Energy storage frequency conversion device and charging and discharging control method

Abstract

The invention relates to the technical field of frequency conversion control, and particularly discloses an energy storage frequency conversion device and a charging and discharging control method.The energy storage frequency conversion device supports three-phase alternating current input and comprises a control part, a signal collecting and processing part, a main loop part and a battery part; the control part controls rectification, DCDC conversion and inversion of the energy storage frequency conversion device and charging and discharging of the battery part and is responsible for operation and processing of various collected signals. The signal acquisition and processing part comprises a three-phase input voltage acquisition module, a battery information acquisition module, a bus voltage acquisition module, a battery charging and discharging current acquisition module, an output current acquisition module, a DCDC driving module and a three-phase inversion driving module; the main loop part comprises a three-phase bridge type rectification part, a three-phase H-bridge inversion part and a DCDC part, and rectification, inversion and battery charging and discharging of the energy storage device are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of frequency conversion control, and more specifically, to an energy storage frequency conversion device and a charge and discharge control method. Background Art

[0002] In many industrial applications, the load power device is generally an electric motor, which is driven by a frequency converter. In some key process links, the load is not allowed to shut down, otherwise it will cause significant property losses or casualties. For key loads, the frequency converter is generally used in one standby mode, but it still cannot solve the problem of load shutdown caused by power failure in the power supply system.

[0003] The existing solutions are mainly the following three: They are: the diesel generator is used as a backup power source after the power supply system loses power; Configure PCS and energy storage system on the AC power supply side of the frequency converter. When the power supply system loses power, the energy storage system converts it into three-phase AC power through PCS to supply power to the AC side of the frequency converter. A DCDC converter is configured on the DC power supply side of the frequency converter to connect to the energy storage system. After the power supply system loses power, the energy storage system supplies power to the DC side of the frequency converter through the DCDC converter.

[0004] All of the above solutions have their drawbacks. The diesel generator power supply solution has the problems of long switching time and high system maintenance cost, and will cause environmental pollution during use; the AC side PCS solution has a complex system composition and relatively high cost; the DC side DCDC converter solution has lower costs than the AC side PCS, but requires real-time data interaction between the frequency converter and the DCDC converter, and the control is relatively complex; the traditional DCDC converter often fails to fully consider the dynamic voltage and current characteristics of the battery during the charging process, as well as the impact of environmental factors on the charging process. Summary of the invention

[0005] In order to overcome the above-mentioned defects of the prior art, the present invention provides an energy storage frequency conversion device and a charge and discharge control method, which is through the integrated design of the energy storage frequency conversion device. The energy storage frequency conversion device is composed of diode rectification, DC conversion, three-phase inverter and battery, which simplifies the composition of the system, realizes one control system to control three key parts, and has better real-time control and more efficient data transmission. At the same time, the integrated design of the energy storage frequency conversion device also reduces the system cost and is more economical; and the energy storage frequency conversion device provides a battery charging safety control model, which can ensure that the voltage and current of the battery during the charging process are always within a safe range by real-time monitoring and adjusting the output voltage and current of the DCDC converter, thereby solving the problems raised in the above-mentioned background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: an energy storage frequency conversion device, which is an integrated design of frequency converter and energy storage, including a main circuit part, a signal acquisition and processing part, a control part and a battery part, the main circuit part includes a three-phase bridge rectifier part, a three-phase H-bridge inverter part and a DCDC part, and the main circuit part is responsible for three-phase AC power conversion and energy distribution; the signal acquisition and processing part includes a three-phase input voltage acquisition module, a battery information acquisition module, a bus voltage acquisition module, a battery charge and discharge current acquisition module, an output current acquisition module, a DCDC drive module, and a three-phase inverter drive module; the control part controls the rectification and inversion of the energy storage frequency conversion device, and the charge and discharge management of the battery part; The DCDC part uses a battery charging safety control model to reduce the voltage on the DC bus and convert it into a voltage and current suitable for battery charging. The steps are as follows: Step Y1, input voltage of DCDC part and output voltage The dynamic changes between them are: ,in, is the inductance, is the current in the inductor, is the series resistance of the inductor; Step Y2: During the charging process, the battery voltage and current are not in a linear relationship. The battery gradually reaches its maximum charging voltage as the charging process progresses. The battery voltage is: , is the change of battery voltage over time, is the open circuit voltage of the battery, is the battery charging current, is the internal resistance of the battery; Step Y3, the DCDC part adjusts the duty cycle in real time , keep the output voltage and current within the safe charging range of the battery, the calculation formula is: ,in, is the change of duty cycle over time, is the target output voltage, is the proportionality coefficient, is the integration coefficient, is the differential coefficient.

