Energy storage control device, method, and system

Abstract

The application relates to an energy storage control device, method and system. The energy storage control device comprises a battery energy storage module including a battery unit and a management unit; a power interface module connected with the battery energy storage module, used for connecting with a direct-current bus of a variable frequency module, and used for adjusting the size of the charge-discharge current of the battery unit according to a received current control signal; a braking module connected with the power interface module, used for connecting with the direct-current bus of the variable frequency module, and used for consuming overflow power according to a received braking control signal; an acquisition module used for connecting with the direct-current bus of the variable frequency module, and used for acquiring a bus monitoring signal; and a control module used for acquiring regenerative power and allowed charging power according to a battery state signal and the bus monitoring signal, outputting a current control signal according to the battery state signal, and outputting a braking control signal in the case that the regenerative power exceeds the allowed charging power. The device can reduce energy waste.

Description

Technical Field

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

[0002] In related technologies, elevators are powered by mains electricity. When the mains power fails, the elevator cannot operate stably for extended periods, disrupting daily work and life. Furthermore, regenerative energy is generated when the elevator drives the main circuit. The current technology handles this regenerative energy by consuming resistors, resulting in significant energy waste. Summary of the Invention

[0003] Therefore, it is necessary to provide an energy storage control device, method, and system that can reduce energy waste in response to the above-mentioned technical problems.

[0004] In a first aspect, this application provides an energy storage control device, comprising:

[0005] A battery energy storage module includes a battery cell and a management unit, wherein the management unit is used to acquire the battery status signal of the battery cell;

[0006] A power interface module is connected to the battery energy storage module and is used to connect to the DC bus of the frequency converter module, and to adjust the charging and discharging current of the battery cell according to the received current control signal.

[0007] A braking module, connected to the power interface module, is used to connect to the DC bus of the frequency converter module and to consume overflow power according to the received braking control signal; the overflow power is related to the regenerative power and the allowable charging power.

[0008] The acquisition module is used to connect to the DC bus of the frequency converter module and to acquire bus monitoring signals;

[0009] The control module is connected to the power interface module, the battery energy storage module, the acquisition module, and the braking module, respectively. It is used to obtain the regenerative power and the allowable charging power according to the battery status signal and the bus monitoring signal, output the current control signal according to the battery status signal, and output the braking control signal when the regenerative power exceeds the allowable charging power.

[0010] In one embodiment, the power interface module includes:

[0011] A bidirectional conversion unit is connected to the battery energy storage module and the control module respectively, and is used to connect to the DC bus of the frequency converter module;

[0012] The control module is further configured to control the bidirectional conversion unit to be in a first conversion mode when the regeneration power is less than a preset power threshold, and to control the bidirectional conversion unit to be in a second conversion mode when the regeneration power is greater than the preset power threshold.

[0013] In the first conversion mode, the battery energy storage module discharges to the frequency converter module; in the second conversion mode, the frequency converter module discharges to the battery energy storage module.

[0014] In one embodiment, the bidirectional conversion unit includes an energy storage inductor; the battery status signal includes a battery total voltage signal;

[0015] The control module is also used to determine the duty cycle of the current control signal based on the reference current signal, the current signal on the energy storage inductor, and preset control parameters.

[0016] The reference current signal is related to the allowable charging power and the total battery voltage signal.

[0017] In one embodiment, the power interface module includes:

[0018] The current limiting unit is connected to the battery unit and the control module respectively, and is used to connect to the DC bus of the frequency converter module;

[0019] The control module is further configured to determine the duty cycle of the current control signal based on the charging and discharging current, a preset reference charging and discharging current signal, and preset control parameters when the regeneration power exceeds the allowable charging power.

[0020] In one embodiment, the braking module includes a braking resistor;

[0021] The control module is further configured to determine the bus voltage of the DC bus based on the bus monitoring signal; the control module is further configured to determine the duty cycle of the braking control signal based on the overflow power, the resistance value of the braking resistor and the bus voltage when the regenerative power exceeds the allowable charging power.

[0022] In one embodiment, the braking module includes:

[0023] A braking resistor, the first end of which is used to connect to the first DC bus of the frequency converter module;

[0024] A switching device, wherein a first terminal of the switching device is connected to a second terminal of the braking resistor, the second terminal of the switching device is used to connect to a second DC bus of the frequency converter module, and a control terminal of the switching device is used to receive the braking control signal;

[0025] The switching device is used to adjust the equivalent input power of the braking resistor according to the braking control signal.

[0026] In one embodiment, the braking module further includes:

[0027] A buffer circuit is provided, wherein a first terminal of the buffer circuit is connected to a first terminal of the switching device, and a second terminal of the buffer circuit is connected to a second terminal of the switching device; the buffer circuit is used to suppress transient voltage spikes between the first and second terminals of the switching device.

