Alternating current and direct current bidirectional power supply control method and optical storage charging detection system

Abstract

The invention discloses an AC / DC bidirectional power supply control method and an optical storage charging detection system, and the method comprises the steps: determining the range of the available charging power of commercial power passing through a PCS according to the AC load demand power and the capacity of a superior isolation transformer shared by an optical storage charging micro-grid system and an AC load; according to the battery SOC, the peak and valley information of the electricity price and a preset SOC threshold value, determining an energy scheduling strategy for a direct-current load, an alternating-current load, a photovoltaic mechanism and an energy storage mechanism, and calculating and scheduling specific energy values in combination with the range of available charging power of the mains supply passing through the PCS; in consideration of the capacity of an upper-level isolation transformer shared by the alternating-current load, power supply capable of being provided by the mains supply is determined again, and an energy scheduling strategy for the direct-current load, the alternating-current load, the photovoltaic mechanism and the energy storage mechanism is determined in combination with the battery SOC, the peak and valley information of the electricity price and a preset SOC threshold value; and maximization of energy benefit and economic benefit of AC / DC bidirectional power supply is ensured.

Description

Technical Field

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

[0002] In recent years, with the increasing energy crisis, microgrid has gradually become one of the research hotspots in the energy field at home and abroad. The microgrid system combines distributed power sources, loads, energy storage devices and control systems to form a small power system with the advantages of strong flexibility, good controllability, low carbon and environmental protection, better stability and reliability.

[0003] The existing photovoltaic, storage, charging and inspection microgrid system is still mainly used to supply power to DC loads. It combines photovoltaic and energy storage batteries to achieve fast charging of electric vehicles without discharging to the AC grid. In line with customer demand, the photovoltaic, storage, charging and inspection microgrid system needs to reduce electricity expenditure, achieve flexible allocation and economic optimization operation between photovoltaic, storage and charging resources under different goals, and achieve maximum 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 testing 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 control method for AC / DC bidirectional power supply, comprising the steps of:

[0008] S1, according to the AC load power P 交 As well as the upper isolation transformer capacity S shared by the photovoltaic storage charging microgrid system and the AC load, determine the range of available charging power of 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 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 load, AC load, photovoltaic mechanism and energy storage mechanism according to the battery SOC, peak and valley information of electricity price and preset SOC threshold, and calculate and dispatch the specific energy value in combination with the range of available charging power of the mains through 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 comprises 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 AC / DC bidirectional power supply control method.

[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 the city power can provide, and combines the battery SOC, peak and valley information of the electricity price and the 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 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 an AC / DC bidirectional power supply photovoltaic storage charging and testing system according to an embodiment of the present invention;

[0023] Description of labels:

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

[0025] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

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

[0027] S1, according to the AC load power P 交 As well as the upper isolation transformer capacity S shared by the photovoltaic storage charging microgrid system and the AC load, determine the range of available charging power of the mains through the PCS:

[0028] When (SP 交 )>P 充max When P PCS ≤P 充max ;

[0029] When (SP 交 )≤P 充max When P PCS ≤(SP 交 );

[0030] Among them, (SP 交 ) represents the charging power that can be supplied to the photovoltaic storage 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;

[0031] S2. Determine the energy dispatch strategy for DC load, AC load, photovoltaic mechanism and energy storage mechanism according to the battery SOC, peak and valley information of electricity price and preset SOC threshold, and calculate and dispatch the specific energy value in combination with the range of available charging power of the mains through PCS.

[0032] From the above description, it can be seen that the beneficial effects of the present invention are: a control method for AC / DC bidirectional power supply of the present invention takes into account the capacity of the upper isolation transformer shared by the AC load, redetermines the power supply that the city power can provide, and combines the battery SOC, the peak and valley information of the electricity price and the preset SOC threshold to determine the energy scheduling strategy for the DC load, AC load, photovoltaic mechanism and energy storage mechanism, so as to ensure the maximization of the energy efficiency and economic benefits of the AC / DC bidirectional power supply.

