A multiphase AC system comprising an energy storage device and a method for controlling its power output equalization.

Abstract

The present invention discloses a multiphase AC system comprising energy storage devices and a power equalization control method thereof, the power equalization control method comprising the steps of: S1: obtaining the remaining capacity of a plurality of energy storage devices; S2: calculating the average value of the remaining capacity of the plurality of energy storage devices; and S3: subtracting the average value calculated in step S2 from the remaining capacity of each of the energy storage devices to obtain a difference value, and if the difference value is greater than 0, increasing the output voltage of the corresponding energy storage device to increase the output power of the energy storage device, and if the difference value is less than 0, decreasing the output voltage of the corresponding energy storage device to reduce the output power of the energy storage device. The multiphase AC system comprising energy storage devices and the power equalization control method thereof proposed in the present invention effectively solves the problem of significantly shortening the overall system's operating time.

Description

[Technical Field]

[0001] The present invention relates to the technical field of energy storage devices, and more particularly to a multiphase AC system comprising an energy storage device and a method for controlling the equalization of its power output. [Background technology]

[0002] Energy storage power supplies are devices that store electrical energy and release it when needed. Due to their advantages such as safety, portability, efficiency, and environmental friendliness, they are widely used in fields such as aerial photography, mapping and exploration, mobile medical services, road trips, picnics and camping, and recreational activities. Furthermore, large-capacity energy storage power supplies can provide emergency and backup power for homes and businesses, meeting the basic electricity demands of daily life and businesses during power outages.

[0003] Conventional technologies include AC two-live-line systems consisting of two independent energy storage power sources, and AC three-phase systems consisting of three independent energy storage power sources. However, due to battery mismatches among the two or three independent energy storage power sources, if any one of the energy storage power sources experiences a complete discharge, the system must be shut down, significantly reducing the overall system range. In particular, if a single energy storage power source has a single load connected, or if the single loads are unevenly distributed among multiple energy storage power sources, the power consumption of each energy storage power source in the system becomes even more uneven. The energy storage power source with the higher single load power will have a shorter battery range and will completely discharge faster than the energy storage power source with the lower single load power.

[0004] The above background information is disclosed to aid in understanding the concept and technical proposal of the present invention and does not necessarily constitute prior art of this patent application. Unless there is clear evidence that the above information was published by the filing date of this patent application, the above background information should not be used to evaluate the novelty and ingenuity of this application. [Overview of the Initiative]

[0005] To solve the above technical problems, the present invention proposes a multiphase AC system consisting of an energy storage device and a method for controlling its power equalization, effectively resolving the problem of a significantly reduced operating time for the entire system.

[0006] To achieve the above objectives, the present invention employs the following technical approach.

[0007] In a first aspect, the present invention discloses a method for controlling the equalization of power consumption in a multiphase AC system comprising energy storage devices, the method comprising: S1: obtaining the remaining capacity of a plurality of energy storage devices; S2: calculating the average value of the remaining capacity of the plurality of energy storage devices; and S3: subtracting the average value calculated in step S2 from the remaining capacity of each of the energy storage devices to obtain a difference value; if the difference value is greater than 0, increasing the output voltage of the corresponding energy storage device to increase the output power of the energy storage device; and if the difference value is less than 0, decreasing the output voltage of the corresponding energy storage device to reduce the output power of the energy storage device.

[0008] Furthermore, step S3 specifically determines the remaining capacity (SOC) of the i-th energy storage device. i Therefore, the average SOC calculated in step S2 ave The difference value is obtained by subtracting the value, and the corresponding output voltage on the energy storage device side is set to the target voltage value U iRef This includes adjusting the output power of the energy storage device by adjusting the target voltage value to U iRef =U rated +ΔU i U rated ΔU is the rated voltage of the energy storage device, i This is a target voltage adjustment value calculated based on the difference value, where i = 1 to n, and n is the number of energy storage devices.

[0009] Furthermore, the calculation formula for the target voltage adjustment value is ΔU i =(SOC i -SOC ave )×U rated .

[0010] Furthermore, after step S3, it further includes a step of repeating steps S1 to S3 until the remaining capacities of all the energy storage devices become equal.

[0011] Furthermore, step S3 specifically includes subtracting the average value SOC i_j calculated in step S2 from the remaining capacity SOC ave of the i-th energy storage device to obtain the difference value, and adjusting the output voltage on the corresponding energy storage device side to the step target voltage value U<00…… (The text seems to be incomplete here. It might be better to double-check the original text for accuracy. But this is the translation based on what's provided so far.) iRef_j iRef_j =U rated +ΔU i_j , where U rated is the rated voltage of the energy storage device, and ΔU i_j is the target voltage adjustment value at the j-th voltage adjustment for the i-th energy storage device calculated based on the difference value, where i = 1 to n, n is the number of the energy storage devices, and j is the number of the current voltage adjustment.

[0012] Furthermore, the calculation formula for the target voltage adjustment value at the j-th voltage adjustment for the i-th energy storage device is ΔU i_j =ΔU SOC_i_j *r2 i +ΔU p_i_j *r3 i . Here, ΔU SOC_i_j is the first target voltage adjustment value at the j-th voltage adjustment for the i-th energy storage device calculated based on the difference value, and ΔU p_i_jr2 is a second target voltage adjustment value for the jth voltage adjustment of the i-th energy storage device, calculated based on the change in the AC-side output power of the i-th energy storage device, and r2 i and r3 i is the weight, and r2 i +r3 i = 1

[0013] Furthermore, the formula for calculating the first target voltage adjustment value during the jth voltage adjustment for the i-th energy storage device is ΔU SOC_i_j =(SOC i_j -SOC ave )×U rated ×r1 i and r1 i This is the proportionality constant.

[0014] Furthermore, r1 i It takes a value between 10% and 20%.

[0015] Furthermore, the formula for calculating the second target voltage adjustment value during the jth voltage adjustment for the i-th energy storage device is ΔU p_i_j =K u_i_j *ΔU SOC_i_j And here, K u_i_j is the power change ratio during the jth voltage adjustment for the i-th energy storage device, and K u_i_j =(P m_i_j -P m_k0_i_j ) / P mMean_i_j And in the formula, P m_i_j P is the AC output power during the jth voltage adjustment for the i-th energy storage device, and P mMean_i_j P is the periodic average value of the AC side output power during the jth voltage adjustment for the i-th energy storage device, calculated using sliding window filtering, and P m_k0_i_j This is the power value removed from the sliding window filter during the jth voltage adjustment for the i-th energy storage device.

[0016] In a second aspect, the present invention discloses a multiphase AC system comprising energy storage devices, wherein the system comprises a plurality of energy storage devices and a system load, the plurality of energy storage devices are communicated with one another, the live lines on the AC output side of the plurality of energy storage devices are each connected to the system load, the neutral lines of the plurality of energy storage devices are connected to a common point of the neutral lines of the system load, and the energy storage devices are subjected to energy equalization control by employing the energy equalization control method described in the first aspect.

[0017] Furthermore, the multiphase AC system comprising the energy storage devices further comprises at least one standalone load, and the standalone load is independently connected to the AC output side of at least one of the plurality of energy storage devices.

[0018] Furthermore, prior to step S1, the method further includes a step of connecting multiple energy storage devices via communication and assigning master and slave roles such that one of the multiple energy storage devices is identified as the master and the other energy storage devices are identified as slaves.

[0019] Furthermore, the master is used to transmit a power frequency phase signal to the slave at the zero-crossing point in the master's power frequency cycle, to acquire the remaining capacity of the plurality of energy storage devices, and to acquire a target voltage value for each energy storage device and transmit it to the corresponding slave using the power equalization control method described in the first embodiment.

[0020] Furthermore, the slave is used to acquire and track the power frequency phase signal transmitted from the master, and to control the slave's power frequency phase so that it lags behind the master's power frequency phase.

[0021] Furthermore, there are two of the energy storage devices, the multiphase AC system consisting of the energy storage devices is a split-phase two-wire system, and the power supply frequency phase of the slave lags the power supply frequency phase of the master by 180°.

[0022] Furthermore, the number of energy storage devices is three, the multiphase AC system consisting of the energy storage devices is a three-phase four-wire system, the number of slaves is two, and the power frequency phases between the three energy storage devices are shifted by 120°.

[0023] In a third aspect, the present invention discloses a storage medium storing a computer program that is executed by a processor and configured to perform the power equalization control method described in the first aspect.

[0024] The beneficial effects of comparing the present invention with the prior art are as follows: According to the multiphase AC system consisting of energy storage devices and the power equalization control method thereof proposed in the present invention, by adjusting the output voltage of each energy storage device according to the remaining capacity status of each energy storage device and thereby adjusting the output power of the energy storage devices, active power equalization control of the multiphase AC system consisting of energy storage devices is realized, and the problem of shortened system load duration caused by SOC mismatch is effectively solved.

