energy storage system

Abstract

The application relates to an energy storage system, comprising an energy storage unit and a load power supply connected with a bidirectional conversion unit; the bidirectional conversion unit comprises a processor and a power supply module, the energy storage unit is connected with the power supply module through an energy storage unit side switch, the load power supply is connected with the power supply module through a load power supply side switch, and the processor is used for controlling the energy storage unit side switch to be closed so that the energy storage unit supplies power to the power supply module or controlling the load power supply side switch to be closed so that the load power supply supplies power to the power supply module. Through the application, the dual-power supply design of the power supply module is provided, power supply can be switched through the control of the dual-power supply, energy loss in the process of energy conversion is reduced, and the problem of low energy conversion efficiency of the energy storage system is solved.

Description

Technical Field

[0001] This application relates to the field of energy storage management technology, and in particular to an energy storage system. Background Technology

[0002] An energy storage system is a technological device capable of storing energy and releasing it when needed. It generally includes an energy storage unit, a bidirectional conversion unit, and a load. The bidirectional conversion unit is used to convert electrical energy between the energy storage unit and the load, enabling the energy storage unit to discharge to the load or the load to charge the energy storage unit. In addition to converting electrical energy, the bidirectional conversion unit also provides auxiliary power to the energy storage system to support its energy conversion operations. In existing technologies, the auxiliary power is supplied by the load power source. Because the load power source voltage is much higher than the auxiliary power source voltage, there is a significant energy efficiency loss during the conversion process, thus reducing the overall energy conversion efficiency of the energy storage system.

[0003] There is currently no effective solution to the problem of low energy conversion efficiency in energy storage systems in related technologies. Utility Model Content

[0004] Therefore, it is necessary to provide an energy storage system that can improve energy conversion efficiency to address the aforementioned technical problems.

[0005] In a first aspect, this embodiment provides an energy storage system, including: an energy storage unit connected to a bidirectional conversion unit and a load power supply; the bidirectional conversion unit includes:

[0006] The processor and the power supply module are provided. An energy storage unit-side switch is connected between the energy storage unit and the power supply module. A load power supply-side switch is connected between the load power supply and the power supply module. The processor is used to control the closing of the energy storage unit-side switch so that the energy storage unit supplies power to the power supply module, or to control the closing of the load power supply-side switch so that the load power supply supplies power to the power supply module.

[0007] In some embodiments, the bidirectional conversion unit further includes a current detection module for detecting the load current between the bidirectional conversion unit and the load power supply and sending it to the processor;

[0008] The processor is configured to control the energy storage unit side switch to close and the load power supply side switch to open when the load current is lower than a first threshold, so that the energy storage unit supplies power to the power supply module; and to control the load power supply side switch to close and the energy storage unit side switch to open when the load current is higher than a second threshold, so that the load power supply supplies power to the power supply module.

[0009] In some embodiments, the energy storage system further includes a first power management module for monitoring the power of the energy storage unit and sending it to the processor;

[0010] The processor is also configured to, when the power level is below a third threshold, control the load power supply side switch to close and the energy storage unit side switch to open, so that the load power supply provides power to the power supply module; and when the power level is above a fourth threshold, control the energy storage unit side switch to close and the load power supply side switch to open, so that the energy storage unit provides power to the power supply module.

[0011] In some embodiments, it is applied to an elevator; the energy storage system further includes a voltage detection module for monitoring the bus voltage of the load power supply and sending it to the processor;

[0012] The bidirectional conversion unit further includes a converter; the processor is also configured to control the converter to drive the load power supply to charge the energy storage unit when the change value of the bus voltage is greater than a preset charging threshold, and to control the converter to drive the energy storage unit to discharge the load power supply when the change value of the bus voltage is less than a preset discharging threshold.

[0013] In some embodiments, the processor includes a PID control module that outputs a PWM signal to adjust the switching frequency of the converter.

[0014] In some embodiments, the PID control module has a first PID parameter and a second PID parameter preset, wherein the frequency of the PWM signal adjusted by the first PID parameter is less than the frequency of the PWM signal adjusted by the second PID parameter.

[0015] The processor is further configured to, when the load current is below the first threshold, control the PID control module to adjust the switching frequency of the converter with the first PID parameter; and when the load current is above the second threshold, control the PID control module to adjust the switching frequency of the converter with the second PID parameter.