[0007] As a further solution of the present invention, the main circuit part includes a three-phase bridge rectifier part, which converts the input three-phase AC into DC. The three-phase bridge rectifier part uses the unidirectional conductivity of the diode to realize the conversion of the positive and negative half cycles of the three-phase AC into DC voltage to obtain a smooth DC output. The three-phase bridge rectifier part directly supplies part of the energy of the three-phase AC to the three-phase H-bridge inverter part. The three-phase H-bridge inverter part inverts the DC into three-phase AC to drive the load motor to run. The main circuit part also includes a DCDC part, which plays the role of energy conversion between the battery and the DC bus. During the charging process, the DCDC part can convert the higher voltage on the DC bus into a voltage and current suitable for battery charging, ensuring that the battery can be charged safely and efficiently. During the discharge process, the DCDC part converts the lower voltage stored in the battery into a voltage that matches the DC bus voltage, so as to release the battery's electrical energy to the DC bus, provide energy for the three-phase H-bridge inverter part, and maintain the continuous operation of the load motor when the power supply system loses power.

[0008] As a further solution of the present invention, the signal acquisition and processing part includes a three-phase input voltage acquisition module, which monitors the three-phase AC voltage input to the energy storage frequency conversion device in real time and measures the amplitude, frequency and phase of each phase voltage; the battery information acquisition module is responsible for obtaining the power information of the battery part, and the battery part mainly realizes the storage of electric energy to ensure the energy supply after the power supply system loses power; the bus voltage acquisition module monitors the voltage value of the main circuit DC bus in real time, and the DC bus is respectively connected to the three-phase bridge rectifier part, the three-phase H-bridge inverter part and the DCDC part The battery charging and discharging current acquisition module is used to monitor the current size of the battery during the charging and discharging process in real time. The DCDC driving module is responsible for driving the IGBT of the DCDC conversion after processing the control signal transmitted by the control part; the three-phase inverter driving module is responsible for processing the control signal transmitted by the control part to provide drive for the three-phase H-bridge inverter part. The drive has a strict timing to ensure that the power switch tube can be turned on and off according to a predetermined rule. The signal acquisition and processing part also includes an output current acquisition module, which is used to collect the current signal output by the energy storage frequency conversion device to the load motor.

[0009] As a further solution of the present invention, the control part is connected to the three-phase input voltage acquisition module, the battery information acquisition module, the bus voltage acquisition module, the battery charge and discharge current acquisition module, the DCDC drive module, the three-phase inverter drive module, and the output current acquisition module respectively. The control part controls the inversion of the energy storage frequency conversion device, the charging and discharging of the battery part, and is responsible for the calculation and processing of various acquisition signals.

[0010] As a further solution of the present invention, a charging control method for an energy storage frequency conversion device comprises the following specific steps: Step S1, pre-setting the battery charging stop power (taking 90% as an example) and the charging loop width (taking 5% as an example) in the energy storage frequency conversion device, and the control system continuously detects the battery charge state; Step S2, when the battery power is lower than 90%, the energy storage frequency conversion device monitors the AC input side power supply. If the AC input side power supply is normal, the energy storage frequency conversion device further detects whether the AC side output power of the energy storage frequency conversion device reaches the rated value; Step S3, if the output current of the AC side does not reach the rated value, the energy storage frequency conversion device enters the charging state, and if the power output of the AC side is not less than the rated power of the energy storage frequency conversion device, the charging stops; Step S4, during the charging process, the energy storage frequency conversion device monitors the battery power status in real time, and when the battery charge reaches 90%, the charging stops. However, the energy storage frequency conversion device continues to detect the battery power, and once the battery power status is lower than 85%, the charging starts again.