[0025] Further measures involve adjusting the output voltage of each energy storage device in stages and increments according to the remaining capacity of each energy storage device to adjust the output power of the energy storage devices. By considering the stability of each individual load with each output voltage adjustment and adjusting the output voltage of each energy storage device in stages and increments using a cyclic adjustment method, fluctuations in individual load power are prevented, ensuring that individual loads operate and are used normally under rated voltage and within a certain voltage fluctuation range, and further stabilizing the system. This avoids discrepancies in the power consumption of each energy storage device that constitutes the system, matches the battery life of each energy storage device, and ensures that each type of electrical equipment operates and is used normally under rated voltage and within a certain voltage fluctuation range. It also avoids operating each individual load under conditions of excessively high or low voltage, significantly extending the lifespan of the electrical equipment, reducing energy consumption, minimizing the possibility of damage to the electrical equipment, and ensuring electrical safety. [Brief explanation of the drawing]

[0026] [Figure 1] This is a flowchart of a power equalization control method for a multiphase AC system comprising an energy storage device disclosed in Example 1 of the present invention. [Figure 2] This is a block diagram of a preferred embodiment 1 of the present invention, which is a two-phase split-wire system. [Figure 3] This is a flowchart of the master-slave phase control of a split-phase two-wire system according to a preferred embodiment 1 of the present invention. [Figure 4] This is a schematic diagram showing how output power is adjusted to equalize the State of Charge (SOC) in a split-phase two-wire system according to a preferred embodiment 1 of the present invention. [Figure 5] This is a control flowchart for adjusting the output voltage to equalize the State of Control (SOC) in a split-phase two-wire system according to a preferred embodiment 1 of the present invention. [Figure 6] This is a block diagram of a preferred embodiment 1 of the present invention, which is a three-phase four-wire system. [Figure 7]This is a flowchart of a power equalization control method for a multiphase AC system comprising an energy storage device disclosed in Example 2 of the present invention. [Figure 8] This is a block diagram of a preferred embodiment 2 of the present invention, which is a two-phase split-wire system. [Figure 9] This is a schematic diagram illustrating how output power is adjusted to equalize the State of Charge (SOC) in a split-phase two-wire system according to a preferred embodiment 2 of the present invention. [Figure 10] This is a control flowchart for adjusting the output voltage to equalize the State of Control (SOC) in a split-phase two-wire system according to a preferred embodiment 2 of the present invention. [Figure 11] This is a block diagram of a preferred embodiment 2 of the present invention, which is a three-phase four-wire system. [Modes for carrying out the invention]

[0027] Embodiments of the present invention will be described in detail below. Please note that the following description is illustrative and not intended to limit the scope or uses of the present invention.

[0028] Furthermore, when a component is said to be "fixed" or "installed" to another component, this component may be located directly or indirectly to the other component. When a component is said to be "connected" to another component, this component may be directly connected to the other component or indirectly connected to the other component. Also, a connection may be for fixing purposes or for conducting circuits or signals.

[0029] It should be understood that the directions and positional relationships indicated by terms such as "length," "width," "top," "bottom," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside" are based on the directions and positional relationships shown in the drawings and are intended solely to facilitate and simplify the explanation of embodiments of the present invention. They do not indicate or suggest that the indicated devices or components must be in a specific direction, or that they must be configured and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0030] In addition, the terms “first” and “second” are used solely for descriptive purposes and should not be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical feature. Thus, the features limited by “first” and “second” may explicitly or implicitly include one or more such features. In the description of embodiments of the present invention, “multiple” means two or more unless particularly explicitly and specifically limited. [Examples]

[0031] Embodiment 1 of the present invention discloses a power equalization control method for a multiphase AC system consisting of energy storage devices, as shown in Figure 1, which includes the steps of: S1: obtaining the remaining capacity of a plurality of energy storage devices; S2: calculating the average value of the remaining capacity of the plurality of energy storage devices; and S3: obtaining a difference value by subtracting the average value calculated in step S2 from the remaining capacity of each energy storage device, and if the difference value is greater than 0, increasing the output voltage of the corresponding energy storage device to increase the output power of the energy storage device, and if the difference value is less than 0, decreasing the output voltage of the corresponding energy storage device to reduce the output power of the energy storage device.

[0032] In that context, step S3 specifically involves the remaining capacity (SOC) of the i-th energy storage device. i Therefore, the average SOC calculated in step S2 ave Subtract the difference to find the corresponding output voltage U on the energy storage device side.i Target voltage value U iRef This includes adjusting the output power of the energy storage device by adjusting the target voltage value U iRef =U rated +ΔU i U rated This is the rated voltage of the energy storage device, and ΔU i This is the target voltage adjustment value calculated based on the difference value, where i = 1 to n, and n is the number of energy storage devices. Furthermore, the formula for calculating the target voltage adjustment value is ΔU i =(SOC i -SOC ave )×U rated That is the case.

[0033] Embodiment 1 of the present invention also discloses a multiphase AC system comprising energy storage devices, wherein the system comprises a plurality of energy storage devices and a system load, the plurality of energy storage devices are communicated with one another, the live lines on the AC output side of the plurality of energy storage devices are each connected to the system load, the neutral lines of the plurality of energy storage devices are connected to a common point of the neutral lines of the system load, and the energy storage devices are subjected to energy equalization control by employing the energy equalization control method described in the above embodiment.

[0034] However, prior to step S1, the method further includes the step of connecting multiple energy storage devices to each other and assigning master and slave roles such that one of the energy storage devices is identified as the master and the others as slaves. Furthermore, the master is used to transmit a power frequency phase signal to the slaves at the zero-crossing point in the master's power frequency period, to acquire the remaining capacity of the multiple energy storage devices, and to acquire and transmit target voltage values ​​for each energy storage device to the corresponding slaves using the power equalization control method described in the above embodiment. The slaves are used to acquire and track the power frequency phase signal transmitted from the master and to control the slave's power frequency phase to lag behind the master's power frequency phase.

[0035] In some embodiments, the number of energy storage devices is two, and the multiphase AC system consisting of the energy storage devices is a split-phase two-wire system, where the power frequency phase of the slave lags the power frequency phase of the master by 180°. In other embodiments, the multiphase AC system of the energy storage devices is a three-phase four-wire system, the number of slaves is two, and the power frequency phases between the three energy storage devices are each shifted by 120°.

[0036] Embodiment 1 of the present invention also discloses a storage medium characterized by storing a computer program that is executed by a processor and configured to perform the power equalization control method described in Embodiment 2 above.

[0037] Optionally, the above storage media may include, but are not limited to, various media capable of storing computer programs, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0038] Next, a multiphase AC system comprising the energy storage device proposed in Embodiment 1 of the present invention and its power equalization control method will be further described using specific preferred embodiments.

[0039] Embodiment 1 of the present invention is preferably a split-phase two-wire system, which is a split-phase L1-N-L2 AC power supply system configured such that two independent energy storage power supplies are connected in series on the AC output side, the AC output phase difference is 180°, and a neutral wire is connected. This split-phase two-wire system can achieve doubling of the output AC voltage.

[0040] Specifically, as shown in Figure 2, the split-phase two-wire system comprises two energy storage power sources, a first energy storage power source 11 and a second energy storage power source 12, capable of outputting AC in an off-grid state, and a system load 20 (in this embodiment, the system load is a two-live-line load). The first energy storage power source 11 and the second energy storage power source 12 are connected via a communication connection, and the neutral wires (N) on the AC output side of the first energy storage power source 11 and the second energy storage power source 12 are connected to the common point of the neutral wires of the system load 20. The live wire (L1) of the first energy storage power source 11 and the live wire (L2) of the second energy storage power source 12 are each individually connected to the system load 20.

[0041] In the split-phase two-wire system, the output voltage U1 of the first energy storage power supply 11 and the output voltage U2 of the second energy storage power supply 12 at the initial point of output are both the rated AC output voltage value U rated (100Vac or 120Vac).

[0042] Furthermore, the power equalization control method for the split-phase two-wire system includes the following steps.

[0043] A1: Master and slave assignment The specific procedure for assigning master and slave roles includes the following: As shown in Figure 3, two independent energy storage power supplies are connected via communication, and after assigning master and slave roles in a competitive manner, it is determined whether the unit is the master. If it is the master, the current remaining capacity SOC of this unit is determined. m and the slave's current remaining capacity SOC s Obtain the target voltage value U of the master mRef and the slave's target voltage value U sRef Calculate the target voltage value U corresponding to the slave. sRefIn addition to transmitting, the slave receives a phase-lock signal at the master's zero-crossing point, and if it is not the master, it obtains the master's current output power frequency phase Thetam to track the master's phase and control the slave's phase to lag it 180 degrees behind the master, and the target voltage value U of this unit transmitted from the master. sRef Obtain it.

