CN103023085B - Independent photovoltaic storage battery grouping management method - Google Patents

Abstract

The invention discloses a group management method for independent photovoltaic storage batteries, which belongs to the technical field of new energy power generation control. The main components of the stand-alone photovoltaic accumulator system involved in the present invention include photovoltaic cells, accumulators, power converters, loads and the like. The group management method of independent photovoltaic batteries is to concentrate the limited photovoltaic power for a period of time to charge a battery group, and to discharge as little as possible before it is not fully charged, so that it can quickly reach the full charge state, and implement this strategy for different groups in a cycle. The invention is applicable to the situation of continuous shortage of photovoltaic electric energy, so that each storage battery group can be released from the state of long-term undercharging, avoiding its cyclic use in a low charge state, and prolonging the service life of the storage battery.

Description

Independent photovoltaic battery group management method

technical field

The invention relates to a group management method for independent photovoltaic storage batteries, which belongs to the technical field of new energy power generation control.

Background technique

Solar energy has random and intermittent characteristics. To achieve continuous and stable power supply for a stand-alone photovoltaic power generation system, necessary energy storage equipment is required. Batteries have the characteristics of low cost, convenient maintenance, and high charging and discharging efficiency, which make them a common energy storage method for photovoltaic power generation systems.

At the same time, the charging and discharging of batteries used in photovoltaic power generation systems has some new features. When the battery is fully charged mainly depends on the environmental conditions (light intensity, ambient temperature, whether there is an object to block, etc.) After the battery is over-discharged, it is also difficult to recharge it in a short period of time, so that the battery is in a low state of charge (SOC) for a long time, and it is cycled at a low SOC.

Therefore, the storage battery has become the most vulnerable part of the photovoltaic system. Improper storage battery management methods will cause it to fail prematurely, resulting in an increase in system replacement costs and a decrease in system reliability.

Contents of the invention

The purpose of the present invention is to provide a group management method for independent photovoltaic storage batteries, which can maximize the use of existing photovoltaic power, charge the storage batteries as much and as quickly as possible, and get rid of the long-term low charge state Cycle use under low charge state, thus prolonging the service life of the battery.

The purpose of the present invention is achieved through the following technical solutions:

A method for group management of independent photovoltaic storage batteries, comprising the following steps;

First detect the terminal voltage V _Bat and the maximum allowable charging current I _Bat of each battery pack, and determine the state of charge SOC of each battery pack according to them;

Define a charging and discharging sequence vector C(1,...,N) of the battery pack, arrange C(1)~C(N) from low to high according to the state of charge SOC of the battery pack, C(1) the battery pack is in priority charging and The final discharge state is Z1, the C(N) battery pack is in the priority discharge and the final charge state is Z2;

The steps to manage battery charging include:

1) Detect the photovoltaic array output power PV(t) and load power Load(t), and calculate the remaining photovoltaic power O(t), said O(t)=PV(t)-Load(t);

2) Count the number L of battery packs whose state of charge SOC is lower than 100%;

And according to the terminal voltage V _Bat of each battery pack and the maximum allowable charging current I _Bat , it is determined that O(t) can meet the charging requirements of several battery packs. The method for checking the number M of battery packs that can be charged is:

$\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; orO</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&DoubleRightArrow;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

When formula (1) is established, that is, all batteries are fully charged (L=0) or O(t)≤0, then M=0, stop charging;

$<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; and\; O</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&DoubleRightArrow;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

When formula (2) is established, O(t) is fully charged into battery pack C(1);

$<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; and</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; and\; O</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&DoubleRightArrow;</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

When formula (3) is established, after the M-1 battery packs before the vector C are charged with their maximum allowable charging current, all the remaining photovoltaic power is charged into the battery pack C(M);

$<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; L</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; and\; O</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&DoubleRightArrow;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

When formula (4) is established, the M battery packs before the vector C are all charged with their maximum allowable charging current; after the battery packs are charged, update their SOC values;

3) If any storage battery group is fully charged, put this group at the end of the vector C, and the other groups move forward in sequence;

4) Otherwise, return to the calculation of O(t) and the approved number of rechargeable battery packs M, and start a new cycle;

The steps to manage battery discharge include:

1) Discharge from the C(N) battery pack first;

2) When its state of charge SOC drops below 60%, update the C vector from low to high according to the state of charge SOC of the battery pack other than C(1), so that the battery pack C(1) is always in the Z1 state, and C( N) The battery pack is in the state of Z2;

3) When the SOC of all C(N) battery packs is lower than or equal to 60%, the battery packs are discharged sequentially in the order of C(N), C(N-1),...,C(1); The discharge priority of the battery pack is the lowest. Only when the state of charge SOC of other banks has dropped to 30% of the lowest state of charge, the battery pack in the Z1 state will start until its state of charge SOC also reaches the lowest state of charge. Then stop the battery discharge.