[0011] As a further solution of the present invention, a discharge control method of an energy storage frequency conversion device comprises the following specific steps: Step Z1, pre-setting a battery discharge lower limit (taking 10% as an example) in the energy storage frequency conversion device, and the energy storage frequency conversion device continuously detects whether the power supply system loses power; Step Z2, when it is detected that the power supply system loses power, the energy storage frequency conversion device immediately detects whether the battery power is greater than the set discharge lower limit. If the battery power is greater than 10%, the energy storage frequency conversion device enters the discharge working state; Step Z3, during the discharge process, the energy storage frequency conversion device continuously monitors the battery power. When it is detected that the battery power is less than 10%, the battery discharge ends; Step Z4, after the battery discharge is completed, the energy storage frequency conversion device enters the standby mode, waiting for the power supply system to resume power supply or other subsequent operation instructions.

[0012] As a further solution of the present invention, there are two situations in the standby mode, which include the following specific steps: when the battery power reaches the set value and the battery power has not reached the lower limit of the ring width, the energy storage frequency conversion device is in standby mode; when the power supply system loses power and the charge state of the battery of the energy storage frequency conversion device is lower than 10%, the system enters standby mode.

[0013] As a further solution of the present invention, an energy storage frequency conversion device is applied to a scenario where a load motor works in four quadrants, and includes the following specific steps: Step Y1, setting the battery power lower limit, battery power upper limit, charging voltage and discharging voltage of the energy storage device; Step Y2: If the bus voltage is greater than the discharge voltage and less than the charge voltage, the battery is in a state of neither charging nor discharging. At this time, the system maintains the current energy balance state and continues to monitor the bus voltage and other related parameters. Step Y3, if the bus voltage is higher than the discharge voltage and the battery power does not exceed the upper limit, the battery enters the charging state and stores the excess power. At the same time, the battery power and bus voltage are continuously monitored to prevent overcharging abnormalities; Step Y4: If the bus voltage is lower than the discharge voltage and the battery power is not lower than the lower power limit, the battery starts to discharge to replenish energy for the system to maintain normal operation of the system. During the discharge process, pay close attention to the battery power to avoid over-discharge. Step Y5: In other cases, the energy storage device is shut down, and it is necessary to optimize the parameters of the working range and the bus charging and discharging voltage parameters according to the actual operating conditions of the load.

[0014] The technical effects and advantages of the energy storage frequency conversion device and the charge and discharge control method of the present invention are as follows: the present invention adopts an integrated design of frequency converter and energy storage, which is composed of diode rectification, DC conversion, three-phase inverter and battery, simplifies the system structure, realizes the control of multiple key parts through a control system, improves the control real-time performance and data transmission efficiency, and reduces the cost; the charging control method sets the battery stop charging power and charging loop width, charges when the battery power is lower than 90%, the AC input side power supply is normal, and the AC side output power does not reach the rated value, stops charging when the battery power is 90%, and starts again when the power is lower than 85%, which can effectively Manage battery charging; the discharge control method presets the lower limit of battery discharge. When the power supply system loses power and the battery power is greater than 10%, the battery discharges. When the power is less than 10%, the discharge ends and the system enters standby mode, ensuring that energy support is provided to the load motor when the power supply system loses power. When the load motor is applied to work in a four-quadrant scenario, it can automatically adjust the battery charge and discharge according to the bus voltage and battery power status to maintain system energy balance and avoid overcharging and over-discharging of the battery. It can also optimize the working range and bus charge and discharge voltage parameters according to the actual load conditions, providing a more stable, efficient and economical solution for the operation of load motors in industrial scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The figure is a schematic structural diagram of an energy storage frequency conversion device of the present invention.

[0016] Figure 2 The present invention is a schematic flow chart of a charging control method for an energy storage frequency conversion device.

[0017] Figure 3 The present invention is a schematic flow chart of a discharge control method for an energy storage frequency conversion device.