[0044] In this specific embodiment, a first energy storage power source 11 and a second energy storage power source 12, which are independent of each other, are connected by communication and are automatically assigned to compete as masters, with one being identified as the master and the other as the slave. In this embodiment, as an example, when the first energy storage power source 11 is assigned as the master and the second energy storage power source 12 is assigned as the slave, U m =U1=U rated , U s =U2=U rated Here, U1 is the output voltage of the first energy storage power source 11, U2 is the output voltage of the second energy storage power source 12, U m The master output voltage is U s The output voltages of the slaves are shown, and the output voltages of both the master and slaves are initially both the rated AC output voltage value U rated It is equivalent to this. Among them, the master is the remaining capacity SOC of this device. m and the slave's current remaining capacity SOC s Obtain the target voltage value U of the master mRef and the slave's target voltage value U sRef Calculate the target voltage value U corresponding to the slave. sRef In addition to transmitting signals, it is also used to transmit a power frequency phase signal to the slave at the point of zero-crossing in the master's power frequency cycle. The slave then acquires and tracks the power frequency phase signal transmitted from the master, and controls the slave's output phase so that it is shifted by 180° from the master's.

[0045] In some embodiments, it is also possible to assign master and slave roles to each energy storage power supply using methods other than those described above. For example, by providing a single control unit to one energy storage device, that energy storage device (i.e., the energy storage power supply in this embodiment) can be designated as the master, and the other energy storage devices as slaves. In the above embodiments, only one slave is mentioned, but when there are multiple slaves, any existing slave address assignment method may be used for assigning the slave addresses. For example, 1) a method in which address assignment is completed through free competition, 2) a method in which a DIP switch is installed on each slave to set the address, 3) a method in which the address of each slave is set using a keyboard or human interface, 4) a method in which the address of each slave is set using serial port software on a computer, and 5) a method in which the slave checks the bus status, waits for an idle state, and then repeatedly communicates with the master, and when a station number conflict occurs, the address is reassigned.

[0046] A2: Obtain the remaining capacity of multiple energy storage power sources, calculate the average value of the remaining capacities of the multiple energy storage power sources, and then subtract the average value from the remaining capacity of each energy storage power source to find the difference value. If the difference value is greater than 0, increase the output voltage of the corresponding energy storage power source to increase its output power. If the difference value is less than 0, decrease the output voltage of the corresponding energy storage power source to reduce its output power.

[0047] In this specific embodiment, the difference in remaining capacity between two energy storage power sources is directly obtained, and power equalization and output voltage control are performed depending on whether the difference is greater than or less than 0. Specifically, as shown in Figure 4, the master obtains the current SOC difference between the master and the slave, and calculates ΔSOC = SOC. m -SOC s The system calculates the current SOC difference value ΔSOC and enters the power equalization-output voltage control mode accordingly.

[0048] (1) When the master determines that the current ΔSOC > 0, it indicates that the current power of the master is higher than that of the slave. By increasing the output power of the master and reducing the output power of the slave, SOC equalization can be achieved.

[0049] (2) When the master determines that the current ΔSOC < 0, it indicates that the current power of the master is lower than that of the slave. By reducing the output power of the master and increasing the output power of the slave, SOC equalization can be achieved.

[0050] The line voltage U between the output ports of the system load 20 LL (L1 - L2 line voltage) is the sum U of the master output voltage U m and the slave output voltage Us LL = U m + U s That is. In order to ensure the stabilization of the loaded output, for this split - phase two - wire system, the line voltage U LL is kept constant, that is, U rated which is twice the rated voltage U LL = U rated *2 is controlled to be maintained. Therefore, the total output voltage of this split - phase two - wire system composed of two independent energy storage power sources is U m + U s = U rated *2 and is kept constant. Further, in this split - phase two - wire system, since the two energy storage power sources are connected in series on the AC output side, the AC side currents of the two energy storage power sources are equal, that is, I m = I s where I m is the current of the master (i.e., the first energy storage power source 11), and I s is the current of the slave (i.e., the second energy storage power source 12).

[0051] Since the output currents of the two energy storage power sources in this split - phase two - wire system are equal, adjusting the output power of the energy storage power source is achieved by adjusting the AC output voltage. For example, the output power P of the master mIf it is necessary to increase P m =U m Base I m Based on this, the output voltage U of the current energy storage power supply m The corresponding target voltage value U mRef :U mRef =U rated It is necessary to raise it to +ΔU, and furthermore, the output line voltage of the split-phase two-wire system is U LL =U rated *2=U m +U s Therefore, since the output line voltage of the system load 20 is kept constant, when the output voltage of the master rises, the output voltage of the slave is lowered (current energy storage power output voltage U s The corresponding target voltage value U sRef It is necessary to lower it to U sRef =U rated -ΔU, P s =U s Base I s Based on this, the slave's output power is reduced.

[0052] As shown in Figure 5, when ΔSOC > 0, the master output voltage is U m =U mRef =U rated Increase +ΔU and set the slave's output voltage to U s =U sRef =U rated -ΔU is reduced, and the master output power P m Further increasing the slave output power P s By further reducing this, SOC equalization is achieved. When ΔSOC < 0, the master output voltage is set to U m =U mRef =U rated -ΔU is reduced, and the slave output voltage is U s =U sRef =U rated Increase +ΔU to master output power P m Further reducing the slave's output power P s By further increasing this, we will achieve SOC equalization.

[0053] Master target voltage value U mRef and the slave's target voltage value U sRef By dynamically adjusting the master output frequency P m and the slave's output frequency P s This enables dynamic adjustment and further adjusts the battery discharge rate in the energy storage power supply, thereby actively equalizing the State of Charge (SOC) of the two energy storage power supplies.

[0054] In this case, the target voltage adjustment value is ΔU = (ΔSOC / 2) * U rated And here, SOC m SOC s Both ΔSOC and ΔSOC are numbers between 0 and 1, and when expressed as a percentage, for example, the master SOC m 80% is the slave SOC s The percentage is 50%, and the ΔSOC is 30%.

[0055] Embodiment 1 of the present invention is also preferably a three-phase four-wire system, which is a three-phase AC power supply system configured such that three independent energy storage power sources are connected in a star configuration to the AC output side, the phases of the AC outputs are shifted by 120° from each other, and a neutral wire is connected.

[0056] Specifically, as shown in Figure 6, the three-phase four-wire system comprises three energy storage power sources: a first energy storage power source 11, a second energy storage power source 12, and a third energy storage power source 13, all capable of outputting AC in an off-grid state, and a system load 20 (in this embodiment, the system load is a three-phase load). The first energy storage power source 11, the second energy storage power source 12, and the third energy storage power source 13 are connected via communication, and the neutral wires (N) on the AC output side of the first energy storage power source 11, the second energy storage power source 12, and the third energy storage power source 13 are connected to the common point of the neutral wires of the system load 20. The live wire (L1) of the first energy storage power source 11, the live wire (L2) of the second energy storage power source 12, and the live wire (L3) of the third energy storage power source 13 are each individually connected to the system load 20.

[0057] In the three-phase four-wire system, the output voltage U1 of the first energy storage power supply 11, the output voltage U2 of the second energy storage power supply 12, and the output voltage U3 of the third energy storage power supply 13 are all initially at their rated AC output voltage values ​​U rated (100Vac or 120Vac).

[0058] Furthermore, the power equalization control method for the three-phase four-wire system includes the following steps.

[0059] B1: Master and Slave Assignment The specific procedure for assigning master and slave roles involves connecting three independent energy storage power sources via communication, automatically assigning master and slave roles in a competitive manner, identifying one energy storage power source as the master, and the other two as slaves. The specific procedure for assigning master and slave roles in this three-phase four-wire system differs from a split-phase two-wire system only in that the phases of the master and slaves are shifted by 120°; the other specific procedures are the same, so no further explanation is needed here.

[0060] B2: Obtain the remaining capacity of multiple energy storage power sources, calculate the average value of the remaining capacities of the multiple energy storage power sources, and then subtract the average value from the remaining capacity of each energy storage power source to find the difference value. If the difference value is greater than 0, increase the output voltage of the corresponding energy storage power source to increase its output power. If the difference value is less than 0, decrease the output voltage of the corresponding energy storage power source to reduce its output power.

[0061] In this specific embodiment, the master acquires the remaining capacities SOC1, SOC2, and SOC3 of each energy storage power source, the master and slaves are out of phase by 120°, and the total output voltage of the three-phase four-wire system consisting of three independent energy storage power sources is kept constant.

