation power is greater than the sum of the DC load demand power and the maximum charging power of the energy storage mechanism, the excess part supplies power to the AC load.

[0124] In the embodiment, when the actual SOC of the battery is less than the SOC 目标 , the charging and discharging logic is as follows:

[0125] If the DC load demand power is equal to the photovoltaic power generation power, i.e. 直 P PV， The photovoltaic full power supplies power to the DC load, if the DC load demand power is less than the photovoltaic power generation power, i.e. 直 P PV， The photovoltaic mechanism supplies power to the DC load preferentially, if P PV P 直 P BCmax , the remaining part charges the battery, P 电池 P PV P 直 , if P PV P 直 P BCmax , the AC load is supplied with power, P 交 P PV P 直 P Bcmax .

[0126] Please refer to Figure 2 , the second embodiment of the present application is:

[0127] A control device 1 for AC / DC bidirectional power supply, comprising a processor 2, a memory 3, and a computer program stored in the memory 3 and executable on the processor 2, wherein the processor 2 implements the steps in the control method for AC / DC bidirectional power supply in the first embodiment.

[0128] Please refer to Figure 3 , the second embodiment of the present application is:

[0129] A photovoltaic energy storage charging and detecting system for AC / DC bidirectional power supply, comprising a DC bus, a photovoltaic mechanism, an energy storage mechanism, a PCS, an isolation transformer, and an AC load.

[0130] The photovoltaic mechanism and the energy storage mechanism are connected to the DC bus.

[0131] The direct current bus connects the isolation transformer and the alternating current load through the PCS;

[0132] The isolation transformer is connected to the commercial power supply;

[0133] The direct current bus, the photovoltaic mechanism, the energy storage mechanism, the PCS, the isolation transformer and the alternating current load are controlled to realize the steps in the control method for bidirectional power supply of alternating current and direct current in the above embodiment one.

[0134] In summary, the control method for bidirectional power supply of alternating current and direct current and the light storage charging and detecting system provided by the application consider the capacity of the isolation transformer shared by the alternating current load, re-determine the power supply provided by the commercial power supply, and determine the energy scheduling strategy for the direct current load, the alternating current load, the photovoltaic mechanism and the energy storage mechanism in combination with the battery SOC, the peak-valley information of the electricity price and the preset SOC threshold value, so as to maximize the energy benefit and economic benefit of the bidirectional power supply of alternating current and direct current.

[0135] The above only describes the embodiments of the application, and does not limit the patent range of the application, and any equivalent transformation or direct or indirect application in the related technical field by using the content of the specification and drawings of the application is also included in the patent protection range of the application.

Claims

1. A control method for AC / DC bidirectional power supply, characterized in that: Including steps: S1. Determine the range of available charging power from the mains through the PCS based on the AC load power demand and the capacity of the upper isolation transformer shared by the solar-storage-charging microgrid system and the AC load: When (SP 交 )>P 充max When P PCS ≤P 充max ; When (SP 交 )≤P 充max When P PCS ≤(SP 交 ); Among them, (SP 交 ) represents the charging power that can be supplied to the photovoltaic storage and charging microgrid system, P 充max Indicates the maximum charging power rated by PCS, P PCS Indicates the available charging power of the mains through the PCS; S2. Determine the energy dispatch strategy for DC loads, AC loads, PV modules, and energy storage modules based on the battery SOC, peak and valley information of electricity prices, and preset SOC thresholds. Calculate and dispatch specific energy values ​​based on the range of available charging power from the mains through the PCS. Step S2 includes the steps of: S21: When the peak-valley information of the electricity price indicates valley electricity, if the battery SOC is less than the SOC threshold, the AC load is not discharged, and the DC load power demand, the photovoltaic power generation power, and the available charging power of the mains through the PCS are further compared. The energy scheduling strategy among the photovoltaic mechanism, the energy storage mechanism, the mains, and the DC load is determined based on the comparison result. The energy scheduling strategy among the photovoltaic mechanism, the energy storage mechanism, the mains power and the DC load is determined according to the comparison result as follows: If the DC load power requirement is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism outputs full power and supplies power to the DC load first, and the remaining power is used to charge the energy storage mechanism: P 直 +P 电池 =P PV +P PCS ; Among them, P 直 Indicates the DC load power requirement, P 电池 Indicates the power of the energy storage mechanism, P PV Indicates photovoltaic output power; If the DC load power requirement is greater than the PV power generation, and the DC load power requirement is less than or equal to the sum of the PV power generation and the available charging power of the mains through the PCS, the full PV power is used to power the DC load, and the mains power is used to supplement the remaining DC load power requirement. At the same time, the remaining available power of the mains is used to supplement the energy storage device: P 直 +P 电池 =P PV +P PCS ; If the power demanded by the DC load is greater than the sum of the photovoltaic power generation power and the available charging power of the mains through the PCS, the photovoltaic mechanism is given the first priority, the mains is given the second priority, and the energy storage mechanism is given the third priority to supply power to the DC load; S22. When the peak-valley information of the electricity price is valley electricity, if the battery SOC is greater than or equal to the SOC threshold, the DC load demand power, the photovoltaic power generation power, the AC load demand power and the available charging power of the mains through the PCS are compared, and the energy scheduling strategy among the photovoltaic mechanism, the energy storage mechanism, the mains, the AC load and the DC load is determined according to the comparison result.