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

[0034] S21. When the peak-valley information of the electricity price is valley electricity, if the battery SOC is less than the SOC threshold, the AC load will not be discharged, and the DC load demand power, photovoltaic power generation power and the available charging power of the city power through the PCS will be further compared, and the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the city power and the DC load will be 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, there is no need to consider the power supply to the AC load. The photovoltaic power generation power of the photovoltaic mechanism will give priority to ensuring the internal power supply, that is, it is only necessary to supply power to the DC load and the energy storage mechanism.

[0036] Furthermore, the energy dispatching strategy among the photovoltaic mechanism, the energy storage mechanism, the mains and the DC load is determined according to the comparison result as follows:

[0037] 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:

[0038] P 直 +P 电池 =P PV +P PCS ;

[0039] 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;

[0040] If the DC load power requirement is greater than the photovoltaic power generation, and the DC load power requirement is less than or equal to the sum of the photovoltaic power generation and the available charging power of the mains through the PCS, the full photovoltaic power will be used to supply power to the DC load, and the mains will supplement the remaining DC load power requirement. At the same time, the remaining available power of the mains will be used to supplement the energy storage mechanism:

[0041] P 直 +P 电池 =P PV +P PCS ;

[0042] 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.

[0043] From the above description, it can be seen that during the off-peak period, if the battery SOC of the energy storage mechanism is low, there is no need to consider the power supply of the AC load. The photovoltaic mechanism supplies power to the DC load and the energy storage system, and the shortfall is supplemented by the AC power, thereby making full use of the off-peak period to supplement the battery SOC of the energy storage mechanism.

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

[0045] 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, photovoltaic power generation power, AC load demand power and the available charging power of the city power through the PCS are compared, and the energy scheduling strategy among the photovoltaic mechanism, the energy storage mechanism, the city power, the AC load and the DC load is determined according to the comparison result.

[0046] Furthermore, 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:

[0047] If the DC load power requirement is greater than the photovoltaic power generation, and less than or equal to the sum of the photovoltaic power generation and the available charging power of the mains through the PCS, the full photovoltaic power is used to supply power to the DC load, and the mains supplies the remaining DC load demand:

[0048] P 直 =P PV +P PCS ;

[0049] Among them, P 直 Indicates the DC load power requirement, P PV Indicates photovoltaic output power;

[0050] 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:

[0051] P 直 =P PV +P PCS +P 电池 ;

[0052] Among them, P 电池 Indicates the power of the energy storage mechanism;

[0053] If the DC load power requirement is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism will supply power to the DC load. If the battery SOC is greater than the preset first-level charging protection value, the AC load will be powered:

[0054] 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 first meets the DC load demand power and then supplies power to the AC load.

[0055] From the above description, it can be seen that during off-peak hours, when the battery SOC is high and no charging is required, if the photovoltaic power generation power is still surplus after supplying the DC load, the surplus power can be supplied to the AC load to reduce the AC load's demand for mains electricity.

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

[0057] S23. When the peak and 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, photovoltaic power generation power, AC load demand power and the maximum discharge power of the energy storage mechanism are compared, and the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the AC load, the mains and the DC load is determined according to the comparison result.

[0058] Furthermore, 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 as follows:

[0059] 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 an AC load power demand at the same time, 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 jointly supply power to both the DC load and the AC load.

[0060] 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 an AC load power demand at the same time, the energy storage mechanism will also supply power to the AC load.

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

[0062] If the power demand of the DC load 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 power demand of the DC load will be supplemented by the mains, and the AC load will not be supplied.

[0063] From the above description, it can be seen that during peak power periods, if the battery power is high, the photovoltaic mechanism can be given priority, followed by the energy storage mechanism. If there is still surplus power after supplying the DC load, the AC load can be further powered to reduce the use of municipal electricity.