[0062] The average State of Charge (SOC) of the three energy storage power sources is the SOCave = (SOC1 + SOC2 + SOC3) / 3 is used to calculate the SOC of each current energy storage power source. i (i=1, 2, 3) and SOC ave Compare and SOC i SOC ave If it is equal to, there is no need to increase or decrease the output power, SOC i <SOC ave In this case, the output power is reduced, SOC i >SOC ave In this case, the output power is increased.

[0063] Since the total output voltage is maintained constant and the three-phase load does not change, the total current I does not change. Therefore, the present invention further increases or decreases the output power of each energy storage power supply by adjusting the voltage of each energy storage power supply. In this case, the output voltage U1 of the first energy storage power supply 11 is set to the corresponding target voltage value U 1Ref =U rated Adjust to +ΔU1, and set the output voltage U2 of the second energy storage power supply 12 to the corresponding target voltage value U 2Ref =U rated Adjust to +ΔU2, and set the output voltage U3 of the third energy storage power supply 13 to the corresponding target voltage value U 3Ref =U rated Adjust to +ΔU3, where ΔU1 + ΔU2 + ΔU3 = 0. Target voltage adjustment value ΔU i If (i=1, 2, 3) is 0, the remaining capacity (SOC) of the corresponding energy storage power source. i =SOC ave This indicates that there is no need to increase or decrease the output power, ΔU i If negative, the SOC of the corresponding energy storage power source. i <SOC ave This indicates that the output power needs to be reduced, ΔU i If positive, the SOC of the corresponding energy storage power source. i >SOC ave This indicates that the output power needs to be increased.

[0064] In this case, the formula for calculating the target voltage adjustment value is ΔU i =(SOCi -SOC ave )×U rated And i = 1, 2, 3, U rated This is the rated voltage of the energy storage power supply. Here, SOC i SOC ave These are all numbers between 0 and 1, and when expressed as percentages, for example, the remaining capacity SOC1 of the first energy storage power source 11 is 80%, the remaining capacity SOC2 of the second energy storage power source 12 is 50%, and the remaining capacity SOC3 of the third energy storage power source 13 is 30%. ave That is 53.3%.

[0065] According to the power equalization control method proposed in Preferred Embodiment 1 of the present invention, the two-wire split-phase system and the four-wire three-phase system are controlled to maintain a constant output line voltage, thereby providing stable power support to the load. Furthermore, in real time, the output voltage of a single energy storage power supply is adjusted according to the remaining capacity (SOC) and load power status of each energy storage power supply, thereby increasing the loaded output power of energy storage power supplies with high energy capacity while decreasing the loaded output power of energy storage power supplies with low energy capacity. This enables active power equalization control of the two-wire split-phase system and the four-wire three-phase system, effectively solving the problem of reduced system load duration caused by mismatches in remaining capacity (SOC). [Examples]

[0066] Each country and region has its own unique voltage specifications for its grid, with common voltages being 110V, 220V, and 240V. Some countries have multiple voltage specifications; for example, in the United States, single-phase, single-phase three-wire, and three-phase power supply systems are all very common, resulting in single-phase power (120V), two-live-line output (240V), and three-phase power (208V). Among these, single-phase power (120V) provides a constant alternating current that flows in one direction and has the form of a single sinusoidal wave, and is used for small household loads such as lighting, heating, and small electrical appliances. Two-live-line output (240V) is used for heavy electrical equipment such as air conditioners, electric heaters, and washing machines, reducing energy loss due to heat by transmitting large electrical equipment loads with the lower current, and two-live-line output is also commonly used in industrial and commercial places. China employs a three-phase four-wire power system, with household power typically at 220V, while factory power is typically at 380V. Depending on these voltage specifications and power supply methods, the operating voltage of electrical equipment (i.e., loads) typically varies, ranging from 120V to 240V and even 380V.

[0067] A two-live-line AC system consisting of two independent energy storage power sources, or a three-phase AC system consisting of three independent energy storage power sources, can meet the different operating voltage requirements of different electrical equipment loads. By integrating multiple energy storage power sources into a single system and outputting them together (including two-live-line output and three-phase power output), power can be supplied to system loads requiring high voltage. On the other hand, each energy storage power source can also supply power to single-phase loads (also called standalone loads) requiring low voltage while maintaining its own rated voltage single-phase power output.

[0068] In a multiphase AC system consisting of multiple energy storage power sources, if the battery of any one of the energy storage power sources completely discharges, the system will shut down because it will no longer be able to handle the 2-live line output or 3-phase power output. In particular, if a single energy storage power source has a single load connected to it, or if the single loads are unevenly distributed among the multiple energy storage power sources, the power consumption of each energy storage power source constituting the system becomes more uneven. The energy storage power source with the higher single load power will have a shorter battery life and will completely discharge faster than the energy storage power source with the lower single load power. On the other hand, since various electrical equipment can only operate and be used normally under rated voltage and within a certain voltage fluctuation range, if the fluctuation of the AC output voltage of each single energy storage power source exceeds the allowable range, each single load will operate under conditions of excessively high or excessively low voltage, directly shortening the lifespan of the electrical equipment, increasing energy consumption, increasing the possibility of damage to the electrical equipment, and ultimately threatening electrical safety.

[0069] Embodiment 2 of the present invention discloses a power equalization control method for a multiphase AC system consisting of energy storage devices, which further considers the lifespan and electrical safety issues of individual loads and the stability of the system, in order to effectively solve the problem of shortened system load duration caused by mismatch in remaining capacity (SOC), as shown in Figure 7, and includes the steps of: S1: obtaining the remaining capacity of a plurality of energy storage devices; S2: calculating the average value of the remaining capacities of the plurality of energy storage devices; S3: obtaining a difference value by subtracting the average value calculated in step S2 from the remaining capacity of each energy storage device, increasing the output voltage of the corresponding energy storage device to increase the output power of the energy storage device if the difference value is greater than 0, and decreasing the output voltage of the corresponding energy storage device to reduce the output power of the energy storage device if the difference value is less than 0; and repeating steps S1 to S3 until the remaining capacities of each energy storage device are all equal.

[0070] In that context, step S3 specifically involves the remaining capacity (SOC) of the i-th energy storage device. i_j Therefore, the average SOC calculated in step S2ave Subtract the difference to obtain the difference value, and set the corresponding output voltage on the energy storage device side to the step target voltage value U iRef_j This includes adjusting the output power of the energy storage device by adjusting the step target voltage value U iRef_j =U rated +ΔU i_j U rated This is the rated voltage of the energy storage device, and ΔU i_j is the target voltage adjustment value for the jth voltage adjustment for the i-th energy storage device, calculated based on the difference value, where i = 1 to n, n is the number of energy storage devices, and j is the current voltage adjustment number.

[0071] Furthermore, the formula for calculating the target voltage adjustment value for the jth voltage adjustment for the i-th energy storage device is ΔU i_j =ΔU SOC_i_j *r2 i +ΔU p_i_j *r3 i And here, ΔU SOC_i_j This is the first target voltage adjustment value for the jth voltage adjustment for the i-th energy storage device, calculated based on the difference value, and ΔU p_i_j r2 is the second target voltage adjustment value for the jth voltage adjustment for the i-th energy storage device, calculated based on the change in the AC output power of the i-th energy storage device, and r2 i and r3 i is the weight, and r2 i +r3 i = 1. Within this, the formula for calculating the first target voltage adjustment value during the jth voltage adjustment for the i-th energy storage device is ΔU SOC_i_j =(SOC i_j -SOC ave )×U rated ×r1 i and r1 i This is the proportionality constant. Specifically, r1 i It takes a value of 10% to 20%. Among these, the formula for calculating the second target voltage adjustment value during the jth voltage adjustment for the i-th energy storage device is ΔU p_i_j =K u_i_j *ΔU SOC_i_jAnd here, K u_i_j is the power change ratio during the jth voltage adjustment for the i-th energy storage device, and K u_i_j =(P m_i_j -P m_k0_i_j ) / P mMean_i_j And in the formula, P m_i_j P is the AC output power during the jth voltage adjustment for the i-th energy storage device, and P mMean_i_j P is the periodic average value of the AC side output power during the jth voltage adjustment for the i-th energy storage device, calculated using sliding window filtering, and P m_k0_i_j This is the power value removed from the sliding window filter during the jth voltage adjustment for the i-th energy storage device.

[0072] Embodiment 2 of the present invention also discloses a multiphase AC system comprising energy storage devices, wherein the system comprises a plurality of energy storage devices, a system load, and at least one individual load, the plurality of energy storage devices are communicated with each other, the live lines on the AC output side of each of the plurality of energy storage devices are connected to the system load, the neutral lines of the plurality of energy storage devices are connected to the common point of the neutral lines of the system load, and at least one of the plurality of energy storage devices has an individual load independently connected to its AC output side, and the energy storage device system employs the energy equalization control method described in Embodiment 2 above to perform energy equalization control on the plurality of energy storage devices. The individual load is a single-phase load connected to each independent energy storage power source, and each energy storage power source consumes the energy of its own battery due to its individual load.