[0018] Figure 4 The present invention is a flow chart of an energy storage frequency conversion device applied to a load motor operating in a four-quadrant scenario. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Example 1

[0021] See also Figure 1As shown in the structural schematic diagram, an embodiment of the present invention provides an energy storage frequency conversion device, which supports the input connection of three-phase alternating current. The energy storage frequency conversion device includes a main circuit part, and the main circuit part includes a three-phase bridge rectifier part. The three-phase bridge rectifier part converts the input three-phase alternating current into direct current. At the same time, the three-phase bridge rectifier part uses the unidirectional conductivity of the diode to turn on each phase of the three-phase alternating current voltage in the positive half cycle, so that the current flows to the positive electrode of the DC bus, and is cut off in the negative half cycle, thereby realizing the conversion of the positive and negative half cycles of the three-phase alternating current into a DC voltage, and obtaining a relatively smooth DC output. The three-phase bridge rectifier part directly supplies a part of the energy of the three-phase alternating current to the positive electrode of the DC bus located at The three-phase H-bridge inverter part on the right side of the three-phase bridge rectifier part inverts DC power into three-phase AC power to drive the load motor to run. The three-phase H-bridge inverter part adjusts the frequency, phase and amplitude of the output three-phase AC power so that the load motor can run at a predetermined speed and torque. The main circuit part also includes a DCDC part, which plays a role in energy conversion between the battery and the DC bus. During the charging process, the DCDC part converts the higher voltage on the DC bus into a voltage and current suitable for battery charging through a battery charging safety control model to ensure that the battery can be charged safely and efficiently. The specific steps of the battery safety control model are as follows: Step Y1, the principle of the DCDC part is a buck converter, whose input voltage and output voltage The formula for dynamic changes between is: ,in, is the inductance, is the current in the inductor, is the series resistance of the inductor; the relationship between the voltage change and current of the DCDC part capacitor is: , is the capacitance of the capacitor, is the voltage of the capacitor, is the output current, is the current of the capacitor.

[0022] Step Y2, the output voltage of the DCDC part changes with time, and the calculation formula is: ,in, is a time-integrated variable, indicating the response speed of the DCDC part in adjusting the output voltage, which depends on the combined characteristics of the inductor and capacitor. is the input voltage, is the maximum charging voltage of the battery.

[0023] Step Y3: During the charging process, the battery voltage and current are not in a linear relationship. The battery will gradually reach its maximum charging voltage as the charging process progresses. The battery voltage calculation formula is: , is the change of battery voltage over time, is the open circuit voltage of the battery, is the battery charging current, is the internal resistance of the battery.

[0024] Step Y4, the DCDC part uses a feedback control system to adjust the duty cycle in real time To keep the output voltage and current within the safe charging range of the battery, the dynamic response formula of the feedback control system is: ,in, is the change of duty cycle over time, is the target output voltage, is the proportionality coefficient, is the integration coefficient, is the differential coefficient.

[0025] During the discharge process, the DCDC part converts the lower voltage stored in the battery into a voltage that matches the DC bus voltage, so as to release the battery's electrical energy to the DC bus, provide energy for the three-phase H-bridge inverter part, and maintain the continuous operation of the load motor when the power supply system loses power.

[0026] The energy storage frequency conversion device includes a signal acquisition and processing part, which includes a three-phase input voltage acquisition module. The three-phase input voltage acquisition module monitors the three-phase AC voltage input to the energy storage frequency conversion device in real time, and measures the amplitude, frequency and phase of each phase voltage. A battery information acquisition module is arranged on the right side of the three-phase input voltage acquisition module. The battery information acquisition module is responsible for obtaining the power information of the battery part. The battery part mainly realizes the storage of electric energy to ensure the energy supply after the power supply system loses power. In addition to collecting the power information, the battery information acquisition module also monitors the temperature and internal resistance and other parameters of the battery. The temperature and internal resistance and other parameters can reflect the health status of the battery. A bus voltage acquisition module is arranged on the right side of the battery information acquisition module. The bus voltage acquisition module monitors the voltage value of the DC bus of the main circuit in real time. The busbar is connected to the three-phase bridge rectifier part, the three-phase H-bridge inverter part and the DCDC part respectively. A battery charge and discharge current acquisition module is arranged on the right side of the busbar voltage acquisition module. The battery charge and discharge current acquisition module is used to monitor the current size of the battery in the charging and discharging process in real time. A DCDC drive module is arranged on the right side of the battery charge and discharge current acquisition module. The DCDC drive module is responsible for generating a control signal. A three-phase inverter drive module is arranged on the right side of the DCDC drive module. The three-phase inverter drive module provides a drive signal for the three-phase H-bridge inverter part. The drive signal has a strict timing and a suitable voltage and current amplitude to ensure that the power switch tube can be turned on and off according to a predetermined rule. The signal acquisition and processing part also includes an output current acquisition module, and the output current acquisition module is used to collect the current signal output by the energy storage frequency conversion device to the load motor.

