Battery charging and discharging management method and battery charging and discharging management system based on inverter

Abstract

The invention relates to the technical field of inverters, in particular to a battery charging and discharging management method and a battery charging and discharging management system based on an inverter. The method comprises the following steps: acquiring a battery type and corresponding battery charging and discharging parameters; judging whether the battery has a battery management system; if yes, judging whether the inverter is successfully communicated with a battery management system of the battery or not; if the inverter successfully communicates with the battery management system of the battery, starting a first charging and discharging strategy based on the battery type and the battery charging and discharging parameters; and if the battery does not have the battery management system or the inverter does not successfully communicate with the battery management system of the battery, starting a second charging and discharging strategy based on the battery type and the battery charging and discharging parameters. According to the invention, the robustness of the inverter to the battery can be improved, the charging and discharging management of different types of batteries is safer, more accurate and more efficient, various problems caused by an unreasonable battery charging and discharging control management strategy are greatly reduced, the use efficiency of the battery is improved, and the cycle service life of the battery is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of inverters, and in particular to an inverter-based battery charge and discharge management method and a battery charge and discharge management system. Background Art

[0002] With the rapid development of photovoltaic new energy and the orientation of green energy, the demand for photovoltaic inverters is increasing significantly year by year, especially inverters with integrated inverter control and energy storage.

[0003] Inverters that integrate reverse control and energy storage usually need to be used with batteries. Their function is not only to store energy, but also to form the basis for users to realize peak and valley electricity price benefits, prevent the waste of excess photovoltaic energy, and more importantly, serve as an emergency power source during power outages.

[0004] In the related art, the inverter and the battery used with it are not necessarily from the same manufacturer. Usually, each inverter is used in combination with different types of batteries. The inverter is used with different batteries, such as lithium batteries, lead-acid batteries, etc. Due to the differences in the charging and discharging strategies of different types of batteries, the inverter and battery may not work properly, or even be damaged. Therefore, the existing inverter has poor robustness to batteries and cannot be used for charging and discharging of multiple types of batteries, resulting in low battery utilization efficiency. Summary of the invention

[0005] The technical problem to be solved by the embodiments of the present invention is to provide a battery charge and discharge management method and a battery charge and discharge management system based on an inverter, so as to solve the problem in the prior art that the inverter has poor robustness to the battery and cannot be applied to various types of batteries for charge and discharge, resulting in low battery utilization efficiency.

[0006] The present invention discloses a battery charge and discharge management method based on an inverter, which is applied to the inverter. The inverter can be connected to a battery. The battery charge and discharge management method includes:

[0007] Get the battery type and corresponding battery charge and discharge parameters;

[0008] Determine whether the battery has a battery management system;

[0009] If so, determine whether the inverter successfully communicates with the battery management system of the battery;

[0010] If the inverter successfully communicates with the battery management system of the battery, a first charge and discharge strategy is enabled based on the battery type and the battery charge and discharge parameters;

[0011] If the battery does not have a battery management system or the inverter fails to communicate successfully with the battery management system of the battery, a second charge and discharge strategy is enabled based on the battery type and the battery charge and discharge parameters.

[0012] Optionally, the first charge-discharge strategy includes a first charging strategy, and the first charging strategy includes the following steps:

[0013] Control constant current charging of the battery;

[0014] According to the battery capacity and the battery voltage and battery current transmitted in real time by the battery management system, the constant current charging is controlled to be converted into constant voltage charging or charging is stopped.

[0015] Optionally, the method of controlling the constant current charging to be converted into constant voltage charging or stopping charging according to the battery capacity and the battery voltage and battery current transmitted in real time by the battery management system specifically includes the following steps:

[0016] Determine whether the battery capacity is greater than the stop charging capacity point;

[0017] If the battery capacity is greater than the stop charging capacity point, charging is complete;

[0018] If the battery capacity is not greater than the stop charging capacity point, determine whether the battery voltage is less than the constant voltage charging voltage point;

[0019] If the battery voltage is lower than the constant voltage charging voltage point, the battery will continue to be charged with a constant current;

[0020] If the battery voltage is not less than the constant voltage charging voltage point, the control performs constant voltage charging on the battery. Under the constant voltage charging mode, it is determined whether the battery current is less than the stop charging current point;

[0021] If the battery current is less than the stop charging current point, charging is complete;

[0022] If the battery current is not less than the stop charging current point, the battery will continue to be controlled to be charged at a constant voltage.

[0023] Optionally, the second charge-discharge strategy includes a second charging strategy, and the second charging strategy includes the following steps:

[0024] Control constant current charging of the battery;

[0025] The constant current charging is converted into constant voltage charging according to the sampled battery voltage and battery type;

[0026] In the constant voltage charging mode, the battery is charged according to the battery type and the battery voltage and battery current obtained by sampling.