[0073] However, prior to step S1, the method further includes the step of connecting multiple energy storage devices via communication and assigning master and slave roles such that one of the energy storage devices is identified as the master and the others as slaves. Furthermore, the master is used to transmit a power frequency phase signal to the slaves at the zero-crossing point in the master's power frequency period, to acquire the remaining capacity of the multiple energy storage devices, and to acquire and transmit the target voltage value of each energy storage device to the corresponding slave using the power equalization control method described in Embodiment 2 above. The slaves are used to acquire and track the power frequency phase signal transmitted from the master and to control the slave's power frequency phase to lag behind the master's power frequency phase.

[0074] In some embodiments, there are two energy storage devices, and the multiphase AC system consisting of the energy storage devices is a split-phase two-wire system, with a power frequency phase difference of 180° between the two energy storage devices. In other embodiments, there are three energy storage devices, and the multiphase AC system consisting of the energy storage devices is a three-phase four-wire system, with a power frequency phase difference of 120° between each of the three energy storage devices.

[0075] Embodiment 2 of the present invention also discloses a storage medium characterized by storing a computer program that is executed by a processor and configured to perform the power equalization control method described in Embodiment 2 above.

[0076] Optionally, the above storage media may include, but are not limited to, various media capable of storing computer programs, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0077] Next, a multiphase AC system comprising the energy storage device proposed in Embodiment 2 of the present invention and a method for controlling its power equalization will be further described using specific preferred embodiments.

[0078] Embodiment 2 of the present invention is preferably a split-phase two-wire system, which is a split-phase L1-N-L2 AC power supply system configured such that two independent energy storage power supplies are connected in series on the AC output side, the AC output phase difference is 180°, and a neutral wire is connected. The split-phase two-wire system can achieve doubling of the output AC voltage.

[0079] Specifically, as shown in Figure 8, the split-phase two-wire system comprises two energy storage power sources, a first energy storage power source 11 and a second energy storage power source 12, capable of outputting AC in an off-grid state, a system load 20 (in this embodiment, the system load is a two-live-line load), a first single-unit load 31, and a second single-unit load 32. The first energy storage power source 11 and the second energy storage power source 12 are connected via a communication connection, and the neutral wires (N) on the AC output sides of the first energy storage power source 11 and the second energy storage power source 12 are connected to a common point of the neutral wires of the system load 20. The live wire (L1) of the first energy storage power source 11 and the live wire (L2) of the second energy storage power source 12 are individually connected to the system load 20, and the AC output side of the first energy storage power source 11 is connected to the first single-unit load 31, and the AC output side of the second energy storage power source 12 is connected to the second single-unit load 32.

[0080] In the split-phase two-wire system, the output voltage U1 of the first energy storage power supply 11 and the output voltage U2 of the second energy storage power supply 12 at the initial point of output are both the rated AC output voltage value U rated (100Vac or 120Vac).

[0081] Furthermore, the power equalization control method for the split-phase two-wire system includes the following steps.

[0082] C1: Master and Slave Assignment The specific procedure for assigning master and slave in this embodiment is the same as the specific procedure for assigning master and slave in Embodiment 1, and includes the following: As shown in Figure 3, two independent energy storage power supplies are connected via communication, and after assigning master and slave in a competitive manner, it is determined whether it is the master or not, and if it is the master, the current remaining capacity SOC of this unit is determined. m and the slave's current remaining capacity SOC s Obtain the target voltage value U of the master mRef and the slave's target voltage value U sRef Calculate the target voltage value U corresponding to the slave. sRef In addition to transmitting, the slave receives a phase-lock signal at the master's zero-crossing point, and if it is not the master, it obtains the master's current output power frequency phase Thetam to track the master's phase and control the slave's phase to lag it 180 degrees behind the master, and the target voltage value U of this unit transmitted from the master. sRef Obtain it.

[0083] In this specific embodiment, a first energy storage power source 11 and a second energy storage power source 12, which are independent of each other, are connected by communication and are automatically assigned to compete as masters, with one being identified as the master and the other as the slave. In this embodiment, as an example, when the first energy storage power source 11 is assigned as the master and the second energy storage power source 12 is assigned as the slave, U m =U1=U rated , U s =U2=U rated Here, U1 is the output voltage of the first energy storage power source 11, U2 is the output voltage of the second energy storage power source 12, U m The master output voltage is U s The output voltages of the slaves are shown, and the output voltages of both the master and slaves are initially both the rated AC output voltage value U rated It is equivalent to this. Among them, the master is the remaining capacity SOC of this device. m and the slave's current remaining capacity SOC sObtain the target voltage value U of the master mRef and the slave's target voltage value U sRef Calculate the target voltage value U corresponding to the slave. sRef In addition to transmitting the power supply frequency phase signal, it is also used to transmit the power supply frequency phase signal to the slave at the zero-crossing point in the master's power supply frequency cycle. The slave acquires and tracks the power supply frequency phase signal transmitted from the master, and controls the slave's output phase so that it is shifted by 180° from the master, and the target voltage value U of the unit transmitted from the master is transmitted to the slave. sRef It is used to obtain [something].

[0084] In some embodiments, it is also possible to assign master and slave roles to each energy storage power supply using methods other than those described above. For example, by providing one control unit to a single energy storage device, that energy storage device can be designated as the master and the other energy storage devices as slaves. In the above embodiments, only one slave is mentioned, but when there are multiple slaves, any existing slave address assignment method may be used for assigning the slave addresses. For example, 1) a method in which address assignment is completed through free competition, 2) a method in which a DIP switch is installed on each slave to set the address, 3) a method in which the address of each slave is set using a keyboard or human interface, 4) a method in which the address of each slave is set using serial port software on a computer, and 5) a method in which the status of the bus is checked via the slave, and communication with the master is repeatedly performed after waiting for an idle state, and the address is reassigned when a station number conflict occurs.

[0085] C2: Obtain the remaining capacity of multiple energy storage power sources, calculate the average value of the remaining capacities of the multiple energy storage power sources, then subtract the average value from the remaining capacity of each energy storage power source to find the difference value. If the difference value is greater than 0, increase the output voltage of the corresponding energy storage power source to increase its output power. If the difference value is less than 0, decrease the output voltage of the corresponding energy storage power source to reduce its output power. Repeat the above until the remaining capacities of all energy storage power sources are equal.

[0086] In this specific embodiment, the difference in remaining capacity between two energy storage power sources is directly obtained, and power equalization and output voltage control are performed depending on whether the difference is greater than or less than 0. Specifically, as shown in Figure 9, the master uses the current SOC difference between the master and the slave as ΔSOC=SOC. m -SOC s The system calculates the current SOC difference value ΔSOC and enters the power equalization-output voltage control mode accordingly.

[0087] (1) When the master determines that the current ΔSOC > 0, it indicates that the current power of the master is higher than the power of the slave. Therefore, the master's output power is gradually increased and the slave's output power is gradually decreased to equalize the SOC.

[0088] (2) When the master determines that the current ΔSOC < 0, it indicates that the current power of the master is lower than the power of the slave. SOC equalization is achieved by gradually reducing the output power of the master and gradually increasing the output power of the slave.

[0089] Line voltage U at the output port of system load 20 LL (Voltage between L1 and L2 lines) is the master output voltage U m and the sum of the slave output voltage Us U LL =U m +U s This split-phase two-wire system ensures stable output under load by reducing the line voltage U across the output port. LL It remains constant, i.e., the rated voltage Urated U is twice the amount of LL =U rated Controlled to maintain *2. Therefore, the total output voltage of the split-phase two-wire system consisting of two independent energy storage power sources is U m +U s =U rated *2 is maintained at a constant value. Furthermore, in this split-phase two-wire system, since the two energy storage power supplies are connected in series on the AC output side, the AC currents of the two energy storage power supplies are equal, i.e., I m =I s And I m is the current of the master (i.e., the first energy storage power source 11), and I s This is the current of the slave (i.e., the second energy storage power source 12).

[0090] In this split-phase two-wire system, since the output currents of the two energy storage power supplies are equal, adjusting the output power of the energy storage power supplies is achieved by adjusting the AC output voltage. For example, the output power P of the master m If it is necessary to increase P m =U m Base I m Based on this, the output voltage U of the current energy storage power supply m The corresponding target voltage value U mRef :U mRef =U rated +ΔU total It needs to be raised to U, and furthermore, the output line voltage of the split-phase two-wire system is U LL =U rated *2=U m +U s Therefore, since the output line voltage of the system load 20 is kept constant, when the output voltage of the master rises, the output voltage of the slave is lowered (current energy storage power output voltage U s The corresponding target voltage value U sRef It is necessary to lower it to U sRef =U rated -ΔU total , P s =U s Base I sBased on this, the slave's output power is reduced.