[0016] In some embodiments, the voltage detection module is also used to wake up the processor from its dormant state when it detects that the change in the bus voltage is greater than a fluctuation threshold.

[0017] In some embodiments, the voltage detection module includes a subprocessor;

[0018] The subprocessor is woken up by an interrupt signal.

[0019] In some embodiments, when the processor enters a sleep state, it drives the energy storage unit side switch to close and the load power supply side switch to open, so that the energy storage unit supplies power to the power supply module.

[0020] In some embodiments, the energy storage system further includes a second power management module and a remote monitoring module, wherein the second power management module is used to monitor the operating status of the energy storage unit;

[0021] The remote monitoring module is connected to the second power management module, the current detection module, the voltage detection module and the elevator for monitoring the working status of the energy storage unit, the load current, the bus voltage and the elevator operating status.

[0022] Compared with related technologies, the energy storage system provided in this embodiment includes: an energy storage unit and a load power supply connected to a bidirectional conversion unit; the bidirectional conversion unit includes: a processor and a power supply module; an energy storage unit-side switch is connected between the energy storage unit and the power supply module, and a load power supply-side switch is connected between the load power supply and the power supply module; the processor is used to control the closing of the energy storage unit-side switch so that the energy storage unit supplies power to the power supply module, or to control the closing of the load power supply-side switch so that the load power supply supplies power to the power supply module. This embodiment provides a dual-power supply design for the power supply module, which can reduce energy efficiency loss during the energy conversion process by controlling the switching between the two power supplies, thus solving the problem of low energy conversion efficiency in energy storage systems.

[0023] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0024] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0025] Figure 1 This is a schematic diagram of the energy storage system in one embodiment;

[0026] Figure 2 This is a schematic diagram of the energy storage system in another embodiment. Detailed Implementation

[0027] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0028] Unless otherwise defined, the technical or scientific terms used in this application shall have the general meaning as understood by one of ordinary skill in the art to which this application pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these,” used in this application, do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to such processes, methods, products, or devices. The terms “connected,” “linked,” and “coupled,” used in this application, are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. The term “multiple” used in this application refers to two or more. The "and / or" operator describes the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: A alone, A and B simultaneously, and B alone. Typically, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," and "third," etc., used in this application are merely for distinguishing similar objects and do not represent a specific ordering of the objects.

[0029] This embodiment provides a schematic diagram of an energy storage system, such as... Figure 1 As shown, the energy storage system includes: an energy storage unit connected to the bidirectional conversion unit and a load power supply;

[0030] The bidirectional conversion unit includes a processor and a power supply module. An energy storage unit-side switch is connected between the energy storage unit and the power supply module, and a load power supply-side switch is connected between the load power supply and the power supply module. The processor is used to control the closing of the energy storage unit-side switch so that the energy storage unit supplies power to the power supply module, or to control the closing of the load power supply-side switch so that the load power supply supplies power to the power supply module.

[0031] Specifically, energy storage units include energy storage media such as capacitors or batteries. An energy storage system is a technological device capable of storing energy and releasing it when needed. A bidirectional conversion unit is used to convert electrical energy between the energy storage unit and the load power source, enabling the energy storage unit to discharge to the load power source or the load power source to charge the energy storage unit. A power supply module provides power to the energy storage system, specifically an auxiliary power source, to provide power for energy conversion control operations. This includes providing low voltage (e.g., 3.3V, 5V, 12V) to control chips (such as PWM controllers, MCUs), drive chips, sensors, and communication modules.

[0032] An energy storage unit-side switch connects the energy storage unit to the power supply module, and a load power supply-side switch connects the load power supply to the power supply module. These switches can be relays or diode circuits, ensuring smooth switching between the two power supplies and preventing system instability due to voltage fluctuations. Furthermore, to ensure voltage stability during switching, a voltage soft-start mechanism is designed to reduce voltage surges during switching and guarantee the continuity and safety of the energy storage system.