[0027] Optionally, the charging is performed according to the battery type and the battery current obtained by sampling, and specifically includes the following steps:

[0028] Determine whether equalization charging needs to be enabled based on the battery type;

[0029] If necessary, the battery is controlled to be charged evenly; if not, the battery is controlled to be charged more vigorously;

[0030] Determine whether the battery current is less than the stop charging current point;

[0031] If the battery current is less than the stop charging current point, the control performs float charging on the battery.

[0032] Optionally, after controlling the battery to be float charged, the following steps are further included:

[0033] Determine whether the sampled battery voltage is less than the floating charge voltage point, and determine whether the floating charge time is greater than the floating charge delay time;

[0034] If the battery voltage is greater than the floating charge voltage point, determine whether the sampled battery current is less than the stop charging current point;

[0035] If the battery current is less than the stop charging current point and the floating charge time is greater than the floating charge delay time, the charging is completed.

[0036] Optionally, the first charge and discharge strategy further includes a first discharge strategy, and the first discharge strategy includes the following steps:

[0037] Determine whether the battery capacity is lower than the stop discharge capacity point;

[0038] If the battery power is lower than the stop discharge capacity point, the battery is controlled to stop discharging;

[0039] When the inverter is not in the mains priority mode and not in the PV pre-mode, if the battery capacity is not less than the stop discharge capacity point, it is determined whether the battery capacity is less than the mains switching capacity point and whether the mains is connected, and whether the battery capacity is greater than the battery switching capacity point and whether it is in the mains bypass state;

[0040] If the battery capacity is lower than the AC power switching capacity point and the AC power is connected, the battery will be controlled to stop discharging and the AC power bypass will be switched to carry the load;

[0041] If the battery capacity is higher than the battery switching capacity point and is in the AC bypass state, the battery is controlled to resume discharge and the battery inverter is switched to carry the load.

[0042] Optionally, the second charge and discharge strategy includes a second discharge strategy, and the second discharge strategy includes the following steps:

[0043] When the inverter is not in the mains priority mode and not in the photovoltaic pre-mode, determine whether the sampled battery voltage is lower than the mains switching voltage point and whether the mains is connected, and determine whether the battery voltage is higher than the battery switching voltage point and whether it is in the mains bypass state;

[0044] If the battery voltage is lower than the AC power switching voltage point and the AC power is connected, the battery will be controlled to stop discharging and the AC power bypass will be switched to carry the load;

[0045] If the battery voltage is higher than the battery switching voltage point and is in the AC bypass state, the battery is controlled to resume discharge and the battery inverter is switched to carry the load.

[0046] Optionally, before determining whether the battery has a battery management system, the method further includes the following steps:

[0047] When the inverter is not in the mains priority mode and not in the photovoltaic pre-mode, it is determined whether the sampled battery voltage is lower than the over-discharge limit voltage point;

[0048] If the battery voltage is not lower than the over-discharge limit voltage point, determine whether the battery voltage is lower than the over-discharge limit voltage point and lasts for the over-discharge delay time;

[0049] If the battery voltage is lower than the over-discharge limit voltage point and continues for the over-discharge delay time, or the battery voltage is lower than the over-discharge limit voltage point, it is determined whether the AC power is connected. If the AC power is connected, the battery is controlled not to discharge, and the AC power bypass is loaded. If the AC power is not connected, the battery is controlled not to discharge.

[0050] The present invention also discloses a battery charge and discharge management system, which applies the above-mentioned battery discharge management method to realize battery charge and discharge management. The battery charge and discharge management system includes the following modules:

[0051] An acquisition module is used to obtain the battery type and the corresponding battery charging and discharging parameters;

[0052] A judgment module is used to determine whether the battery has a battery management system and whether the inverter successfully communicates with the battery management system of the battery;

[0053] A first enabling module, configured to enable a first charge and discharge strategy based on the battery type and the battery charge and discharge parameters if the inverter successfully communicates with the battery management system of the battery;

[0054] The second enabling module is used to enable a second charging and discharging strategy based on the battery type and the battery charging and discharging parameters if the battery has no battery management system or the inverter fails to communicate successfully with the battery management system of the battery.

[0055] Compared with the prior art, the beneficial effect of the inverter-based battery charge and discharge management method provided by the embodiment of the present invention is that: the battery charge and discharge management method obtains the battery type and the corresponding battery charge and discharge parameters, and determines whether the battery has a battery management system and whether the inverter and the battery management system of the battery successfully communicate when the battery has a battery management system. When the inverter and the battery management system of the battery successfully communicate, the first charge and discharge strategy is enabled based on the battery type and the battery charge and discharge parameters. When the battery has no battery management system or the inverter and the battery management system of the battery do not successfully communicate, the second charge and discharge strategy is enabled based on the battery type and the battery charge and discharge parameters, so that the inverter can adapt to the use of different types of batteries, improve the robustness of the inverter to the battery, and its charge and discharge management of different types of batteries is safer, more accurate and efficient, greatly reducing various problems caused by unreasonable battery charge and discharge control management strategies, and improving the utilization efficiency of the battery and the cycle life of the battery under the premise of safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The scheme of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, in which:

[0057] Figure 1 It is a flow chart of an embodiment of a battery charge and discharge management method based on an inverter provided by the present invention;

[0058] Figure 2 is a flow chart of an embodiment of the first charging strategy provided by the present invention;

[0059] Figure 3 is a flow chart of another embodiment of the first charging strategy provided by the present invention;

[0060] Figure 4 is a flow chart of an embodiment of a second charging strategy provided by the present invention;

[0061] Figure 5 is a flow chart of another embodiment of the second charging strategy provided by the present invention;

[0062] Figure 6 is a flow chart of an embodiment of the first discharge strategy provided by the present invention;

[0063] Figure 7 is a flow chart of an embodiment of the second discharge strategy provided by the present invention;

[0064] Figure 8 It is a module schematic diagram of an embodiment of a battery charge and discharge management system provided by the present invention;

[0065] Fig. 9is a module schematic diagram of an embodiment of an inverter provided by the present invention;

[0066] Fig.10 It is a module diagram of an embodiment of a computer-readable storage medium provided by the present invention.

[0067] The reference numerals in the figures are:

[0068] 100. Battery charge and discharge management system;

[0069] 101, acquisition module; 102, determination module; 103, first activation module; 104, second activation module;

[0070] 200, inverter;

[0071] 201, processor; 202, memory;

[0072] 300. Computer readable storage medium;

[0073] 301. Computer program. DETAILED DESCRIPTION

[0074] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. Now, in conjunction with the accompanying drawings, the preferred embodiments of the present invention are described in detail.

[0075] The embodiment of the present invention provides a battery charge and discharge management method based on an inverter, which is applied to an inverter, and the inverter can be connected to a battery.

[0076] refer to Figure 1 , the inverter-based battery charge and discharge management method includes:

[0077] S110, obtaining the battery type and corresponding battery charging and discharging parameters;

[0078] S120, determining whether the battery has a battery management system;

[0079] S130, if yes, determine whether the inverter successfully communicates with the battery management system of the battery;

[0080] S140, if the inverter successfully communicates with the battery management system of the battery, enabling a first charge and discharge strategy based on the battery type and battery charge and discharge parameters;

[0081] S150: If the battery does not have a battery management system or the inverter fails to communicate successfully with the battery management system of the battery, a second charge and discharge strategy is enabled based on the battery type and battery charge and discharge parameters.

[0082] The battery charge and discharge management method obtains the battery type and the corresponding battery charge and discharge parameters, and determines whether the battery has a battery management system and whether the inverter and the battery management system of the battery successfully communicate when the battery has a battery management system. When the inverter and the battery management system of the battery successfully communicate, a first charge and discharge strategy is enabled based on the battery type and the battery charge and discharge parameters. When the battery has no battery management system or the inverter and the battery management system of the battery do not successfully communicate, a second charge and discharge strategy is enabled based on the battery type and the battery charge and discharge parameters, so that the inverter can adapt to the use of different types of batteries, improve the robustness of the inverter to the battery, and its charge and discharge management of different types of batteries is safer, more accurate and efficient, which greatly reduces various problems caused by unreasonable battery charge and discharge control management strategies, and improves the utilization efficiency of the battery and the cycle life of the battery under the premise of safety.

[0083] Among them, the battery management system (BMS) of the battery is an electronic system that is specifically responsible for monitoring and managing the operating status of rechargeable batteries (whether a single battery or a battery pack), which can monitor battery voltage, battery current and other parameters. The inverter successfully communicates with the battery management system of the battery, and can obtain the battery voltage, battery current and other parameters monitored by the battery management system. Of course, it is necessary to first configure the relevant parameters for communication with the battery management system on the inverter so that the inverter can successfully communicate with the battery management system to obtain relevant data of the battery. The battery management system can also transmit the charging fault status to the inverter, and the inverter will cut off the charging of the battery according to the charging fault status. Among them, the charging fault status can also be divided into levels, and the inverter can be set to shield some levels of charging fault status, so as to further be compatible with the charging and discharging strategies of different types of batteries.

[0084] In step S110, when the inverter is connected to the battery for the first time, the user can input the battery type, that is, the custom battery type. The inverter can obtain the input battery type and obtain the corresponding battery charge and discharge parameters according to the battery type. The inverter automatically initializes the relevant parameters of the battery, such as initializing the relevant parameters of the lithium battery, initializing the relevant parameters of the associated balanced charge based on other custom battery types, etc., to determine the battery charge and discharge depth and control logic, and enable the corresponding specific charge and discharge strategy, so that the inverter can achieve accurate charge and discharge management of different types of batteries.

[0085] In an optional embodiment of the present application, if the inverter fails to communicate with the battery management system of the battery, it can further determine whether the battery output is allowed. If the battery output is not allowed, the battery output is controlled to be cut off.

[0086] refer to Figure 2 In this embodiment, the first charge-discharge strategy includes a first charging strategy, and the first charging strategy includes the following steps:

[0087] S210, controlling constant current charging of the battery;

[0088] S220, controlling the constant current charging to be converted into constant voltage charging or stopping charging according to the battery capacity and the battery voltage and battery current transmitted in real time by the battery management system.