[0027] The energy storage frequency conversion device also includes a control part, which is respectively connected to the three-phase input voltage acquisition module, the battery information acquisition module, the bus voltage acquisition module, the battery charge and discharge current acquisition module, the DCDC drive module, the three-phase inverter drive module, and the output current acquisition module. The control part controls the inversion of the energy storage frequency conversion device, the charging and discharging of the battery part, and is responsible for the calculation and processing of various acquisition signals.

[0028] Example 2

[0029] See also Figure 2 As shown in the flow chart, in this embodiment, the present invention provides a charging control method for an energy storage frequency conversion device, including the following contents: The energy storage frequency conversion device sets the battery stop charging power and charging loop width. The energy storage frequency conversion device can detect the battery power to perform charging actions, for example, the stop charging power is set to 90%. After the control system detects that the battery charge state is lower than 90%, it detects whether the AC input side power supply of the device is normal. After detecting that the grid voltage is normal, the energy storage frequency conversion device adopts the power distribution mode to charge the internal battery. Detect whether the AC side output power of the energy storage frequency conversion device reaches the rated value. If the AC side output current reaches the rated value, the energy storage frequency conversion device is charged. The charging mode is the current control mode. The charging power is the rated power of the energy storage frequency conversion device minus the AC side output power. If the AC side output power is not less than the rated power of the energy storage frequency conversion device, the charging stops. In order to ensure the frequent switching of the charging and discharging of the battery of the energy storage frequency conversion device, the energy storage frequency conversion device uses the hysteresis loop mode. The energy storage frequency conversion device can set the charge state loop width, for example, the loop width is set to 5%. After the battery charging reaches 90%, the charging stops. The energy storage frequency conversion device detects the battery power state in real time. After the battery power state is lower than 85%, the charging starts again.

[0030] Example 3

[0031] See also Figure 3 As shown in the flow chart, in this embodiment, the embodiment of the present invention provides a discharge control method for an energy storage frequency conversion device, including the following contents: to ensure the battery life of the energy storage frequency conversion device, the energy storage frequency conversion device can set a lower limit for battery discharge, for example, the lower limit for battery discharge is set to 10%, after the energy storage frequency conversion device detects that the power supply system loses power, the energy storage frequency conversion device detects whether the battery power is greater than 10%, if the battery power is greater than 10%, the energy storage frequency conversion device enters a discharge working state to ensure continuous operation of the equipment after the power supply system loses power, and when the battery power is detected to be lower than 10%, the battery discharge ends, and the energy storage frequency conversion device enters a standby mode.

[0032] Example 4

[0033] See also Figure 4As shown in the flow diagram, in this embodiment, the embodiment of the present invention provides an energy storage frequency conversion device applied to a scenario where the load motor works in the four quadrants, including the following contents: in the four-quadrant working mode, the DCDC works in the voltage loop mode, and it is necessary to set the battery power working lower limit and the battery power working upper limit of the energy storage frequency conversion device, and set the charging voltage and the discharging voltage of the energy storage frequency conversion device. When the bus voltage of the energy storage frequency conversion device is greater than the discharge voltage and less than the charging voltage, the battery is neither charged nor discharged; when the bus voltage of the energy storage frequency conversion device is higher than the discharge voltage and the battery power does not exceed the upper limit of power, the battery is charged and discharged, and when the bus voltage of the energy storage frequency conversion device is lower than the discharge voltage and the battery power is not lower than the lower limit of power, the battery is discharged. In other cases, the energy storage frequency conversion device is shut down, and it is necessary to optimize the point working interval parameters and the bus charging and discharging voltage parameters according to the actual operating conditions of the load.