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

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

[0066] Furthermore, according to the DC load demand power and the photovoltaic power generation power, the energy scheduling strategy between the photovoltaic mechanism, PCS, AC load and DC load is determined as follows:

[0067] 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;

[0068] If the power demanded by the DC load is less than the photovoltaic power generation power, the photovoltaic mechanism will preferentially supply power to the DC load, and the surplus 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 will be used to supply power to the AC load.

[0069] From the above description, it can be seen that when the electricity price is peak, if the battery SOC is low at the same time, the photovoltaic mechanism will supply power to the DC load. If there is surplus power, the energy storage mechanism will be charged. Only when there is still surplus power will the AC load be supplied.

[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 in the above-mentioned control method for AC / DC bidirectional power supply when executing the computer program.

[0071] From the above description, it can be seen that the beneficial effects of the present invention are: an AC / DC bidirectional power supply device of the present invention takes into account the capacity of the upper isolation transformer shared by the AC load, redetermines the power supply that the city power can provide, and combines the battery SOC, the peak and valley information of the electricity price and the preset SOC threshold to determine the energy scheduling strategy for the DC load, AC load, photovoltaic mechanism and energy storage mechanism, so as to ensure the maximization of the energy efficiency and economic benefits of the AC / DC bidirectional power supply.

[0072] Please refer to Figure 3 , an AC / DC bidirectional power supply photovoltaic storage charging and testing 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 to the DC bus;

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

[0075] The isolation transformer is connected to the mains;

[0076] 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 AC / DC bidirectional power supply control method.

[0077] From the above description, it can be seen that the beneficial effects of the present invention are: a photovoltaic storage charging and testing system with AC / DC bidirectional power supply of the present invention takes into account the capacity of the upper isolation transformer shared by the AC load, redetermines the power supply that the city power can provide, and combines the battery SOC, the peak and valley information of the electricity price and the preset SOC threshold to determine the energy scheduling strategy for the DC load, AC load, photovoltaic mechanism and energy storage mechanism, so as to ensure the maximization of the energy efficiency and economic benefits of the AC / DC bidirectional power supply.

[0078] The present invention discloses a control method for AC / DC bidirectional power supply and a photovoltaic storage charging and testing system, which are suitable for bidirectional power supply control of a photovoltaic storage charging and testing system connected to an AC load.

[0079] Please refer to Figure 1 , Embodiment 1 of the present invention is:

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

[0081] S1, according to the AC load power P 交 As well as the upper isolation transformer capacity S shared by the photovoltaic storage charging microgrid system and the AC load, determine the range of available charging power of the mains through the PCS:

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

[0083] When (SP 交 )≤P 充max When P PCS ≤(SP 交 );

[0084] Among them, (SP 交 ) represents the charging power that can be supplied to the photovoltaic storage microgrid system, P 充max Indicates the maximum charging power rated by PCS, P PCS Indicates the available charging power of the AC 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, the maximum charging power of the PCS is 100KW. At this time, the available power (SP) that can be drawn from the mains by the solar storage charging system = (200-60) = 140KW.

[0086] Because the maximum charging power of PCS is 100KW, which is less than 140KW, the maximum charging power of the solar storage and charging system can only reach 100KW.

[0087] If the AC load demand is 120KW, and the maximum charging power of PCS is 100KW, then the available power (SP) that can be drawn from the mains for the solar storage charging system = (200-120) = 80KW, which is less than the maximum charging power of PCS 100KW. Then the maximum charging power of the solar storage charging system is 80KW. If it exceeds 80, it will be overloaded.

[0088] When the solar-storage-charging system is drawing power from the mains, that is, when the PCS is charging, the EMS determines the power available for charging the PCS based on these two factors. Within the available charging range, the power of the PCS is dispatched to ensure that the system input power + user load power does not exceed the transformer capacity to prevent the transformer switch from overloading and tripping.

[0089] S2. Determine the energy dispatch strategy for DC load, AC load, photovoltaic mechanism and energy storage mechanism according to the battery SOC, peak and valley information of electricity price and preset SOC threshold, and calculate and dispatch the specific energy value in combination with the range of available charging power of the mains through PCS.