Compared with the prior art, the beneficial effect of the present invention is: using this charging and discharging strategy, when the remaining photovoltaic power O(t) is not much, it can be concentrated for charging C(1), so that it can reach a full charge state quickly and get rid of It is in a state of low charge for a long time; when there is a lot of photovoltaic power, after meeting the charging demand of C(1), it can also charge other battery packs at the same time, making full use of the existing photovoltaic power. When discharging, the battery pack in the Z1 state should be discharged as little as possible before it is fully charged, so as to reach the fully charged state as soon as possible, and avoid its cycle use under low SOC.

Description of drawings

Figure 1 is a structural diagram of a stand-alone photovoltaic battery system;

Fig. 2 is a flow chart of a method for group management of charging of independent photovoltaic batteries;

Fig. 3 is a flow chart of a method for group management of discharge of independent photovoltaic storage batteries.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

The principle of battery grouping is: after determining the total battery capacity according to the photovoltaic cell capacity and load demand, the batteries are grouped based on the discharge rate recommended by the manufacturer to control the discharge current of a single battery group to the load, so that each battery group is based on its rated capacity. When the current is discharged, it can meet the load demand alone. In this embodiment, the storage battery is divided into three groups, and when each battery group is discharged at its rated current, it can individually meet the load demand.

Fig. 1 is a structural diagram of a stand-alone photovoltaic storage battery system of the present invention. This system adopts the DC bus structure, and the bus voltage V _DB is stable at 220V. After the photovoltaic array passes the maximum power point tracking (MPPT), the power is sent to the DC bus through a boost converter, and its output voltage is stabilized at 220V. Each storage battery pack is connected to the DC bus through a separate bidirectional DC/DC, so that the step-down control from the DC bus to each battery pack terminal and the boost control from each storage battery pack terminal to the DC bus can be realized. The photovoltaic battery management center estimates the SOC of each battery group based on the terminal voltage and current of each battery group, and controls the on-off of the bidirectional DC/DC connected to each battery group accordingly.

Define a battery pack charging and discharging sequence vector C(1,...,N), arrange C(2)～C(N) from low to high according to the state of charge SOC of the battery pack except C(1), C(1) The battery pack is in the priority charging and final discharging state Z1, and the C(N) battery pack is in the priority discharging and final charging state Z2. For example, C=(2, 1, 3) indicates that the battery pack numbered 2 has the highest charging priority and the lowest discharging priority, and the battery pack numbered 3 has the lowest charging priority and the highest discharging priority.

Fig. 2 is a flow chart of a group management method for charging of independent photovoltaic storage batteries. When charging, first detect and judge the terminal voltage V _Bat and the maximum allowable charging current I _Bat of each battery pack, and estimate the state of charge SOC of each battery pack according to them, take out the battery pack in the Z1 state from the storage unit, and assign it to C( 1), in addition to C(1), arrange C(2)~C(N) according to the SOC of the battery group from low to high; then detect the photovoltaic array output power PV(t) and load power Load(t), Calculate the remaining photovoltaic power O(t), count the number L of battery packs with SOC<100%, and determine how many battery packs O(t) can satisfy according to the terminal voltage V _Bat of each battery pack and the maximum allowable charging current I _Bat Charging demand, the number M of battery packs that can be charged is approved. If all the batteries are fully charged or O(t)<=0, then M=0, stop charging, otherwise, charge the battery packs in the M group before C, and update the SOC. If any accumulator group is fully charged, put it at the end of C, and move the other groups forward in sequence (for example, M=2, according to C=(2,1,3), charge the second group and the first group of accumulators at the same time, If the second group is full, then C is updated to C=(1, 3, 2)), otherwise return to calculate O(t) and check M, and start a new cycle. Here, it is not necessarily the battery pack C ( 1) Full charge first, when the photovoltaic power is sufficient, the SOC of battery pack C(1) is low and the SOC of battery pack C(2) is high, then battery pack C(2) may be fully charged first. Using this charging strategy, when the remaining photovoltaic power O(t) is not much, C(1) can be charged intensively, so that it can reach a full charge state quickly and get rid of the long-term low charge state; After meeting the charging requirements of C(1), it can also charge other battery packs at the same time, making full use of the existing photovoltaic power.