[0034] The present invention provides an energy storage frequency conversion device and a charge and discharge control method, which adopts an integrated design of frequency converter and energy storage, and is composed of diode rectification, DC conversion, three-phase inversion and battery, simplifies the system structure, and realizes control of multiple key parts through a control system, which not only improves the real-time control and data transmission efficiency, but also reduces the cost; the charging control method sets the battery charging stop power and charging loop width, and starts charging when the battery power is lower than 90%, the AC input side power supply is normal, and the AC side output power does not reach the rated value, stops charging when charging reaches 90%, and starts again when it is lower than 85%, thereby realizing battery charging. Effective management; the discharge control method presets the lower limit of battery discharge. When the power supply system loses power and the battery power is greater than 10%, discharge is carried out. When the power is less than 10%, discharge is stopped and the system enters standby mode, which effectively guarantees the energy supply to the load motor when the power supply system loses power. When the load motor is applied to work in the four-quadrant scenario, it can automatically adjust the battery charge and discharge according to the bus voltage and battery power status to maintain the system energy balance and avoid overcharging and over-discharging of the battery. It can also optimize the working range and bus charge and discharge voltage parameters according to the actual load conditions, providing a more stable, efficient and economical solution for the operation of load motors in industrial scenarios.

[0035] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0036] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An energy storage frequency conversion device, comprising a main circuit part, a signal acquisition and processing part, a control part and a battery part, characterized in that: The main circuit part includes a three-phase bridge rectifier part, a three-phase H-bridge inverter part and a DCDC part. The main circuit part is responsible for three-phase AC conversion and energy distribution; the signal acquisition and processing part includes a three-phase input voltage acquisition module, a battery information acquisition module, a bus voltage acquisition module, a battery charge and discharge current acquisition module, an output current acquisition module, a DCDC drive module, and a three-phase inverter drive module; the control part controls the rectification, inversion and charging and discharging of the battery part of the energy storage frequency conversion device; The DCDC part uses a battery charging safety control model to reduce the voltage on the DC bus and convert it into a voltage and current suitable for battery charging. The steps are as follows: Step Y1, the input voltage of the DCDC part and output voltage The dynamic changes between them are: ,in, is the inductance, is the current in the inductor, is the series resistance of the inductor; Step Y2: During the charging process, the battery voltage and current are not in a linear relationship. The battery gradually reaches its maximum charging voltage as the charging process progresses. The battery voltage is: , is the change of battery voltage over time, is the open circuit voltage of the battery, is the battery charging current, is the internal resistance of the battery; Step Y3, the DCDC part adjusts the duty cycle in real time , keep the output voltage and current within the safe charging range of the battery, the calculation formula is: ,in, is the change of duty cycle over time, is the target output voltage, is the proportionality coefficient, is the integration coefficient, is the differential coefficient.

2. An energy storage frequency conversion device according to claim 1, characterized in that: The three-phase bridge rectifier part converts the input three-phase AC power into DC power, and the three-phase bridge rectifier part directly supplies a part of the energy of the three-phase AC power to the three-phase H-bridge inverter part located on the right side of the three-phase bridge rectifier part. The three-phase H-bridge inverter part inverts the DC power into three-phase AC power to drive the load motor to operate. The main circuit part also includes a DCDC part, and the DCDC part plays a role in energy conversion between the battery and the DC bus.

3. The energy storage frequency conversion device according to claim 1, characterized in that The three-phase input voltage acquisition module monitors the three-phase AC voltage input to the energy storage frequency conversion device in real time, and measures the amplitude, frequency and phase of each phase voltage; the battery information acquisition module is responsible for obtaining the power information of the battery part, realizing the storage and release of the electric energy of the battery part, and ensuring the energy supply after the power supply system loses power; the bus voltage acquisition module monitors the voltage value of the main circuit DC bus in real time.

4. The energy storage frequency conversion device according to claim 3, characterized in that The DC bus is connected to the three-phase bridge rectifier part, the three-phase H-bridge inverter part and the DCDC part respectively; the battery charging and discharging current acquisition module is used to monitor the current size of the battery in real time during the charging and discharging process; the DCDC drive module is responsible for processing the control signal transmitted by the control part and then driving the IGBT of the DCDC conversion; the three-phase inverter drive module is responsible for processing the control signal transmitted by the control part to provide drive for the three-phase H-bridge inverter part, and the drive has a strict timing to ensure that the power switch tube can be turned on and off according to a predetermined rule; the signal acquisition and processing part also includes an output current acquisition module, and the output current acquisition module is used to collect the current signal output by the energy storage frequency conversion device to the load motor.