[0089] When the battery starts to charge, the internal resistance of the battery is usually large. By charging the battery with a constant current at the beginning of the charging stage, the current can be ensured to be stable and the battery voltage fluctuation can be reduced. Constant current charging can also allow the battery to charge quickly with a large current, thereby shortening the charging time and improving the charging efficiency. Further, according to the battery capacity and the battery voltage and battery current transmitted in real time by the battery management system, the constant current charging is controlled to be converted into constant voltage charging or stopped. The charging current of the battery can be adjusted reasonably and timely, the appropriate charging state of the battery can be controlled, and overvoltage failure of the battery can be avoided to truly charge the battery.

[0090] Specifically, refer to Figure 3 Step S220 controls the constant current charging to be converted into constant voltage charging or stops charging according to the battery capacity and the battery voltage and battery current transmitted in real time by the battery management system, and specifically includes the following steps:

[0091] S310, determining whether the battery capacity is greater than the stop charging capacity point;

[0092] S320, if the battery capacity is not greater than the stop charging capacity point, determine whether the battery voltage is less than the constant voltage charging voltage point;

[0093] S330, if the battery voltage is lower than the constant voltage charging voltage point, continue to control the constant current charging of the battery;

[0094] S340, if the battery voltage is not less than the constant voltage charging voltage point, control the battery to be charged at a constant voltage;

[0095] S350, in a constant voltage charging mode, determining whether the battery current is less than a stop charging current point;

[0096] S360: If the battery current is less than the stop charging current point, charging is completed;

[0097] S370: If the battery current is not less than the stop charging current point, continue to control the constant voltage charging of the battery.

[0098] In step S310, if the battery capacity is greater than the stop charging capacity point, charging is completed.

[0099] The above first charging strategy is for the case where the battery has a battery management system and the battery management system successfully communicates with the inverter. The battery is usually a lithium battery. Different lithium batteries have different stop charging capacity points, and the stop charging capacity point can also be set as needed.

[0100] By first judging the battery capacity, stopping charging when the battery capacity is greater than the stop charging capacity point to avoid overcharging, and then adjusting to constant voltage charging based on the battery voltage to avoid safety problems caused by abnormal voltage. After switching to constant voltage charging, the charging speed will gradually slow down, which helps to charge the battery more fully. Finally, judging whether to stop charging based on the battery current to avoid overcharging the battery. Therefore, the above charging strategy can ensure that the entire charging process can adapt to the battery type, that is, lithium battery charging, making lithium battery charging safer, more accurate and efficient.

[0101] In the first charging strategy, during the process of controlling the constant current charging of the battery, the current limiting mode can be entered to limit the charging current. In the current limiting mode, there are three current limiting charging strategies. Users can customize different current limiting charging strategies. The inverter obtains the current limiting charging strategy selection and enables the corresponding current limiting charging strategy. The three current limiting charging strategies include the first current limiting charging strategy, the second current limiting charging strategy, and the third current limiting charging strategy.

[0102] The first current limiting charging strategy includes the following steps:

[0103] Get the preset maximum charging current uploaded by the battery management system;

[0104] Limiting the charging current of the battery according to the preset maximum charging current;

[0105] If the maximum charging current preset by the battery management system is greater than the maximum charging current supported by the inverter, the charging current of the battery is limited by the maximum charging current supported by the inverter.

[0106] The second current limiting charging strategy includes the following steps:

[0107] Get the maximum charging current supported by the inverter;

[0108] Set the battery charging current according to the battery state of charge.

[0109] The charging current of the battery is set according to the battery state of charge. Specifically, when the battery state of charge is lower than 85%, the charging current of the battery is limited to the maximum charging current supported by the inverter; when the battery state of charge is greater than or equal to 85% and less than 90%, the charging current of the battery is limited to half of the maximum charging current supported by the inverter; when the battery state of charge is greater than or equal to 90% and less than 95%, the charging current of the battery is limited to one quarter of the maximum charging current supported by the inverter; when the battery state of charge is greater than or equal to 95% and less than 98%, the charging current of the battery is limited to one eighth of the maximum charging current supported by the inverter; when the battery state of charge is greater than or equal to 98%, the charging current of the battery is limited to one sixteenth of the maximum charging current supported by the inverter. The above second current limiting charging strategy can make battery charging safer.

[0110] The third current limiting charging strategy includes the following steps:

[0111] Get the preset fixed current limit value;

[0112] A fixed current limit value is used to limit the battery charging current.

[0113] The user can customize the fixed current limit value as needed, and the set value is less than or equal to the maximum charging current supported by the inverter.

[0114] In this embodiment, the second charge and discharge strategy includes a second charging strategy, referring to Figure 4 , the second charging strategy includes the following steps:

[0115] S410, controlling constant current charging of the battery;

[0116] S420, converting constant current charging into constant voltage charging according to the sampled battery voltage and battery type;

[0117] S430: In a constant voltage charging mode, the battery is charged according to the battery type and the sampled battery voltage and battery current.