[0091] As shown in Figure 10, when ΔSOC > 0, the master output voltage is U m =U mRef =U rated +ΔU total Raise the output voltage of the slave to U s =U sRef =U rated -ΔU total Reduce the master output power P m Further increasing the slave output power P s By further reducing this, SOC equalization is achieved. When ΔSOC < 0, the master output voltage is set to U m =U mRef =U rated -ΔU total Lower the slave output voltage to U s =U sRef =U rated +ΔU total Increase the master output power P m Further reducing the slave's output power P s By further increasing this, we will achieve SOC equalization.

[0092] In this case, the total target voltage adjustment value is ΔU total =(ΔSOC / 2)*U rated And here, SOC m SOC s Both ΔSOC and ΔSOC are numbers between 0 and 1, and when expressed as a percentage, for example, the master SOC m 80% is the slave SOC s The percentage is 50%, and the ΔSOC is 30%.

[0093] In this invention, ΔU totalIf the adjustment range is too large, the processing speed for equalizing the SOC of the two energy storage power supplies will be relatively large, which may affect the stability of the individual load. Therefore, in order to improve the stability of the individual load, a preferred embodiment of the present invention employs a two-stage determination calculation process using ΔSOC and the output load power of the individual unit, and further employs a variable output voltage step control method to control ΔU total To achieve adjustments to this, the specific implementation method is as follows:

[0094] (1) The master sets the current SOC difference value ΔSOC between the master and the slave. _j Therefore, the first target voltage adjustment value ΔU for the jth voltage adjustment is given by the following formula. SOC_j Calculate, ΔU SOC_j =(ΔSOC _j / 2)×U rated ×r1 Here, r1 is the proportionality constant, which generally correlates with the AC output voltage of the individual component and satisfies the voltage range for typical electrical equipment. For example, if the AC output of the individual component is 110V, then r1 takes values ​​of (10%, 20%).

[0095] (2) Since the output voltage of each energy storage power source is dynamically adjusted, output power adjustment and output voltage smoothing processing are added to prevent individual loads from experiencing power fluctuations due to the adjustment of the output voltage.

[0096] Each energy storage power source has its own AC output power P m_j Based on the change, the second target voltage adjustment value ΔU for the jth voltage adjustment is as follows: p_j Calculate.

[0097] a. By employing sliding window filtering, the average value of the AC output power cycle during the jth voltage adjustment of the master or slave P mMean_j Calculate. b. Power value P removed from the sliding window filter during the jth voltage adjustment. m_k0_j Record the (first value in the slide window). c. Power change ratio K during the jth voltage adjustment is given by the following formula. u_j Calculate. K u_j =(P m_j -P m_k0_j ) / P mMean_j d. Output power fluctuation (power change ratio K) u_j ) From this, the second target voltage adjustment value ΔU for the jth voltage adjustment is given by the following formula p_j Calculate. ΔU p_j =K u_j *ΔU SOC_j

[0098] (3) In order to achieve both the dynamic adjustment speed of the SOC and the stability of the system during voltage adjustment, the target voltage adjustment value for the jth voltage adjustment can be calculated using the following formula. ΔU _j =ΔU SOC_j *r² + ΔU p_j *r3 Here, r2 and r3 are weights, and r2 + r3 = 1. If the weight of r3 is greater (r3 > r2), the power of the individual component will be more stable, and if the weight of r2 is greater (r2 > r3), the system will adjust faster.

[0099] In one specific embodiment, the voltage adjustment step may be calculated by employing an averaging method as follows. ΔU _j =ΔU SOC_j *0.5+ΔU p_j *0.5

[0100] By obtaining the target voltage adjustment value for the jth voltage adjustment, the corresponding step target voltage value can be calculated for each voltage adjustment of the master or slave. Specifically, if ΔSOC > 0, the step target voltage value for the jth voltage adjustment for the master is U mRef_j =U rated +ΔU _j As such, the step target voltage value for the jth voltage adjustment for the slave is U sRef_j =U rated -ΔU_j Calculated as follows, if ΔSOC < 0, the step target voltage value for the jth voltage adjustment relative to the master is U mRef_j =U rated -ΔU _j As such, the step target voltage value for the jth voltage adjustment for the slave is U sRef_j =U rated +ΔU _j It is calculated as follows.

[0101] In this embodiment, the target voltage adjustment value ΔU during the jth voltage adjustment is _j is ΔU SOC_j and ΔU p_j We are considering the two factors ΔU SOC_j This is for equalizing the amount of power from each energy storage power source, and the target voltage adjustment total value ΔU total It takes a value of 10% to 20%, representing the system's need to quickly equalize power consumption, and ΔU p_j This is intended to further stabilize the power supply of each energy storage power source itself, and represents the stability of each energy storage power source.

[0102] In order for this split-phase two-wire system to achieve total energy equalization, the sum of the voltages adjusted for each energy storage power source is the target voltage adjustment total value ΔU total (If ΔSOC > 0, the master voltage is ΔU total The slave voltage increases, and ΔU total On the other hand, when ΔSOC < 0, the master voltage is ΔU total The slave voltage decreases, and ΔU total (Increase) However, in this invention, the goal is not to complete the adjustment in one step, but rather to achieve ΔU SOC_j and ΔU p_j Taking all of the above into consideration, the target voltage adjustment value each time is ΔU _j =ΔU SOC_j *r² + ΔU p_j *r3 adjusts the output voltage of the master and slave in a stepwise manner, ΔU total =ΔU _1 +ΔU _2 +ΔU _3 +...+ΔU _MFurthermore, as shown for j=1,2,3,...,M, the total energy can finally be equalized after M adjustments.

[0103] Master is target voltage value U mRef The slave is the target voltage value U sRef By adjusting it step by step so that the master output frequency P m and slave output frequency P s This enables gradual and incremental adjustment, further adjusting the battery discharge rate in the energy storage power supply, actively equalizing the State of Charge (SOC) of the two energy storage power supplies, and making the entire system more stable.

[0104] Embodiment 2 of the present invention is also preferably a three-phase four-wire system, which is a three-phase AC power supply system configured such that three independent energy storage power sources are connected in a star configuration on the AC output side, the phases of the AC outputs are shifted by 120° from each other, and a neutral wire is connected.

[0105] Specifically, as shown in Figure 11, the three-phase four-wire system comprises three energy storage power sources: a first energy storage power source 11, a second energy storage power source 12, and a third energy storage power source 13, all capable of outputting AC power in an off-grid state; a system load 20 (in this embodiment, the system load is a three-phase load); and a first individual load 31, a second individual load 32, and a third individual load 33. The first energy storage power source 11, the second energy storage power source 12, and the third energy storage power source 13 are connected by communication. The neutral wires (N) on the AC output sides of the power source 12 and the third energy storage power source 13 are connected to the common point of the neutral wires of the system load 20. The live wire (L1) of the first energy storage power source 11, the live wire (L2) of the second energy storage power source 12, and the live wire (L3) of the third energy storage power source 13 are each individually connected to the system load 20. The AC output side of the first energy storage power source 11 is connected to a single load 31, the AC output side of the second energy storage power source 12 is connected to a single load 32, and the AC output side of the third energy storage power source 13 is connected to a single load 33.

[0106] In the three-phase four-wire system, the output voltage U1 of the first energy storage power supply 11, the output voltage U2 of the second energy storage power supply 12, and the output voltage U3 of the third energy storage power supply 13 are all initially at their rated AC output voltage values ​​U rated (100Vac or 120Vac).

[0107] Furthermore, the power equalization control method for the three-phase four-wire system includes the following steps.

[0108] D1: Master and Slave Assignment The specific procedure for assigning master and slave roles involves connecting three independent energy storage power sources via communication, automatically assigning master and slave roles in a competitive manner, identifying one energy storage power source as the master, and the other two as slaves. The specific procedure for assigning master and slave roles in this three-phase four-wire system differs from a split-phase two-wire system only in that the phases of the master and slaves are shifted by 120°; the other specific procedures are the same, so no further explanation is needed here.

[0109] D2: Obtain the remaining capacity of multiple energy storage power sources, calculate the average value of the remaining capacities of the multiple energy storage power sources, then subtract the average value from the remaining capacity of each energy storage power source to find the difference value. If the difference value is greater than 0, increase the output voltage of the corresponding energy storage power source to increase its output power. If the difference value is less than 0, decrease the output voltage of the corresponding energy storage power source to reduce its output power. Repeat the above until the remaining capacities of all energy storage power sources are equal.