5. The energy storage frequency conversion device according to claim 1, characterized in that The control part is connected to the three-phase input voltage acquisition module, the battery information acquisition module, the bus voltage acquisition module, the battery charge and discharge current acquisition module, the DCDC drive module, the three-phase inverter drive module, and the output current acquisition module respectively. The control part controls the rectification and inversion of the energy storage frequency conversion device, the charging and discharging of the battery part, and is responsible for the calculation and processing of various acquisition signals.

6. The energy storage frequency conversion device according to claim 1, characterized in that ,The three-phase bridge rectifier part utilizes the unidirectional conductivity of the diode to convert both the positive and negative half cycles of the three-phase alternating current into a DC voltage to obtain a smooth DC output.

7. The energy storage frequency conversion device according to claim 1, characterized in that During the charging process, the DCDC part can convert the high voltage on the DC bus into a voltage and current suitable for battery charging. During the discharging process, the DCDC part can convert the low voltage stored in the battery into a voltage that matches the DC bus voltage, so as to release the battery's electrical energy to the DC bus, provide energy for the three-phase H-bridge inverter part, and maintain the continuous operation of the load motor when the power supply system loses power.

8. A charging control method for an energy storage frequency conversion device, applied to an energy storage frequency conversion device according to any one of claims 1 to 7, comprising the following steps: Step S1, pre-setting the battery charging stop power (taking 90% as an example) and the charging loop width (taking 5% as an example) in the energy storage frequency conversion device, and the control system continuously detects the battery charge state; Step S2, when the battery power is lower than 90%, the energy storage frequency conversion device monitors the AC input side power supply. If the AC input side power supply is normal, the energy storage frequency conversion device further detects the AC side output power of the energy storage frequency conversion device; Step S3, if the output power of the AC side does not reach the rated value, the energy storage frequency conversion device enters a charging state, and if the power output of the AC side is not less than the rated power of the energy storage frequency conversion device, charging stops; Step S4, during the charging process, the energy storage frequency conversion device monitors the battery power status in real time. When the battery power reaches 90%, charging stops, but the energy storage frequency conversion device continues to detect the battery power. Once the battery power status is lower than 85%, charging starts again.

9. A discharge control method for an energy storage frequency conversion device, applied to an energy storage frequency conversion device according to any one of claims 1 to 7, comprising the following steps: Step Z1, pre-setting a battery discharge lower limit (taking 10% as an example) in the energy storage frequency conversion device, and the energy storage frequency conversion device continuously detects a power failure state of the power supply system; Step Z2, when it is detected that the power supply system loses power, the energy storage frequency conversion device immediately detects the battery power. If the battery power is greater than 10%, the energy storage frequency conversion device enters a discharge working state; Step Z3, during the discharge process, the energy storage frequency conversion device continuously monitors the battery power, and when it is detected that the battery power is less than 10%, the battery discharge ends; Step Z4, after the battery discharge is completed, the energy storage frequency conversion device enters the standby mode, waiting for the power supply system to resume power supply or other subsequent operation instructions.

10. An energy storage frequency conversion device is applied to a scenario where a load motor works in four quadrants, and is applied to an energy storage frequency conversion device as claimed in any one of claims 1 to 7, comprising the following steps: Step Y1, setting the battery power lower limit, battery power upper limit, charging voltage and discharging voltage of the energy storage device; Step Y2: If the bus voltage is greater than the discharge voltage and less than the charge voltage, the battery is in a state of neither charging nor discharging. At this time, the system maintains the current energy balance state and continues to monitor the bus voltage and other related parameters. Step Y3, if the bus voltage is higher than the discharge voltage and the battery power does not exceed the upper limit, the battery enters the charging state and stores the excess power. At the same time, the battery power and bus voltage are continuously monitored to prevent overcharging abnormalities; Step Y4: If the bus voltage is lower than the discharge voltage and the battery power is not lower than the lower power limit, the battery starts to discharge to replenish energy for the system to maintain normal operation of the system. During the discharge process, pay close attention to the battery power to avoid over-discharge. Step Y5: In other cases, the energy storage device is shut down, and it is necessary to optimize the parameters of the working range and the bus charging and discharging voltage parameters according to the actual operating conditions of the load.

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