[0090] Step S2 comprises the steps of:

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

[0092] The energy dispatching strategy among the photovoltaic mechanism, the energy storage mechanism, the mains and the DC load is determined according to the comparison result as follows:

[0093] 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:

[0094] P 直 +P 电池 =P PV +P PCS ;

[0095] 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;

[0096] If the DC load power requirement is greater than the photovoltaic power generation, and the DC load power requirement is less than or equal to the sum of the photovoltaic power generation and the available charging power of the mains through the PCS, the full photovoltaic power will be used to supply power to the DC load, and the mains will supplement the remaining DC load power requirement. At the same time, the remaining available power of the mains will be used to supplement the energy storage mechanism:

[0097] P 直 +P 电池 =P PV +P PCS ;

[0098] 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.

[0099] In this embodiment, the battery target SOC is set 目标 , that is, the SOC threshold. Valley power: when the actual battery SOC < SOC 目标 When the AC side load is not discharged, if the DC load power demand is less than the photovoltaic power generation power, that is, P 直 <P PV, the photovoltaic mechanism outputs at full power, giving priority to supplying power to the DC load, and the rest is used to charge the battery. The mains draws power through the PCS to charge the battery. If the power demanded by the DC load is greater than the photovoltaic power generation power, but less than the power allowed by the photovoltaic plus the mains, the photovoltaic mechanism outputs full power to the DC load. At this time, part of the power is drawn from the mains through the PCS to supply power to the DC load, and part is used to charge the battery. If the power demanded by the DC load is greater than the photovoltaic power generation power + the mains allowable power, the photovoltaic mechanism outputs full power to the DC load, and at the same time draws power from the mains through the PCS, and the insufficient power is supplemented by the battery output.

[0100] 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 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] 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:

[0102] If the DC load power requirement is greater than the photovoltaic power generation, and less than or equal to the sum of the photovoltaic power generation and the available charging power of the mains through the PCS, the full photovoltaic power is used to supply power to the DC load, and the mains supplies the remaining DC load demand:

[0103] P 直 =P PV +P PCS ;

[0104] Among them, P 直 Indicates the DC load power requirement, P PV Indicates photovoltaic output power;

[0105] 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:

[0106] P 直 =P PV +P PCS +P 电池 ;

[0107] Among them, P 电池 Indicates the power of the energy storage mechanism;

[0108] If the DC load power requirement is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism will supply power to the DC load. If the battery SOC is greater than the preset first-level charging protection value, the AC load will be powered:

[0109] 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 first meets the DC load demand power and then supplies power to the AC load.

[0110] In this embodiment, during valley power: when the actual SOC of the battery ≥ SOC 目标 The charging and discharging logic is as follows: If the power demanded by the DC load is greater than the photovoltaic power generation power, but less than the power allowed by the photovoltaic plus the mains, the photovoltaic full power is output to the DC load. If it is insufficient, the mains is used to draw power through the PCS. At this time, P 直 =P PV +P PCS If the power demanded by the DC load is greater than (PV power generation + AC power allowed), the full power of the PV is output to the DC load, and power is drawn from the AC through the PCS. The insufficient power is supplemented by the battery output:

[0111] P 直 =P PV +P PCS +P 电池 .

[0112] If the DC load power requirement is less than the photovoltaic power generation power, that is, P 直 <P PV , the photovoltaic power generation 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 charging protection value, it triggers discharge to the AC side. The power demanded by the DC load + AC load is less than the photovoltaic power generation power, that is, P 直 +P 交 <P PV , photovoltaic power generation power limit output; DC load + AC load demand power is greater than or equal to photovoltaic power generation power P 直 +P 交需 ≥P PV , photovoltaic full power discharge, P 交 =P PV -P 直 .

[0113] 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 between the photovoltaic mechanism, the energy storage mechanism, the AC load, the mains and the DC load is determined according to the comparison result;

[0114] The energy dispatching 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 as follows:

[0115] 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 an AC load power demand at the same time, 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 jointly supply power to both the DC load and the AC load.