[0118] The above-mentioned second charging strategy is aimed at the situation where the battery does not have a battery management system or the inverter and the battery management system of the battery cannot communicate successfully. Batteries without a battery management system usually include colloidal batteries, sealed lead-acid batteries, open lead-acid batteries or other user-defined battery types, and batteries with a battery management system are usually lithium batteries.

[0119] The inverter can obtain real-time battery voltage and battery current through internal circuit sampling, convert constant current charging into constant voltage charging according to the battery voltage and battery type, and charge the battery in constant voltage charging mode according to the battery type and the sampled battery voltage and battery current control, which can effectively control the battery charging, intelligently adjust the charging method and improve the charging efficiency.

[0120] refer to Figure 5 In this embodiment, in step S430, charging is performed according to the battery type and the battery current obtained by sampling, which specifically includes the following steps:

[0121] S510, judging whether it is necessary to enable balanced charging according to the battery type;

[0122] S520, if necessary, controlling the battery to be balanced charged;

[0123] S530: If not necessary, control the battery to be charged.

[0124] S540, determining whether the battery current is less than the stop charging current point;

[0125] S550: If the battery current is less than the stop charging current point, the battery is controlled to be float charged.

[0126] By judging whether the battery needs balanced charging, and enabling balanced charging when it is needed, the charge state of each single cell is balanced, the battery life is extended, and the charging efficiency is improved; if it is judged that the battery does not need balanced charging, the battery is charged by boost charging, which can speed up the overall charging speed. Further judge the battery current, and enable floating charge when the battery current is less than the stop charging current point. Floating charge can maintain the stability of the battery in the full state, avoid overcharging and over-discharging, and extend the battery life. Floating charge can continuously charge the battery in the battery standby state to ensure that the battery can be used at any time. It is suitable for batteries that need to be stored for a long time. Especially for some batteries such as storage batteries, the storage battery can be fully charged in a real sense to avoid the situation where the storage battery is fully charged and then discharged for a while and then enters a low power state.

[0127] Furthermore, after controlling the battery to be float charged, the following steps are also included:

[0128] S560, determining whether the sampled battery voltage is less than the floating charge voltage point, and determining whether the floating charge time is greater than the floating charge delay time;

[0129] S570: If the battery voltage is greater than the floating charge voltage point, determine whether the sampled battery current is less than the stop charging current point;

[0130] S580: If the battery current is less than the stop charging current point or the floating charge time is greater than the floating charge delay time, the charging is completed.

[0131] By comparing the battery voltage sampled by the inverter with the preset floating charge voltage point, and the floating charge time with the preset floating charge delay time, it can ensure that the battery voltage is kept within a safe range during the floating charge stage, and control the duration of floating charge to avoid overcharging, reduce battery loss, and improve charging efficiency and safety. In addition, when the battery voltage is greater than the floating charge voltage point, the battery current is monitored to ensure that appropriate charging control continues when the battery is fully charged, avoiding overcharging or over-discharging and protecting battery safety.

[0132] refer to Figure 6 In this embodiment, the first charge-discharge strategy also includes a first discharge strategy, and the first discharge strategy includes the following steps:

[0133] S610, determining whether the battery capacity is lower than the stop discharge capacity point;

[0134] S620, when the inverter is not in the mains priority mode and is not in the photovoltaic pre-mode, if the battery capacity is not less than the stop discharge capacity point, determine whether the battery capacity is less than the mains switching capacity point and whether the mains is connected, and determine whether the battery capacity is higher than the battery switching capacity point and whether it is in the mains bypass state;

[0135] S630: If the battery capacity is lower than the AC power switching capacity point and the AC power is connected, the battery is controlled to stop discharging and the AC power bypass is switched to carry the load;

[0136] S640: If the battery capacity is higher than the battery switching capacity point and the battery is in the AC bypass state, the battery is controlled to resume discharge and the battery inverter is switched to carry the load.

[0137] In step S610, if the battery capacity is lower than the stop discharge capacity point, the battery is controlled to stop discharging.

[0138] The above-mentioned first discharge strategy is for the case where the battery has a battery management system and the battery management system successfully communicates with the inverter. The battery is usually a lithium battery. Different lithium batteries have different stop charging capacity points. Of course, the stop charging capacity point can also be set as needed.

[0139] The first discharge strategy described above can effectively manage the discharge process of the battery, ensuring that the battery can be appropriately switched and controlled according to the real-time status during discharge, so as to ensure the safe operation and maximum utilization of the battery.