[0033] The processor controls the closing of the switch on the energy storage unit side to enable the energy storage unit to supply power to the power supply module, or controls the closing of the switch on the load power supply side to enable the load power supply to supply power to the power supply module, thereby realizing a dual-power supply design for the power supply module. The specific power supply mode of the power supply module can be dynamically switched by the processor according to factors such as load conditions and energy storage unit capacity, in order to reduce the voltage drop from high voltage to low voltage during conversion and improve energy efficiency while ensuring driving capability.

[0034] This embodiment provides a dual-power supply design for the power supply module, and the processor controls the switching of the dual power supply modes. Compared with the existing technology where the auxiliary power supply is powered by the load power supply, resulting in significant energy efficiency loss, this embodiment can dynamically switch the power supply mode according to the actual situation, thereby reducing energy efficiency loss during the conversion process and improving the energy conversion efficiency of the energy storage system.

[0035] In some embodiments, the bidirectional conversion unit further includes a current detection module for detecting the load current between the bidirectional conversion unit and the load power supply and sending it to the processor;

[0036] The processor controls the energy storage unit side switch to close and the load power supply side switch to open when the load current is below a first threshold, so that the energy storage unit supplies power to the power supply module; and controls the load power supply side switch to close and the energy storage unit side switch to open when the load current is above a second threshold, so that the load power supply supplies power to the power supply module.

[0037] Specifically, the current detection module in the bidirectional conversion unit can be a current sensor used to detect the load current between the bidirectional conversion unit and the load power supply. The load current reflects the load status of the energy storage system. After receiving the load current, the processor performs dual-power supply switching based on the load status reflected by the load current. When the load current is lower than a first threshold, it indicates that the current load is low. Therefore, the processor controls the energy storage unit-side switch to close and the load power supply-side switch to open, allowing the energy storage unit to supply power to the power supply module. Under low load conditions, the energy storage unit drives the module with a low voltage, improving conversion efficiency while ensuring driving capability. When the load current is higher than a second threshold, it indicates that the current load is high. Therefore, the processor controls the load power supply-side switch to close and the energy storage unit-side switch to open, allowing the load power supply to supply power to the power supply module. Under high load conditions, the load power supply drives the module with a high voltage, thus ensuring driving capability. The first and second thresholds can be preset and stored.

[0038] Specifically, the first threshold and the second threshold can be determined based on the rated load current. For example, 50% of the rated load current can be set as the first threshold and 60% of the rated load current can be set as the second threshold.

[0039] In this embodiment, the processor can switch between dual power supplies for the power supply module according to the load current. Under low load, it switches to the energy storage unit to supply power to the power supply module, and under high load, it switches to the load power supply to supply power to the power supply module, which can improve energy conversion efficiency while ensuring driving capability.

[0040] In some embodiments, the energy storage system further includes a first power management module for monitoring the power of the energy storage unit and sending the data to the processor; the processor is also configured to control the load power supply side switch to close and the energy storage unit side switch to open when the power is below a third threshold, so that the load power supply provides power to the power supply module; and to control the energy storage unit side switch to close and the load power supply side switch to open when the power is above a fourth threshold, so that the energy storage unit provides power to the power supply module.

[0041] Specifically, after receiving the power from the energy storage unit, the processor performs dual-power switching based on the power level. When the power level falls below a third threshold, it indicates insufficient power. Therefore, the processor controls the load power supply side switch to close and the energy storage unit side switch to open, allowing the load power supply to power the power module and ensuring its normal operation, thus preventing disruption to the energy storage system. When the power level exceeds a fourth threshold, it indicates sufficient power from the energy storage unit. Therefore, the processor controls the energy storage unit side switch to close and the load power supply side switch to open, allowing the energy storage unit to power the power module and reducing power consumption.

[0042] The first power management module can estimate the energy storage unit's capacity by measuring the terminal voltage or by calculating the energy storage unit's capacity using the current integration method; there are no specific restrictions. The third and fourth thresholds can be preset and stored.

[0043] Specifically, the third and fourth thresholds can be determined based on the percentage of remaining battery power. For example, the third threshold can be set to 30% of the remaining battery power, and the fourth threshold can be set to 40% of the remaining battery power.

[0044] In this embodiment, the processor can switch between dual power supplies for the power supply module based on the power level of the energy storage unit. When the power is sufficient, it switches to the energy storage unit to supply power to the power supply module, and when the power is insufficient, it switches to the load power supply to supply power to the power supply module. This can reduce power consumption while ensuring the normal operation of the energy storage system.