[0028] In one embodiment, the device further includes:

[0029] A conversion module, connected to the control module, is used to connect to the DC bus of the frequency converter module and to convert the first voltage signal of the DC bus to provide a power signal to the control module.

[0030] A redundant triggering module is connected to the acquisition module, the conversion module, and the braking module respectively, and is used to output a redundant control signal based on the power supply signal and the bus monitoring signal; the redundant control signal is used to control the braking module to be in a full braking state.

[0031] In one embodiment, the redundancy triggering module includes:

[0032] An operational amplifier is provided, with its first input terminal connected to the acquisition module, its second input terminal connected to the conversion module, and its output terminal connected to the braking module. The operational amplifier is used to output a redundant control signal when the bus monitoring signal is greater than the power supply signal.

[0033] Secondly, this application provides an energy storage control method, applied to the energy storage control device described in any of the above embodiments; the method includes:

[0034] Acquire battery status signals and bus monitoring signals;

[0035] The regeneration power and allowable charging power are obtained based on the battery status signal and the bus monitoring signal;

[0036] Based on the battery status signal and the bus monitoring signal, the current control signal is output to the power interface module;

[0037] If the regeneration power exceeds the allowable charging power, the braking control signal is output to the braking module.

[0038] Thirdly, this application provides an energy storage control system, including a load, a frequency converter connected to the load, and the energy storage control device described in any of the above embodiments.

[0039] The aforementioned energy storage control device, method, and system include a battery energy storage module, a power interface module, a braking module, a data acquisition module, and a control module. By connecting the battery energy storage module to the DC bus of the frequency converter module via the power interface module, and by allowing the control module to adjust the charging and discharging current of the battery cells based on the battery status signal and the bus monitoring signal, bidirectional energy flow between the battery cells and the frequency converter module can be achieved. This allows the regenerative energy generated by the frequency converter module to be recovered and stored in the battery energy storage module instead of being directly consumed through a resistor. It also allows the battery cells to supply power to the frequency converter module, reducing the frequency converter module's consumption of mains power, thereby improving energy utilization efficiency and achieving energy saving. Furthermore, the control module can calculate the regenerative power and allowable charging power based on the battery status signal and the bus monitoring signal. When the regenerative power exceeds the allowable charging power, a braking control signal is output. That is, when the regenerative energy is within the acceptable range of the battery cells, it is preferentially stored; when it exceeds the battery cells' receiving capacity, the excess energy is linearly consumed by the braking module, thus always maintaining the DC bus voltage within a safe range and ensuring the safety of the battery cells and the frequency converter module. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the energy storage control device and frequency converter module in one embodiment;

[0042] Figure 2 This is a schematic diagram of the energy storage control device and frequency converter module in another embodiment;

[0043] Figure 3 This is a schematic diagram of the bidirectional conversion unit in one embodiment;

[0044] Figure 4 This is a schematic diagram of the bidirectional conversion unit in another embodiment;

[0045] Figure 5 This is a schematic diagram of the braking module in one embodiment;

[0046] Figure 6 Another schematic diagram of the bidirectional conversion unit in one embodiment;

[0047] Figure 7 This is a flowchart illustrating an energy storage control method in one embodiment.

[0048] Explanation of reference numerals in the attached drawings: 100-Energy storage control device, 200-Variable frequency module, 10-Battery energy storage module, 20-Power interface module, 21-Bidirectional conversion unit, 22-Current limiting unit, 30-Braking module, 40-Acquisition module, 50-Control module, 60-Conversion module, 70-Redundant trigger module. Detailed Implementation

[0049] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0051] It is understood that the terms “first,” “second,” etc., used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another.

[0052] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0053] It should be noted that when one element is considered to be "connected" to another element, it can be directly connected to the other element or connected to the other element through an intermediary element. Furthermore, in the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if there is transmission of electrical signals or data between the connected objects.

[0054] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0055] In related technologies, elevators are powered by mains electricity. When the mains power fails, the elevator cannot operate stably for extended periods, disrupting daily life and work. Furthermore, regenerative energy is generated when the elevator drives the main circuit. The current technology handles this regenerative energy by consuming resistors, resulting in significant energy waste.