[0140] Specifically, by judging whether the battery capacity is lower than the stop discharge capacity point, the battery capacity can be monitored to ensure that the discharge is stopped when the battery capacity is lower than the set stop discharge capacity point, so as to avoid excessive discharge damage to the battery. Judging whether the battery capacity is lower than the mains switching capacity point and whether the mains is connected, and judging whether the battery capacity is higher than the battery switching capacity point and whether it is in the mains bypass state, is used to monitor the battery capacity and mains state to decide whether to continue discharging or switch to the mains power supply or bypass state, so that when the battery capacity is low, it can be switched to the mains bypass load in time to prevent the battery from being in a power-deficient state after the power grid is out of power, and when the battery capacity is high, it can be switched back to the battery inverter load, so that when there is excess photovoltaic energy, it can be stored in the battery to avoid wasting excess photovoltaic energy.

[0141] Among them, it can be set that when the battery capacity is greater than the stop discharge capacity point by more than 10% of the stop discharge capacity point, the battery is controlled to resume output and consume the battery energy so that when there is excess photovoltaic energy, the energy can be stored in the battery.

[0142] refer to Figure 7 In this embodiment, the second charge and discharge strategy includes a second discharge strategy, and the second discharge strategy includes the following steps:

[0143] S710, when the inverter is not in the mains priority mode and is not in the photovoltaic pre-mode, determining whether the sampled battery voltage is lower than the mains switching voltage point and whether the mains is connected, and determining whether the battery voltage is higher than the battery switching voltage point and whether it is in the mains bypass state;

[0144] S720: If the battery voltage is lower than the AC power switching voltage point and the AC power is connected, the battery is controlled to stop discharging and the AC power bypass is switched to carry the load;

[0145] S730: If the battery voltage is higher than the battery switching voltage point and is in the AC bypass state, the battery is controlled to resume discharging and the battery inverter is switched to carry the load.

[0146] The above-mentioned second discharge strategy is aimed at the situation where the battery does not have a battery management system or the inverter and the battery management system of the battery cannot communicate successfully. Batteries without a battery management system usually include colloidal batteries, sealed lead-acid batteries, and open lead-acid batteries. Batteries with a battery management system are usually lithium batteries.

[0147] The second discharge strategy can effectively manage the battery discharge process according to the battery voltage and the mains power status, ensuring that the battery can be appropriately switched and controlled according to the real-time status during discharge to ensure the safe operation and maximum utilization of the battery.

[0148] Specifically, when the battery voltage is lower than the AC switching voltage point and the AC power is connected, it is switched to the AC bypass load and the battery is charged according to the charging mode to prevent the battery from being in a low-power state after a power outage; when the battery voltage is higher than the battery switching voltage point and is in the AC bypass state, the battery is switched to the inverter load, the battery resumes discharging, and the battery energy is consumed, so that when there is excess photovoltaic energy, it can be stored in the battery to avoid wasting excess photovoltaic energy.

[0149] In this embodiment, before determining whether the battery has a battery management system, the following steps are also included:

[0150] When the inverter is not in the mains priority mode and not in the photovoltaic pre-mode, it is determined whether the sampled battery voltage is lower than the over-discharge limit voltage point;

[0151] If the battery voltage is not lower than the over-discharge limit voltage point, determine whether the battery voltage is lower than the over-discharge limit voltage point and lasts for the over-discharge delay time;

[0152] If the battery voltage is lower than the over-discharge limit voltage point and continues for the over-discharge delay time, or the battery voltage is lower than the over-discharge limit voltage point, it is determined whether the AC power is connected. If the AC power is connected, the battery is controlled not to discharge, and the AC power bypass is loaded. If the AC power is not connected, the battery is controlled not to discharge.

[0153] By comparing the battery voltage with the over-discharge limit voltage point and controlling the battery discharge based on the over-discharge delay time, the battery can be prevented from being shut down by mistake due to instantaneous high-power loading. Specifically, when the load power increases instantaneously, the battery voltage will also be pulled down instantaneously. It is wrong to shut down the battery at this time, because the current battery may not be in a low-power state, and the voltage may gradually recover. Therefore, based on the comparison of the battery voltage with the over-discharge limit voltage point and the continuous over-discharge delay time to control the battery discharge, the inverter will cut off the battery output only after the battery voltage is lower than the over-discharge limit voltage point and continues for the over-discharge delay time, so as to cut off the battery output at the appropriate time, avoid the battery from being shut down by mistake due to instantaneous high-power loading, and protect the battery to the maximum extent.

[0154] When the inverter is in the mains priority mode, it determines whether the mains is connected. If the mains is connected, the mains bypass is controlled to carry the load, and the battery does not discharge. When the inverter is in the photovoltaic priority mode, it determines whether the photovoltaic is connected. If the photovoltaic is connected, it determines whether the battery voltage is lower than the over-discharge limit voltage point, and continues to execute the subsequent steps after the determination. If there is no photovoltaic connection, it determines whether the mains is connected. If the mains is connected, the mains bypass is controlled to carry the load, and the battery does not discharge.

[0155] In this embodiment, before determining whether the battery has a battery management system, the following steps are also included:

[0156] Determine whether to set timed charging and discharging;

[0157] If yes, determine whether it is in the time period of scheduled charge and discharge. If it is in the time period of scheduled charge and discharge or the time period of scheduled charge and discharge is not set, determine whether the battery has a battery management system.