[0116] 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 an AC load power demand at the same time, the energy storage mechanism will also supply power to the AC load.

[0117] If the DC load power requirement is equal to the sum of the photovoltaic power generation and the maximum battery discharge power, the photovoltaic mechanism and the energy storage mechanism will supply power to the DC load, and the AC load will not be supplied;

[0118] If the power demand of the DC load 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 power demand of the DC load will be supplemented by the mains, and the AC load will not be supplied.

[0119] In this embodiment, the maximum discharge power P of the PCS is set 放max , the maximum discharge power of the battery P BDmax . During peak power, when the battery actual SOC>SOC 目标 When the charging and discharging logic is as follows: If the DC load demand power is less than the photovoltaic power generation power, that is, P 直 <P PV At this time, if the AC load has a power demand, and the DC load + AC load power demand is less than the photovoltaic power generation power, that is, P 直 +P 交 <P PV, the photovoltaic power generation power is limited to output. If the DC load + AC load demand power is greater than or equal to the photovoltaic power generation power P 直 +P 交 ≥P PV , photovoltaic and battery discharge to the AC side at the same time 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 power demanded by the DC load is greater than the photovoltaic power generation power, but less than (the maximum discharge power of the battery + the photovoltaic output power), the photovoltaic power will be fully output to the DC load, and if it is insufficient, the battery will discharge to supplement it. At this time, if the AC load has a power demand, the battery will also supply power to the AC load. 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 power requirement is equal to (the battery maximum discharge power + the photovoltaic output power), the photovoltaic and battery outputs power to the DC load, and does not supply power to the AC side load. 直 =P PV +P 电池 If the DC load power requirement is greater than (the battery maximum discharge power + the PV output power), the PV and battery will output full power to the DC load, and at the same time draw power from the mains through the PCS. 直 =P PV +P BDmax +P PCS .

[0120] 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;

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

[0122] 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;

[0123] If the power demanded by the DC load is less than the photovoltaic power generation power, the photovoltaic mechanism will preferentially supply power to the DC load, and the surplus 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 will be used to supply power to the AC load.

[0124] In this embodiment, during peak power, when the actual SOC of the battery is less than SOC 目标 When the charge and discharge logic is as follows:

[0125] If the DC load demand power is equal to the photovoltaic power generation power, that is, P 直 =P PV， The photovoltaic power is fully powered to the DC load. If the DC load power demand is less than the photovoltaic power generation power, that is, P 直 <P PV， Photovoltaic power supply to DC loads is preferred. PV -P 直 <P BCmax , then the remaining charge to the battery, P 电池 =P PV -P 直 , if P PV -P 直 >P BCmax , then the AC load is powered, P 交 =P PV -P 直 -P Bcmax .

[0126] Please refer to Figure 2 , Embodiment 2 of the present invention is:

[0127] A control device 1 for AC / DC bidirectional power supply comprises a processor 2, a memory 3, and a computer program stored in the memory 3 and executable on the processor 2. When the processor 2 executes the computer program, the steps in the control method for AC / DC bidirectional power supply described in the first embodiment are implemented.

[0128] Please refer to Figure 3 , Embodiment 2 of the present invention is:

[0129] An AC / DC bidirectional power supply photovoltaic storage charging and testing system comprises 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 DC bus is connected to the isolation transformer and the AC load through the PCS;

[0132] The isolation transformer is connected to the mains;

[0133] 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 control method of AC / DC bidirectional power supply described in the above embodiment 1.

[0134] In summary, the control method of AC / DC bidirectional power supply and the photovoltaic storage charging and testing system provided by the present invention take into account the capacity of the upper isolation transformer shared by the AC load, redetermine the power supply that the city power can provide, and combine the battery SOC, the peak and valley information of the electricity price and the preset SOC threshold to determine the energy scheduling strategy for the DC load, AC load, photovoltaic mechanism and energy storage mechanism, so as to ensure the maximization of the energy efficiency and economic benefits of the AC / DC bidirectional power supply.