[0045] In some embodiments, the energy storage system described above is applied to an elevator; the energy storage system further includes a voltage detection module for monitoring the bus voltage of the load power supply and sending it to the processor; the bidirectional conversion unit further includes a converter; the processor is also used to control the converter to drive the load power supply to charge the energy storage unit when the change value of the bus voltage is greater than a preset charging threshold, and to control the converter to drive the energy storage unit to discharge to the load power supply when the change value of the bus voltage is less than a preset discharging threshold.

[0046] Specifically, the voltage detection module employs a high-precision voltage detection circuit to monitor the bus voltage of the load power supply in real time and further obtain the bus voltage variation. The bus voltage variation can be defined as the fluctuation amplitude and / or fluctuation intensity. The fluctuation amplitude is determined by the peak-to-peak difference between the peak and trough values ​​in the bus voltage sampling, directly reflecting the voltage changes of the elevator energy storage system during operation, especially the significant fluctuations during elevator braking. The fluctuation intensity is determined by the average bus voltage, reflecting the sustained intensity of voltage fluctuations and suitable for capturing the elevator's power demand during operation. For example, the bus voltage fluctuation amplitude can be calculated using time-domain analysis, and the bus voltage fluctuation intensity can be calculated using the RMS (Root Mean Square) method.

[0047] The converter is connected to the processor. After the processor obtains the bus voltage change value monitored, it can use a hysteresis control mechanism to control the converter to switch the charging and discharging state in the main circuit, so as to avoid the energy storage system from frequently switching the charging and discharging state due to small fluctuations.

[0048] Taking the change value as the fluctuation intensity or fluctuation amplitude as an example, corresponding discharge thresholds and charging thresholds are preset for different changes in the bus voltage. When the change value of the bus voltage is greater than the preset charging threshold, the converter is controlled to drive the load power supply to charge the energy storage unit. When the change value of the bus voltage is less than the preset discharge threshold, the converter is controlled to drive the energy storage unit to discharge to the load power supply.

[0049] Furthermore, when the change values ​​are fluctuation amplitude and fluctuation intensity, the discharge threshold includes a first discharge threshold for fluctuation amplitude and a second discharge threshold for fluctuation intensity, and the charging threshold includes a first charging threshold for fluctuation amplitude and a second charging threshold for fluctuation intensity.

[0050] When the fluctuation amplitude is greater than the set first charging threshold (e.g., 30V), and when the fluctuation intensity is greater than the set second charging threshold (e.g., 600V), the control converter drives the load power supply to charge the energy storage unit.

[0051] When the fluctuation amplitude is less than the set first discharge threshold (e.g., 15V) and when the fluctuation intensity is less than the set second discharge threshold (e.g., 505V), the control converter drives the energy storage unit to discharge to the load power supply.

[0052] By monitoring the bus voltage and its changes in this embodiment, and combining this with a hysteresis control mechanism, it is ensured that the changes in the bus voltage will not trigger the switching of the energy storage unit's charging and discharging modes when they are within a certain range. This improves the energy efficiency and stability of the energy storage system, while also enabling elevator power supply and energy recovery, reducing dependence on mains power and saving energy.

[0053] In some embodiments, the processor includes a PID control module that outputs a PWM signal to adjust the switching frequency of the converter.

[0054] Specifically, the processor outputs a PWM (Pulse Width Modulation) signal based on the monitored bus voltage and target voltage of the load power supply, dynamically adjusting the switching frequency of the converter. The target voltage is the desired reference voltage value, which varies in different operating modes. The target voltage is compared with the bus voltage to determine the voltage difference, generating an error signal. This error signal is then used by a PID (Proportional-Integral-Derivative) controller to adjust the frequency of the output PWM signal, thereby regulating the switching frequency of the converter.

[0055] The following is the PID control formula:

[0056] u(t)=Kp*e(t)+Ki*∫e(t)dt+Kd*de(t) / dt;

[0057] Where u(t) is the control output signal of the PID controller, used to adjust the PWM frequency; e(t) is the voltage difference between the bus voltage and the target voltage; and Kp, Ki, and Kd are the proportional, integral, and derivative gains of the PID controller, respectively.