[0158] If it is not in the timed charge and discharge time period, the charge and discharge will not be started.

[0159] In the timed charge and discharge mode, the inverter will perform corresponding charge and discharge actions according to the timed charge and discharge time period set by the user. This function is mainly used to utilize the peak-valley electricity price difference to achieve the benefits of peak-shaving and valley-filling. By judging whether to set the timed charge and discharge, the inverter can be controlled to start charging and discharging in the set time period, and not to start charging and discharging in the unnecessary time period, so as to reasonably control the charging and discharging of the battery, avoid the waste of photovoltaic energy, and achieve the benefits of peak-shaving and valley-filling.

[0160] In an optional embodiment of the present application, before determining whether the battery has a battery management system, the following steps are further included:

[0161] Determine whether a battery is connected;

[0162] If a battery is connected, determine whether the battery is a battery management system;

[0163] If there is no battery, it enters the no-battery mode.

[0164] The inverter-based battery charge and discharge management method of this application enables users to use the inverter without being limited to the type of connected batteries, and has more choices in the use of batteries, reducing the user's investment cost in energy storage. The rich control parameters and support for custom adjustments make the inverter more compatible with the battery charge and discharge management, breaking the "rule" that the inverter must be used after being coordinated with the battery. At the same time, because the inverter can enable corresponding charge and discharge strategies for different batteries, the inverter is safer, more accurate and more efficient in the control and management of battery charge and discharge, which not only improves the battery's cycle life, but also greatly reduces the various problems caused by unreasonable battery charge and discharge control management strategies. Without increasing any cost, the user experience is greatly improved.

[0165] refer to Figure 8 The embodiment of the present application further provides a battery charge and discharge management system 100, which applies the above-mentioned battery discharge management method to implement battery charge and discharge management. The battery charge and discharge management system 100 includes the following modules:

[0166] An acquisition module 101 is used to acquire a battery type and corresponding battery charge and discharge parameters;

[0167] A determination module 102 is used to determine whether the battery has a battery management system and whether the inverter 200 successfully communicates with the battery management system of the battery;

[0168] A first enabling module 103, configured to enable a first charging and discharging strategy based on the battery type and the battery charging and discharging parameters if the inverter 200 successfully communicates with the battery management system of the battery;

[0169] The second enabling module 104 is configured to enable a second charge and discharge strategy based on the battery type and the battery charge and discharge parameters if the battery has no battery management system or the inverter 200 fails to communicate with the battery management system of the battery.

[0170] The battery charge and discharge management system 100 has the same technical effects as the above-mentioned battery charge management method, which will not be described in detail here.

[0171] refer to Fig. 9 The embodiment of the present application further provides an inverter 200, the inverter 200 includes a processor 201 and a memory 202. The processor is coupled to the memory 202. The memory 202 stores a computer program 301, and the processor executes the computer program 301 when working to implement the above method. The detailed steps can be referred to above, and will not be repeated here.

[0172] refer to Fig.10 , the embodiment of the present application also provides a computer-readable storage medium 300, in which at least one computer program 301 is stored, and the computer program 301 is used to be executed by the processor to implement the above method. The detailed steps can be referred to above and will not be repeated here. In one embodiment, the computer-readable storage medium 300 can be a storage chip, a hard disk, or a mobile hard disk or a USB flash drive, a CD, or other readable and writable storage tools in the terminal, or a server, etc.

[0173] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in the present application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0174] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0175] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the protection scope of the claims attached to the present invention.

Claims

1. A battery charge and discharge management method based on an inverter, applied to an inverter, wherein the inverter can be connected to a battery, characterized in that: The battery charge and discharge management method comprises: Get the battery type and corresponding battery charge and discharge parameters; Determine whether the battery has a battery management system; If so, determine whether the inverter successfully communicates with the battery management system of the battery; If the inverter successfully communicates with the battery management system of the battery, a first charge and discharge strategy is enabled based on the battery type and the battery charge and discharge parameters; If the battery does not have a battery management system or the inverter fails to communicate successfully with the battery management system of the battery, a second charge and discharge strategy is enabled based on the battery type and the battery charge and discharge parameters.

2. The battery charge and discharge management method according to claim 1, characterized in that: The first charge-discharge strategy includes a first charging strategy, and the first charging strategy includes the following steps: Control constant current charging of the battery; According to the battery capacity and the battery voltage and battery current transmitted in real time by the battery management system, the constant current charging is controlled to be converted into constant voltage charging or charging is stopped.