[0135] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A control method for AC / DC bidirectional power supply, characterized in that: Includes steps: S1. According to the AC load demand power and the upper isolation transformer capacity shared by the photovoltaic storage charging microgrid system and the AC load, determine the range of available charging power of the mains through the PCS: 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 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 load, AC load, photovoltaic mechanism and energy storage mechanism according to the battery SOC, peak and valley information of electricity price and preset SOC threshold, and calculate and dispatch the specific energy value in combination with the range of available charging power of the mains through PCS.

2. The control method of AC / DC bidirectional power supply according to claim 1, characterized in that: Step S2 comprises the steps of: S21. When the peak-valley information of the electricity price is valley electricity, if the battery SOC is less than the SOC threshold, the AC load will not be discharged, and the DC load demand power, photovoltaic power generation power and the available charging power of the city power through the PCS will be further compared, and the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the city power and the DC load will be determined according to the comparison result.

3. The control method of AC / DC bidirectional power supply according to claim 2, characterized in that: The energy dispatching strategy among the photovoltaic mechanism, the energy storage mechanism, the mains 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 photovoltaic power generation, and the DC load power requirement is less than or equal to the sum of the photovoltaic power generation and the available charging power of the mains through the PCS, the full photovoltaic power will be used to supply power to the DC load, and the mains will supplement the remaining DC load power requirement. At the same time, the remaining available power of the mains will be used to supplement the energy storage mechanism: 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.

4. The control method of AC / DC bidirectional power supply according to claim 1, characterized in that: Step S2 comprises the steps of: 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, photovoltaic power generation power, AC load demand power and the available charging power of the city power through the PCS are compared, and the energy scheduling strategy among the photovoltaic mechanism, the energy storage mechanism, the city power, the AC load and the DC load is determined according to the comparison result.

5. The control method of AC / DC bidirectional power supply according to claim 4, 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 photovoltaic power generation, and less than or equal to the sum of the photovoltaic power generation and the available charging power of the mains through the PCS, the full photovoltaic 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 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: 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 requirement is less than or equal to the photovoltaic power generation power, the photovoltaic mechanism will supply power to the DC load. If the battery SOC is greater than the preset first-level 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 first meets the DC load demand power and then supplies power to the AC load.

6. The control method of AC / DC bidirectional power supply according to claim 1, characterized in that: Step S2 comprises the steps of: S23. When the peak and 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, photovoltaic power generation power, AC load demand power and the maximum discharge power of the energy storage mechanism are compared, and the energy scheduling strategy between the photovoltaic mechanism, the energy storage mechanism, the AC load, the mains and the DC load is determined according to the comparison result.

7. The control method of AC / DC bidirectional power supply according to claim 6, characterized in that: The energy dispatching 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 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 an AC load power demand at the same time, 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 jointly supply power to both the DC load and the AC load. 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 an AC load power demand at the same time, 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 and the maximum battery discharge power, the photovoltaic mechanism and the energy storage mechanism will supply power to the DC load, and the AC load will not be supplied; If the power demand of the DC load 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 power demand of the DC load will be supplemented by the mains, and the AC load will not be supplied.

8. The control method of AC / DC bidirectional power supply according to claim 1, characterized in that: Step S2 comprises 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, the energy scheduling strategy among the photovoltaic mechanism, PCS, AC load and DC load is determined according to the DC load demand power and the photovoltaic power generation power.

9. The control method of AC / DC bidirectional power supply according to claim 8, characterized in that: According to the DC load demand power and the photovoltaic power generation power, the energy scheduling strategy between the photovoltaic mechanism, PCS, AC load and DC load is determined as follows: 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; If the power demanded by the DC load is less than the photovoltaic power generation power, the photovoltaic mechanism will preferentially supply power to the DC load, and the surplus 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 will be used to supply power to the AC load.

10. 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 in the control method of AC / DC bidirectional power supply described in any one of claims 1 to 8 above.

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