[0058] The PID control module adjusts the PWM frequency based on the real-time voltage difference. When the voltage difference is large, the control module increases the PWM frequency to improve voltage feedback efficiency; when the voltage difference is small, it decreases the PWM frequency to reduce the converter's switching losses and energy consumption. Furthermore, the parameters of the PID control module can be optimized by testing its performance under different voltage fluctuations and load conditions to ensure optimal energy efficiency under various operating conditions.

[0059] In this embodiment, the switching frequency of the converter is adjusted by regulating the PWM frequency according to the voltage difference, which can optimize power feedback and conversion efficiency.

[0060] In some embodiments, the PID control module has a preset first PID parameter and a second PID parameter, wherein the frequency of the PWM signal adjusted by the first PID parameter is less than the frequency of the PWM signal adjusted by the second PID parameter; the processor is also used to control the PID control module to adjust the switching frequency of the converter with the first PID parameter when the load current is lower than a first threshold, and to control the PID control module to adjust the switching frequency of the converter with the second PID parameter when the load current is higher than a second threshold.

[0061] Specifically, the load current is detected by the current detection module in the bidirectional conversion unit, which can reflect the load status of the energy storage system. When the load current is lower than the first threshold, it indicates that the current load is low, and the control PID module adjusts the switching frequency of the converter with a smaller first PID parameter; when the load current is higher than the second threshold, it indicates that the current load is high, and the control PID module adjusts the switching frequency of the converter with a larger second PID parameter.

[0062] By adjusting the converter switching frequency according to the load current in this embodiment, a lower switching frequency can be used under low load and a higher switching frequency can be used under high load, thereby reducing the overall power consumption of the energy storage system.

[0063] In some embodiments, the voltage detection module is also used to wake up the processor in a dormant state when it detects that the change in the bus voltage is greater than the fluctuation threshold.

[0064] Specifically, the change in bus voltage can be the fluctuation amplitude and / or fluctuation intensity, with corresponding fluctuation thresholds pre-set for different bus voltage change values. The processor has a sleep state, and the specific trigger mechanism for entering the sleep state can be set according to specific circumstances. For example, when the system enters standby mode, the processor automatically enters the sleep state, or the conditions for entering the sleep state are set according to the load conditions. Simultaneously with the processor entering the sleep state, the switch on the energy storage unit side closes, and the switch on the load power supply side opens, so that the energy storage unit supplies power to the power supply module, reducing standby power consumption. When the fluctuation amplitude or fluctuation intensity exceeds the corresponding fluctuation threshold, or when both the fluctuation amplitude and fluctuation intensity exceed the corresponding fluctuation threshold, the voltage detection module wakes up the processor to enter normal operating state.

[0065] For example, the fluctuation threshold range of the bus voltage fluctuation amplitude is set to ±10V to ±20V.

[0066] Furthermore, the voltage detection module includes a subprocessor, which can trigger a wake-up mechanism by sending an interrupt signal to the processor. Upon receiving the interrupt signal, the processor immediately exits the sleep state and enters the normal working state.

[0067] In this embodiment, by enabling the processor to enter a sleep state when the change in bus voltage is less than the fluctuation threshold, standby power consumption can be reduced. Simultaneously, in standby mode, the energy storage unit supplies power to the power supply module, improving energy efficiency and further optimizing the energy consumption of the energy storage system. Furthermore, using an interrupt signal to wake up the processor ensures a rapid response and entry into normal operating mode, meeting the real-time requirements of elevator scenarios.

[0068] In some embodiments, the energy storage system further includes a second power management module and a remote monitoring module. The second power management module is used to monitor the operating status of the energy storage unit. The remote monitoring module is communicatively connected to the second power management module, the current detection module, the voltage detection module and the elevator, and is used to monitor the operating status of the energy storage unit, the load current, the bus voltage and the elevator operating status.

[0069] Specifically, the second power management module monitors the operating status of the energy storage unit, including its charging / discharging status, voltage, current, and temperature. The elevator's operating status includes the power supply status of the energy storage unit or load, its position, speed, and door status. The remote monitoring module integrates an IoT platform to monitor the energy storage unit's operating status, load current, bus voltage, and elevator operating status in real time. Based on data analysis, it predicts fault risks and provides early warnings, ensuring the stability and safety of the energy storage system and elevator during operation.