Fig. 3 is a flow chart of a method for group management of discharge of independent photovoltaic storage batteries. In order to avoid frequent switching between battery packs due to similar state of charge SOC during the discharge process, two switching points (SOC=60% and SOC=30%) are set. When discharging, first detect the terminal voltage V _Bat and current I _Bat of each battery pack, and estimate the state of charge SOC of each battery pack according to them, take out the battery pack in the Z1 state from the storage unit, and assign it to C(1), except In addition to C(1), arrange C(2)～C(N) from low to high according to the state of charge SOC of the battery group; discharge from group C(N) first, and when the SOC of the battery group drops to 60%, follow the steps except The state of charge SOC of the battery pack other than C(1) updates the C vector from low to high, so that the battery pack C(1) is always in the Z1 state, and the C(N) battery pack is in the Z2 state; when the C(N) battery pack When the SOC is lower than or equal to 60%, the batteries are discharged in the order of C(N), C(N-1),...,C(1). The battery pack in the Z1 state has the lowest discharge priority. Only when the state of charge SOC of other banks has dropped to 30% of the lowest state of charge, the battery pack in the Z1 state will start until its state of charge SOC also reaches the lowest state. When the state of charge is reached, the battery discharge is stopped. In this way, the battery pack in the Z1 state can be discharged as little as possible before it is fully charged, so as to reach the fully charged state as soon as possible, and avoid its cycle use under low SOC.

In addition to the above-mentioned embodiments, the present invention can also have other implementations, and all technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims (1)

1. A method for group management of independent photovoltaic storage batteries, characterized in that, comprising the following steps: The principle of battery grouping is to determine the total battery capacity according to the photovoltaic cell capacity and load demand, and control the discharge current of a single battery group to the load at the discharge rate recommended by the manufacturer to group the batteries. When discharging, it can meet the load demand alone; Detect the terminal voltage V _Bat and the maximum allowable charging current I _Bat of each battery pack, and determine the state of charge SOC of each battery pack according to them; Define a charging and discharging sequence vector C(1,...,N) of the battery pack, arrange C(1)~C(N) from low to high according to the state of charge SOC of the battery pack, C(1) the battery pack is in priority charging and The final discharge state is Z1, the C(N) battery pack is in the priority discharge and the final charge state is Z2; The steps to manage battery charging include: 1) Detect photovoltaic array output power PV(t) and load power Load(t), calculate remaining photovoltaic power O(t), said O(t)=PV(t)-Load(t); 2) Count the number L of storage battery packs whose state of charge SOC is lower than 100%; And according to the terminal voltage V _Bat of each battery pack and the maximum allowable charging current I _Bat , it is determined that O(t) can meet the charging requirements of several battery packs. The method for checking the number M of battery packs that can be charged is: $\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; or\; O</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&DoubleRightArrow;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ When formula (1) is established, that is, all batteries are fully charged (L=0) or O(t)≤0, then M=0, stop charging; $<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; and\; O</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&DoubleRightArrow;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$ When formula (2) is established, O(t) is fully charged into battery pack C(1); $<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; and</span>}<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; <</span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; and\; O</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&DoubleRightArrow;</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&le;</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$ When formula (3) is established, after the M-1 battery packs before the vector C are charged with their maximum allowable charging current, all the remaining photovoltaic power is charged into the battery pack C(M); $<span\; class="notranslate">\; [</span>\mathrm{<span\; class="notranslate">\; o</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>{\mathrm{<span\; class="notranslate">\; I</span>}}_{\mathrm{<span\; class="notranslate">\; bat</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; C</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; ]</span><span\; class="notranslate">\; \&Greater\; Equal;</span>\mathrm{<span\; class="notranslate">\; 0</span>}\mathrm{<span\; class="notranslate">\; and\; O</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; ></span>\mathrm{<span\; class="notranslate">\; 0</span>}<span\; class="notranslate">\; \&DoubleRightArrow;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; L</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$ When formula (4) is established, the M battery packs before the vector C are all charged with their maximum allowable charging current; after the battery packs are charged, update their SOC values; 3) If any storage battery group is fully charged, put this group at the end of the vector C, and the other groups move forward in sequence; 4) Otherwise, return to the calculation of O(t) and the approved number of rechargeable battery packs M, and start a new cycle; The steps to manage battery discharge include: 1) Discharge from the C(N) battery pack first; 2) When its state of charge SOC drops below 60%, update the C vector from low to high according to the state of charge SOC of the battery pack except C(1), so that the battery pack C(1) is always in the Z1 state, and C( N) The battery pack is in the state of Z2; 3) When the SOC of all C(N) battery packs is lower than or equal to 60%, the battery packs are discharged sequentially in the order of C(N), C(N-1),...,C(1); The discharge priority of the storage battery pack is the lowest. Only when the state of charge SOC of other groups has dropped to 30% of the lowest state of charge, the battery pack in the Z1 state will start until its state of charge SOC also reaches the lowest state of charge. Then stop the battery discharge.