3. The battery charge and discharge management method according to claim 2, characterized in that: The method of controlling the constant current charging to be converted into constant voltage charging or stopping charging according to the battery capacity and the battery voltage and battery current transmitted in real time by the battery management system specifically includes the following steps: Determine whether the battery capacity is greater than the stop charging capacity point; If the battery capacity is greater than the stop charging capacity point, charging is complete; If the battery capacity is not greater than the stop charging capacity point, determine whether the battery voltage is less than the constant voltage charging voltage point; If the battery voltage is lower than the constant voltage charging voltage point, the battery will continue to be charged with a constant current; If the battery voltage is not less than the constant voltage charging voltage point, the control performs constant voltage charging on the battery. Under the constant voltage charging mode, it is determined whether the battery current is less than the stop charging current point; If the battery current is less than the stop charging current point, the charging is completed; If the battery current is not less than the stop charging current point, the battery will continue to be controlled to be charged at a constant voltage.

4. The battery charge and discharge management method according to claim 1, characterized in that: The second charge-discharge strategy includes a second charging strategy, and the second charging strategy includes the following steps: Control constant current charging of the battery; The constant current charging is converted into constant voltage charging according to the sampled battery voltage and battery type; In the constant voltage charging mode, the battery is charged according to the battery type and the battery voltage and battery current obtained by sampling.

5. The battery charge and discharge management method according to claim 4, characterized in that: The charging is performed according to the battery type and the battery current control obtained by sampling, and specifically includes the following steps: Determine whether equalization charging needs to be enabled based on the battery type; If necessary, the battery is controlled to be charged evenly; if not, the battery is controlled to be charged more vigorously; Determine whether the battery current is less than the stop charging current point; If the battery current is less than the stop charging current point, the control performs float charging on the battery.

6. The battery charge and discharge management method according to claim 5, characterized in that: After the control performs float charging on the battery, the following steps are also included: Determine whether the sampled battery voltage is less than the floating charge voltage point, and determine whether the floating charge time is greater than the floating charge delay time; If the battery voltage is greater than the floating charge voltage point, determine whether the sampled battery current is less than the stop charging current point; If the battery current is less than the stop charging current point and the floating charge time is greater than the floating charge delay time, the charging is completed.

7. The battery charge and discharge management method according to claim 1, characterized in that: The first charge and discharge strategy also includes a first discharge strategy, and the first discharge strategy includes the following steps: Determine whether the battery capacity is lower than the stop discharge capacity point; If the battery power is lower than the stop discharge capacity point, the battery is controlled to stop discharging; When the inverter is not in the mains priority mode and not in the PV pre-mode, if the battery capacity is not less than the stop discharge capacity point, it is determined whether the battery capacity is less than the mains switching capacity point and whether the mains is connected, and whether the battery capacity is greater than the battery switching capacity point and whether it is in the mains bypass state; If the battery capacity is lower than the AC power switching capacity point and the AC power is connected, the battery will be controlled to stop discharging and the AC power bypass will be switched to carry the load; If the battery capacity is higher than the battery switching capacity point and is in the AC bypass state, the battery is controlled to resume discharge and the battery inverter is switched to carry the load.

8. The battery charge and discharge management method according to claim 7, characterized in that: The second charge and discharge strategy includes a second discharge strategy, and the second discharge strategy includes the following steps: When the inverter is not in the mains priority mode and not in the photovoltaic pre-mode, determine whether the sampled battery voltage is lower than the mains switching voltage point and whether the mains is connected, and determine whether the battery voltage is higher than the battery switching voltage point and whether it is in the mains bypass state; If the battery voltage is lower than the AC power switching voltage point and the AC power is connected, the battery will be controlled to stop discharging and the AC power bypass will be switched to carry the load; If the battery voltage is higher than the battery switching voltage point and is in the AC bypass state, the battery is controlled to resume discharge and the battery inverter is switched to carry the load.

9. The battery charge and discharge management method according to claim 8, characterized in that: Before determining whether the battery has a battery management system, the following steps are also included: When the inverter is not in the mains priority mode and not in the photovoltaic pre-mode, it is determined whether the sampled battery voltage is lower than the over-discharge limit voltage point; If the battery voltage is not lower than the over-discharge limit voltage point, determine whether the battery voltage is lower than the over-discharge limit voltage point and lasts for the over-discharge delay time; If the battery voltage is lower than the over-discharge limit voltage point and continues for the over-discharge delay time, or the battery voltage is lower than the over-discharge limit voltage point, it is determined whether the AC power is connected. If the AC power is connected, the battery is controlled not to discharge, and the AC power bypass is loaded. If the AC power is not connected, the battery is controlled not to discharge.

10. A battery charge and discharge management system, characterized in that: The battery charge and discharge management system applies the battery discharge management method according to any one of claims 1 to 9 to implement battery charge and discharge management. The battery charge and discharge management system includes the following modules: An acquisition module is used to obtain the battery type and the corresponding battery charging and discharging parameters; A judgment module is used to determine whether the battery has a battery management system and whether the inverter successfully communicates with the battery management system of the battery; A first enabling module, configured to enable a first charge and discharge strategy based on the battery type and the battery charge and discharge parameters if the inverter successfully communicates with the battery management system of the battery; The second enabling module is used to enable a second charging and discharging strategy based on the battery type and the battery charging and discharging parameters if the battery has no battery management system or the inverter fails to communicate successfully with the battery management system of the battery.

Images