2. The AC / DC bidirectional power supply control method according to claim 1, characterized in that: The energy scheduling strategy among the photovoltaic mechanism, the energy storage mechanism, the mains, the AC load, and the DC load is determined according to the comparison result as follows: If the DC load power requirement is greater than the PV power generation, and less than or equal to the sum of the PV power generation and the available charging power of the mains through the PCS, the full PV power is used to supply power to the DC load, and the mains supplies the remaining DC load demand: P 直 =P PV +P PCS ; Among them, P 直 Indicates the DC load power requirement, P PV Indicates photovoltaic output power; If the DC load power requirement is greater than the sum of the photovoltaic power generation power and the available charging power of the mains through the PCS, the photovoltaic mechanism is given the first priority, the mains is given the second priority, and the energy storage mechanism is given the third priority to supply power to the DC load: P 直 =P PV +P PCS +P 电池 ; Among them, P 电池 Indicates the power of the energy storage mechanism; If the DC load power demand is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism will supply power to the DC load. At the same time, if the battery SOC is greater than the preset level 1 charging protection value, the AC load will be powered: Determine whether the sum of the AC load demand power and the DC load demand power is less than the photovoltaic power generation power. If so, the photovoltaic mechanism supplies power to the DC load and the AC load. Otherwise, the photovoltaic power generation power of the photovoltaic mechanism preferentially meets the DC load demand power and then supplies power to the AC load.

3. The AC / DC bidirectional power supply control method according to claim 1, characterized in that: Step S2 includes the steps of: S23. When the peak-valley information of the electricity price is peak electricity, if the battery SOC is greater than or equal to the SOC threshold, the DC load demand power, the photovoltaic power generation power, the AC load demand power and the maximum discharge power of the energy storage mechanism are compared, and the energy scheduling strategy among the photovoltaic mechanism, the energy storage mechanism, the AC load, the mains and the DC load is determined according to the comparison result.

4. The AC / DC bidirectional power supply control method according to claim 3, characterized in that: The energy scheduling strategy among the photovoltaic mechanism, the energy storage mechanism, the AC load, the mains power, and the DC load is determined according to the comparison result as follows: If the DC load power demand is less than or equal to the photovoltaic power generation, the photovoltaic mechanism supplies power to the DC load. If there is also an AC load power demand, it is determined whether the sum of the DC load power demand and the AC load power demand is less than the photovoltaic power generation. If so, the photovoltaic mechanism supplies power to both the DC load and the AC load. Otherwise, the photovoltaic mechanism and the energy storage mechanism supply power to both the DC load and the AC load together. If the DC load power demand is greater than the photovoltaic power generation and less than the sum of the photovoltaic power generation and the maximum discharge power of the battery, the photovoltaic mechanism will be used to supply power to the DC load first, and the energy storage mechanism will provide additional power. If there is also an AC load power demand, the energy storage mechanism will also supply power to the AC load. If the DC load power requirement is equal to the sum of the photovoltaic power generation power and the maximum discharge power of the battery, the photovoltaic mechanism and the energy storage mechanism will be used to power the DC load, and the AC load will not be powered; If the DC load power requirement is greater than the sum of the photovoltaic power generation power and the maximum discharge power of the battery, the photovoltaic mechanism and the energy storage mechanism will supply power to the DC load, and the remaining DC load power requirement will be supplemented by the mains power, and the AC load will not be supplied.

5. The AC / DC bidirectional power supply control method according to claim 1, characterized in that: Step S2 includes the steps of: S24. When the peak-valley information of the electricity price is peak electricity, if the battery SOC is less than the SOC threshold, determine the energy scheduling strategy among the photovoltaic mechanism, PCS, AC load and DC load according to the DC load demand power and the photovoltaic power generation power.

6. The AC / DC bidirectional power supply control method according to claim 5, characterized in that: Based on the DC load power demand and PV power generation, the energy scheduling strategy among the PV system, PCS, AC load, and DC load is determined as follows: If the DC load power requirement is equal to the photovoltaic power generation power, the photovoltaic mechanism supplies power to the DC load at full power; If the power demanded by the DC load is less than the photovoltaic power generation power, the photovoltaic mechanism will prioritize powering the DC load, and the remaining power will be used to charge the energy storage mechanism. If the photovoltaic power generation power is greater than the sum of the power demanded by the DC load and the maximum charging power of the energy storage mechanism, the excess power will be used to power the AC load.

7. A control device for AC / DC bidirectional power supply, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the AC / DC bidirectional power supply control method according to any one of claims 1 to 6 are implemented.

8. An AC / DC bidirectional power supply optical storage charging and testing system, characterized in that: Including DC bus, photovoltaic mechanism, energy storage mechanism, PCS, isolation transformer and AC load; The photovoltaic mechanism and the energy storage mechanism are connected to the DC bus; The DC bus is connected to the isolation transformer and the AC load through the PCS; The isolation transformer is connected to the mains; The DC bus, the photovoltaic mechanism, the energy storage mechanism, the PCS, the isolation transformer, and the AC load are controlled to implement the steps of the AC / DC bidirectional power supply control method according to any one of claims 1 to 6.

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