[0070] The present embodiment will now be described and illustrated through preferred embodiments.

[0071] like Figure 2 As shown, the energy storage system provided in this embodiment includes: an energy storage unit (capacitor), a converter, an elevator bus, a frequency converter, a processor, a power supply module, an elevator motor, a current detection module, a voltage detection module, a first power management module, a second power management module (not shown in the figure), and a remote monitoring module (not shown in the figure). In this embodiment, the energy storage system is applied to an elevator, that is, the load power supply is the elevator bus, which is located in the frequency converter. The DC-DC main circuit, i.e., the bidirectional conversion unit, is connected to the elevator bus in the frequency converter. The frequency converter is connected to the elevator motor. The frequency converter receives instructions from the processor and converts the DC power provided by the DC-DC main circuit into AC power with variable frequency and variable voltage to drive the elevator motor. The elevator motor controls the acceleration, constant speed, deceleration, and leveling of the elevator car according to the output signal of the frequency converter. When the elevator is in power-consuming mode, such as when it is fully loaded going upwards or unloaded going downwards, the elevator motor is in motor mode and can be powered by the energy storage unit or the mains power. The power from the energy storage unit and the mains power is transferred to the elevator through the frequency converter bus. The energy storage unit efficiently recovers electrical energy when the elevator operates in various power generation modes, such as braking, unloaded upward movement, and fully loaded downward movement. The elevator motor switches to generator mode, and the generated regenerative energy is fed back to the energy storage unit and the elevator bus via a frequency converter and converter, completing energy recovery. The DC-DC main circuit controls the charging and discharging switching between the energy storage unit and the elevator bus, enabling elevator power supply and energy recovery, reducing dependence on mains power and saving energy. The converter, located in the DC-DC main circuit, connects to the energy storage unit, the elevator bus, the processor, and the power supply module, and works in conjunction with the processor to achieve bidirectional power conversion, switching the charging and discharging states of the energy storage system and the elevator bus.

[0072] Specifically, the processor, based on the bus voltage and its changes monitored by the voltage monitoring module, employs a hysteresis control mechanism to control the converter to drive the elevator bus to charge the energy storage unit, or to control the converter to drive the energy storage unit to discharge to the elevator bus. Furthermore, it adjusts the PWM frequency based on the voltage difference between the bus voltage and the target voltage to regulate the converter's switching frequency.

[0073] An energy storage unit-side switch connects the energy storage unit to the power supply module, and a load power supply-side switch connects the load power supply to the power supply module. Both the energy storage unit-side and load power supply-side switches can be relays or diode circuits. The processor, based on the load current detected by the current detection module and the energy level of the energy storage unit monitored by the first power management module, controls the energy storage unit-side switch to close, enabling the energy storage unit to supply power to the power supply module; or it controls the load power supply-side switch to close, enabling the load power supply to supply power to the power supply module. This achieves dual-power switching, reduces energy efficiency losses during the conversion process, and improves the energy conversion efficiency of the energy storage system.

[0074] Furthermore, when the change in bus voltage is less than the fluctuation threshold, the processor enters a sleep state, drives the energy storage unit side switch to close, and the load power supply side switch to open, so that the energy storage unit supplies power to the power supply module; the voltage detection module is also used to wake up the processor to enter normal working state when it detects that the change in bus voltage is greater than the fluctuation threshold, thereby reducing standby power consumption. At the same time, the energy storage unit supplies power to the power supply module in standby mode, which can improve energy efficiency and further optimize the energy consumption of the energy storage system.

[0075] The power management module employs a high-precision voltage detection circuit to monitor the voltage of the energy storage unit in real time. The processor estimates the remaining power capacity based on the voltage and a preset discharge curve stored in the memory. The power management module is connected to the processor, and the memory stores multiple power levels. The processor adjusts the frequency and duty cycle of the PWM signal according to the estimated remaining power level to drive the converter and regulate the discharge power of the energy storage unit. This allows the voltage of the energy storage unit to gradually, efficiently, and safely decrease to the safe voltage threshold.