[0110] In this three-phase four-wire system, the master acquires the remaining capacities SOC1, SOC2, and SOC3 of each energy storage power source, and the phases of the master and slaves are shifted by 120°, so that the total output voltage of the three-phase four-wire system consisting of three independent energy storage power sources is kept constant.

[0111] The average State of Charge (SOC) of the three energy storage power sources is the SOC ave = (SOC1 + SOC2 + SOC3) / 3 is used to calculate the SOC of each current energy storage power source. i (i=1, 2, 3) and SOC ave Compare and SOC i SOC ave If it is equal to, there is no need to increase or decrease the output power, SOC i <SOC ave In this case, the output power is reduced, SOC i >SOC ave In this case, the output power is increased.

[0112] Since the total output voltage is maintained constant and the three-phase load does not change, the total current I does not change. Therefore, the present invention further increases or decreases the output power of each energy storage power supply by adjusting the voltage of each energy storage power supply. In this case, the output voltage U1 of the first energy storage power supply 11 is set to the corresponding target voltage value U 1Ref =U rated +ΔU 1total Adjust the output voltage U2 of the second energy storage power supply 12 to the corresponding target voltage value U 2Ref =U rated +ΔU 2total Adjust the output voltage U3 of the third energy storage power supply 13 to the corresponding target voltage value U 3Ref =U rated +ΔU 3total Adjust to this, and here, ΔU 1total +ΔU 2total +ΔU 3total =0. Target voltage adjustment total value ΔU itotal If (i=1, 2, 3) is 0, the remaining capacity (SOC) of the corresponding energy storage power source. i =SOC ave This indicates that there is no need to increase or decrease the output power, ΔU itotal If negative, the SOC of the corresponding energy storage power source. i <SOC ave This indicates that the output power needs to be reduced, ΔU itotal If positive, the SOC of the corresponding energy storage power source. i >SOC ave This indicates that the output power needs to be increased.

[0113] In this case, the formula for calculating the total target voltage adjustment value is ΔU itotal =(SOC i -SOC ave )×U rated And i = 1, 2, 3, U rated This is the rated voltage of the energy storage power supply. Here, SOC i SOC aveThese are all numbers between 0 and 1, and when expressed as percentages, for example, the remaining capacity SOC1 of the first energy storage power source 11 is 80%, the remaining capacity SOC2 of the second energy storage power source 12 is 50%, and the remaining capacity SOC3 of the third energy storage power source 13 is 30%. ave That is 53.3%.

[0114] In this invention, ΔU itotal If the adjustment range is too large, the SOC equalization processing speed of each energy storage power supply will be relatively large, which may affect the stability of individual loads. Therefore, in order to improve the stability of individual loads, Embodiment 2 of the present invention employs a variable output voltage step control method, which is achieved by a two-stage determination calculation process using the SOC difference value and the output load power of the individual loads, thereby reducing ΔU itotal To achieve adjustments to this, the specific implementation method is as follows:

[0115] (1) The energy storage power supply for each unit is determined by the following formula, which sets the first target voltage adjustment value ΔU for the jth voltage adjustment. SOC_i_j Calculate, ΔU SOC_i_j =(SOC i_j -SOC ave )×U rated ×r1 i Here, r1 i r1 is a proportionality constant, which generally correlates with the AC output voltage of a single unit and is a number that satisfies the voltage range for typical electrical equipment. For example, if the AC output of a single unit is 110V, then r1 i It takes values ​​of (10%, 20%).

[0116] (2) Since the output voltage of each energy storage power source is dynamically adjusted, output power adjustment and output voltage smoothing processing are added to prevent individual loads from experiencing individual load power fluctuations due to the adjustment of the output voltage.

[0117] Each energy storage power source has its own AC output power P m_i_j Based on the changes in the voltage, the second target voltage adjustment value ΔU for each jth voltage adjustment is determined as follows:p_i_j Calculate.

[0118] a. By employing sliding window filtering, the average value of the AC output power cycle during the jth voltage adjustment of each energy storage power supply P mMean_i_j Calculate. b. Power value P removed from the sliding window filter during the jth voltage adjustment. m_k0_i_j Record the (first value in the slide window). c. The power change ratio K during the jth voltage adjustment is given by the following formula. u_i_j Calculate. K u_i_j =(P m_i_j -P m_k0_i_j ) / P mMean_i_j d. Output power fluctuation (power change ratio K) u_i_j ) From this, the second target voltage adjustment value ΔU for the jth voltage adjustment of each energy storage power supply is calculated using the following formula. p_i_j Calculate. ΔU p_i_j =K u_i_j *ΔU SOC_i_j

[0119] (3) In order to achieve both the dynamic adjustment speed of the SOC and the stability of the system during voltage adjustment, the target voltage adjustment value for the jth voltage adjustment for the i-th energy storage device can be calculated using the following formula. ΔU i_j =ΔU SOC_i_j *r2 i +ΔU p_i_j *r3 i Here, r2 i and r3 i is the weight, and r2 i +r3 i = 1. r3 i The weight of (r3) is greater. i >r2 i ) If so, the power of the individual unit will be more stable, r2 i The weight of (r2) is greater ( i >r3 i ) If so, the system adjustment speed will be faster.

[0120] By obtaining the target voltage adjustment value for the jth voltage adjustment for the i-th energy storage device, it is possible to calculate the corresponding step target voltage value for each voltage adjustment of the energy storage power supply. Specifically, SOC i_j (Remaining capacity of the i-th energy storage device at the j-th voltage adjustment) > SOC ave In this case, the step target voltage value for the jth voltage adjustment for the i-th energy storage device is U iRef_j =U rated +ΔU i_j Calculated as SOC i_j (Remaining capacity of the i-th energy storage device at the j-th voltage adjustment) <SOC ave In this case, the step target voltage value for the i-th energy storage power supply during the j-th voltage adjustment is U iRef_j =U rated -ΔU i_j It is calculated as follows.

[0121] In this embodiment, the target voltage adjustment value ΔU for the jth voltage adjustment of the i-th energy storage device. i_j is ΔU SOC_i_j and ΔU p_i_j We are considering the two factors ΔU SOC_i_j This is for equalizing the amount of power from each energy storage power source, and the target voltage adjustment total value ΔU itotal It takes a value of 10% to 20%, representing the system's need to quickly equalize power consumption, and ΔU p_i_j This is intended to further stabilize the power supply of each energy storage power source itself, and represents the stability of each energy storage power source.

[0122] In order for this three-phase four-wire system to achieve equalization of total power, the sum of the voltages adjusted for each energy storage power source is the target voltage adjustment total value ΔU itotal (i=1, 2, 3, meaning the i-th energy storage power source in the system) However, in this invention, the adjustment is not completed in one step, but ΔU SOC_i_j and ΔU p_i_jTaking everything into consideration, the target voltage adjustment value ΔU for each time _i_j =ΔU SOC_i_j *r2 + ΔU p_i_j *r3, and the output voltages of the master and slave are adjusted step by step and gradually. ΔU itotal =ΔU _i_1 +ΔU _i_2 +ΔU _i_3 +... + ΔU _i_M And as shown by j = 1, 2, 3,..., M, after M adjustments, the equalization of the total power consumption can be finally achieved.

[0123] By gradually adjusting each energy storage power supply so that it reaches the target voltage value U iRef , the step - by - step and gradual adjustment of the output frequency P m_i of each energy storage power supply is realized. Furthermore, the adjustment of the discharge rate of the battery in the energy storage power supply is realized, the SOC of each energy storage power supply is actively equalized, and the whole system is made more stable.

[0124] According to the power quantity equalization control method proposed in Embodiment 2 of the present invention, the above single-phase two-wire system and three-phase four-wire system control to keep the output line voltage constant, thereby providing stable power support to the load. At the same time, in real time, according to the remaining capacity SOC of each energy storage power supply and the load power situation, the output voltage of a single energy storage power supply is adjusted to gradually increase the loaded output power of the energy storage power supply with a high power quantity, while gradually reducing the loaded output power of the energy storage power supply with a low power quantity. Thus, the active power quantity equalization control of the single-phase two-wire system and the three-phase four-wire system is realized, effectively solving the problem of shortening the loaded continuous operation time of the system caused by the inconsistency of the remaining capacity SOC. At the same time, considering the stability of each single load every time the output voltage is adjusted, and by adjusting the output voltage of each energy storage device step by step and gradually by means of a cyclic adjustment method, the fluctuation of the single load power is prevented, and the single load operates and is used normally under the rated voltage and within a certain voltage change range, further stabilizing the system. Avoiding the inconsistency of the power consumption of each energy storage power supply constituting the system and making the battery continuous operation time of each energy storage power supply the same, while ensuring that all kinds of electrical equipment can operate and be used normally under the rated voltage and within a certain voltage change range, and avoiding the operation of each single load under the conditions of too high or too low voltage, greatly extending the life of the electrical equipment, reducing energy consumption, minimizing the possibility of damage to the electrical equipment, and ensuring electrical safety.