[0076] The second power management module is used to monitor the working status of the energy storage unit; the remote monitoring module is connected to the second power management module, the current detection module, the voltage detection module and the elevator to monitor the working status of the energy storage unit, the load current, the bus voltage and the elevator operating status.

[0077] It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. All other embodiments derived by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0078] Obviously, the accompanying drawings are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar situations based on these drawings without any creative effort. Furthermore, it is understood that although the work done in this development process may be complex and lengthy, for those skilled in the art, certain design, manufacturing, or production modifications made based on the technical content disclosed in this application are merely conventional technical means and should not be considered as insufficient disclosure of this application.

[0079] The term "embodiment" in this application refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily imply the same embodiment, nor does it imply that it is mutually exclusive with or alternative to other embodiments. It will be clearly or implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0080] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. An energy storage system, comprising: An energy storage unit and a load power supply connected to a bidirectional conversion unit; characterized in that the bidirectional conversion unit comprises: The system includes a processor, a power supply module, and a current detection module. An energy storage unit-side switch is connected between the energy storage unit and the power supply module, and a load power supply-side switch is connected between the load power supply and the power supply module. The processor is used to control the closing of the energy storage unit-side switch so that the energy storage unit supplies power to the power supply module, or to control the closing of the load power supply-side switch so that the load power supply supplies power to the power supply module. The current detection module is used to detect the load current between the bidirectional conversion unit and the load power supply and send it to the processor; The processor is further configured to, when the load current is lower than a first threshold, control the energy storage unit side switch to close and the load power supply side switch to open, so that the energy storage unit supplies power to the power supply module; and when the load current is higher than a second threshold, control the load power supply side switch to close and the energy storage unit side switch to open, so that the load power supply supplies power to the power supply module.

2. The energy storage system according to claim 1, characterized in that, The energy storage system also includes a first power management module for monitoring the power of the energy storage unit and sending it to the processor; The processor is also configured to, when the power level is below a third threshold, control the load power supply side switch to close and the energy storage unit side switch to open, so that the load power supply provides power to the power supply module; and when the power level is above a fourth threshold, control the energy storage unit side switch to close and the load power supply side switch to open, so that the energy storage unit provides power to the power supply module.

3. The energy storage system according to claim 1, characterized in that, The system is applied to elevators; the energy storage system also includes a voltage detection module for monitoring the bus voltage of the load power supply and sending it to the processor. The bidirectional conversion unit further includes a converter; the processor is also configured to control the converter to drive the load power supply to charge the energy storage unit when the change value of the bus voltage is greater than a preset charging threshold, and to control the converter to drive the energy storage unit to discharge the load power supply when the change value of the bus voltage is less than a preset discharging threshold.

4. The energy storage system according to claim 3, characterized in that, The processor includes a PID control module, which outputs a PWM signal to adjust the switching frequency of the converter.

5. The energy storage system according to claim 4, characterized in that, The PID control module has a first PID parameter and a second PID parameter preset, wherein the frequency of the PWM signal adjusted by the first PID parameter is less than the frequency of the PWM signal adjusted by the second PID parameter. The processor is further configured to, when the load current is below the first threshold, control the PID control module to adjust the switching frequency of the converter with the first PID parameter; and when the load current is above the second threshold, control the PID control module to adjust the switching frequency of the converter with the second PID parameter.

6. The energy storage system according to claim 3, characterized in that, The voltage detection module is also used to wake up the processor from its dormant state when it detects that the change in the bus voltage is greater than the fluctuation threshold.

7. The energy storage system according to claim 6, characterized in that, The voltage detection module includes a subprocessor; The subprocessor is woken up by an interrupt signal.

8. The energy storage system according to claim 6, characterized in that, When the processor enters a sleep state, it drives the energy storage unit side switch to close and the load power supply side switch to open, so that the energy storage unit supplies power to the power supply module.

9. The energy storage system according to claim 3, characterized in that, The energy storage system also includes a second power management module and a remote monitoring module, wherein the second power management module is used to monitor the working status of the energy storage unit; The remote monitoring module is connected to the second power management module, the current detection module, the voltage detection module and the elevator for monitoring the working status of the energy storage unit, the load current, the bus voltage and the elevator operating status.

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