[0125] The background part of the present invention can include background information related to the problems and environment of the present invention, rather than others describing the prior art. Therefore, the content included in the background art part does not indicate the applicant's approval of the prior art.

[0126] The above description further elaborates on the present invention with reference to specific / preferred embodiments, and it is not considered that the specific implementation of the present invention is limited to these descriptions alone. Those skilled in the art in which the present invention pertains may make several substitutions or modifications to the above-described embodiments without departing from the spirit of the invention, and all such substituted or modified embodiments should be considered to fall within the scope of protection of the present invention. In this specification, descriptions made by reference to terms such as “certain embodiment,” “several embodiments,” “preferred embodiment,” “example,” “specific example,” or “several examples” mean that the specific features, structures, materials, or characteristics described by this embodiment or example are included in at least one embodiment or example of the present invention. In this specification, exemplary expressions of the above terms do not necessarily apply to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in an appropriate manner in one or more embodiments or examples. Notwithstanding, those skilled in the art may combine or link different embodiments or examples, or features of different embodiments or examples, as long as they do not contradict each other. While embodiments and advantages of the present invention have been described in detail above, it should be understood that various modifications, substitutions, and changes are possible within this specification without departing from the scope defined by the appended claims.

Claims

1. A method for controlling the equalization of power output in a multiphase AC system consisting of an energy storage device, S1: A step of obtaining the remaining capacity of multiple energy storage devices, S2: A step of calculating the average value of the remaining capacity of the plurality of energy storage devices, A method for controlling the equalization of power consumption in a multiphase AC system comprising energy storage devices, characterized by the following steps: S3: Subtracting the average value calculated in step S2 from the remaining capacity of each of the energy storage devices to obtain a difference value; if the difference value is greater than 0, increasing the output voltage of the corresponding energy storage device to increase the output power of the energy storage device; and if the difference value is less than 0, decreasing the output voltage of the corresponding energy storage device to reduce the output power of the energy storage device.

2. Step S3 specifically means, The remaining capacity SOC of the i-th energy storage device ｉ Therefore, the average SOC calculated in step S2 ａｖｅ The difference value is obtained by subtracting the value, and the corresponding output voltage on the energy storage device side is set to the target voltage value U ｉＲｅｆ This includes adjusting the output power of the energy storage device by adjusting the target voltage value to U ｉＲｅｆ = U ｒａｔｅｄ +ΔU ｉ U ｒａｔｅｄ ΔU is the rated voltage of the energy storage device, ｉ The power equalization control method according to claim 1, wherein i is a target voltage adjustment value calculated based on the difference value, i = 1 to n, and n is the number of energy storage devices.

3. The formula for calculating the target voltage adjustment value is: ΔU ｉ = (SOC ｉ - SOC ａｖｅ ) × U ｒａｔｅｄ The method for controlling power quantity equalization according to claim 2, characterized in that it is as described above.

4. The power equalization control method according to claim 1, further comprising the step of repeating steps S1 to S3 after step S3 until the remaining capacities of each of the energy storage devices are all equal.

5. Step S3 specifically means, The remaining capacity SOC of the i-th energy storage device ｉ＿ｊ Therefore, the average SOC calculated in step S2 ａｖｅ The difference value is obtained by subtracting the value, and the corresponding output voltage on the energy storage device side is set to the step target voltage value U ｉＲｅｆ＿ｊ This includes adjusting the output power of the energy storage device by adjusting the step target voltage value U ｉＲｅｆ＿ｊ = U ｒａｔｅｄ +ΔU ｉ＿ｊ U ｒａｔｅｄ ΔU is the rated voltage of the energy storage device, ｉ＿ｊ The power equalization control method according to claim 4, wherein is a target voltage adjustment value for the jth voltage adjustment for the i-th energy storage device calculated based on the difference value, i = 1 to n, n is the number of energy storage devices, and j is the current number of voltage adjustments.

6. The formula for calculating the target voltage adjustment value for the jth voltage adjustment for the i-th energy storage device is: ΔU ｉ＿ｊ =ΔU ＳＯＣ＿ｉ＿ｊ *r2 ｉ +ΔU ｐ＿ｉ＿ｊ *r3 ｉ And, Here, ΔU ＳＯＣ＿ｉ＿ｊ This is the first target voltage adjustment value for the jth voltage adjustment of the i-th energy storage device, calculated based on the difference value, and ΔU ｐ＿ｉ＿ｊ r2 is a second target voltage adjustment value for the jth voltage adjustment of the i-th energy storage device, calculated based on the change in the AC-side output power of the i-th energy storage device, and r2 ｉ and r3 ｉ is the weight, and r² ｉ +r3 ｉ The power equalization control method according to claim 5, characterized in that = 1.

7. The formula for calculating the first target voltage adjustment value for the i-th energy storage device during the j-th voltage adjustment is ΔU ＳＯＣ＿ｉ＿ｊ = (SOC ｉ＿ｊ - SOC ａｖｅ ) × U ｒａｔｅｄ ×r1 ｉ And r1 ｉ The power equalization control method according to claim 6, characterized in that is a proportionality constant.

8. r1 ｉ The power equalization control method according to claim 7, characterized in that the value takes a value of 10% to 20%.

9. The formula for calculating the second target voltage adjustment value for the i-th energy storage device during the j-th voltage adjustment is ΔU ｐ＿ｉ＿ｊ = K ｕ＿ｉ＿ｊ *ΔU ＳＯＣ＿ｉ＿ｊ And here, K ｕ＿ｉ＿ｊ is the power change ratio during the jth voltage adjustment for the i-th energy storage device, and K ｕ＿ｉ＿ｊ = (P ｍ＿ｉ＿ｊ -P ｍ＿ｋ０＿ｉ＿ｊ ) / P ｍＭｅａｎ＿ｉ＿ｊ And in the formula, P ｍ＿ｉ＿ｊ This is the AC output power during the jth voltage adjustment for the i-th energy storage device, and P ｍＭｅａｎ＿ｉ＿ｊ P is the periodic average value of the AC side output power during the jth voltage adjustment for the i-th energy storage device, calculated using sliding window filtering, and P ｍ＿ｋ０＿ｉ＿ｊ The power equalization control method according to claim 6, characterized in that is the power value removed from the sliding window filter during the jth voltage adjustment for the i-th energy storage device.

10. A multiphase AC system comprising energy storage devices, comprising a plurality of energy storage devices and a system load, wherein the plurality of energy storage devices are communicated with one another, the live lines on the AC output side of the plurality of energy storage devices are each connected to the system load, the neutral lines of the plurality of energy storage devices are connected to a common point of the neutral lines of the system load, and power equalization control is performed on the plurality of energy storage devices by employing the power equalization control method described in any one of claims 1 to 9.

11. A multiphase AC system comprising an energy storage device according to claim 10, further comprising at least one standalone load, wherein the standalone load is independently connected to the AC output side of at least one of the plurality of energy storage devices.

12. Before step S1, A multiphase AC system comprising an energy storage device according to claim 10, further comprising the step of communicating and connecting a plurality of energy storage devices, and assigning master and slave roles such that one of the plurality of energy storage devices is identified as the master and the other energy storage devices are identified as slaves.

13. The previous master was The power supply frequency phase signal is transmitted to the slave at the point of zero crossing in the power supply frequency cycle of the master. To obtain the remaining capacity of the aforementioned multiple energy storage devices, A multiphase AC system comprising an energy storage device according to claim 12, characterized in that it is used to acquire a target voltage value for each of the energy storage devices and transmit it to a corresponding slave by the power equalization control method according to any one of claims 2, 3, or 5 to 9.

14. The aforementioned slave is A multiphase AC system comprising an energy storage device according to claim 12, characterized in that it is used to acquire and track a power frequency phase signal transmitted from the master, and to control the power frequency phase of the slave so as to lag behind the power frequency phase of the master.

15. The multiphase AC system comprising the energy storage devices according to claim 14, characterized in that there are two of the energy storage devices, the multiphase AC system comprising the energy storage devices is a split-phase two-wire system, and the power supply frequency phase of the slave lags the power supply frequency phase of the master by 180°.

16. The multiphase AC system comprising energy storage devices according to claim 14, characterized in that the number of energy storage devices is three, the multiphase AC system comprising the energy storage devices is a three-phase four-wire system, the number of slaves is two, and the power supply frequency phases between the three energy storage devices are shifted by 120° each.

17. A storage medium characterized by storing a computer program that is executed by a processor and configured to perform the power equalization control method described in any one of claims 1 to 9.

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