[0056] To reduce energy waste, the relevant technologies mainly involve two energy recovery schemes:

[0057] The first type is a "hard switching" scheme based on voltage thresholds. This involves monitoring the bus voltage and charge level. When the voltage exceeds a set value (e.g., 650V) and the battery cannot absorb the charge, the energy-saving device is directly disconnected and a braking resistor is connected. Its main drawback is that the control logic is discontinuous and mutually exclusive. At the boundary of the battery's charging capacity, the sudden switching of high-power loads is equivalent to a step change in impedance, which can easily cause shocks and oscillations in the DC bus voltage, triggering the inverter's overvoltage protection. Furthermore, this scheme only focuses on the unidirectional recovery of regenerative energy and does not consider the reverse support requirements during heavy elevator starts or grid fluctuations, making it impossible to use energy storage units to stabilize the bus voltage or perform peak shaving and valley filling.

[0058] The second category is passive execution schemes based on PWM modulation. To address the impact of hard switching, related fields have proposed continuous regulation schemes based on PWM. For example, using IGBTs in conjunction with PWM signals to control the on / off state of the braking resistor achieves linear regulation of energy consumption. However, this scheme lacks local collaborative arbitration capabilities and typically acts as a subordinate execution mechanism heavily reliant on upper-level instructions. When dealing with dynamic current limiting of the battery or millisecond-level power surges, communication and processing delays often lead to bus voltage overshoot. Furthermore, this scheme focuses on single energy consumption control and lacks a low-level overall coordination mechanism for both energy storage and energy consumption channels, making it difficult to achieve seamless switching between recovery overflow and drive deficit.

[0059] In summary, the energy recovery schemes in related technologies either lack linear regulation capabilities, leading to bus oscillations, or, as passive units, lack the ability to arbitrate bidirectional power flows. Therefore, there is an urgent need for a control system that can integrate BMS state feedforward, directly arbitrate power flow within the underlying controller, and synchronously control the power interface unit and braking unit for bidirectional energy throughput.

[0060] To address the aforementioned technical problems, please refer to some exemplary embodiments. Figure 1 This application provides an energy storage control device 100, comprising:

[0061] The battery energy storage module 10 includes a battery cell and a management unit, wherein the management unit is used to acquire the battery status signal of the battery cell;

[0062] The power interface module 20 is connected to the battery energy storage module 10 and is used to connect to the DC bus of the frequency converter module 200, and to adjust the charging and discharging current of the battery cell according to the received current control signal.

[0063] The braking module 30 is connected to the power interface module 20 and is used to connect to the DC bus of the frequency converter module 200. It is also used to consume the overflow power according to the received braking control signal. The overflow power is related to the regenerative power and the allowable charging power.

[0064] The acquisition module 40 is used to connect to the DC bus of the frequency converter module 200 and to acquire bus monitoring signals.

[0065] The control module 50 is connected to the power interface module 20, the battery energy storage module 10, the acquisition module 40 and the braking module 30 respectively. It is used to obtain the regeneration power and the allowable charging power according to the battery status signal and the bus monitoring signal, output the current control signal according to the battery status signal, and output the braking control signal when the regeneration power exceeds the allowable charging power.

[0066] In this embodiment, the frequency converter 200 is connected to a load, such as an elevator, and is used to control the operation of the load. The frequency converter 200 has two power supply methods: the first is to draw power from the mains power, and the second is to draw power from the battery cell. At the same time, the frequency converter 200 can also charge the battery cell in reverse.

[0067] The management unit can be a BMS (Battery Management System). The BMS can monitor key parameters such as voltage, current, and temperature of each cell in the battery cell in real time through a sensor network, and calculate the state of charge (SOC), state of health (SOH), and dynamic maximum allowable charging current I of the battery cell. bat_limit The BMS can be directly connected to the control module 50 via an independent communication bus (such as CAN or RS485) to send the aforementioned battery status signals to the control module 50 in the form of digital messages. In application, the management unit and the battery unit can be integrated or configured independently.

[0068] The power interface module 20 connects the DC bus and the battery cell, serving as the core actuator for bidirectional energy flow. Its control terminal is connected to the drive output interface of the control module 50. Based on the received current control signal, the power interface module 20 finely adjusts the magnitude of the charging or discharging current. To adapt to different matching conditions between the battery cell voltage and the DC bus voltage, the internal electrical topology of the power interface module 20 adopts a reconfigurable design: it can be configured as a bidirectional DC / DC converter structure with a wide range of step-up and step-down capabilities (suitable for voltage mismatch scenarios), or as a smoothing and current-limiting circuit structure based on PWM chopping (suitable for high-voltage direct-connection scenarios), thereby achieving universal compatibility with energy storage solutions of different voltage levels.

[0069] The braking module 30 is connected between the positive and negative terminals of the DC bus. When the regenerative power generated by the DC bus exceeds the receiving capacity of the battery cell, the braking module 30 can respond to the braking control signal output by the control module 50 to accurately consume the overflow power.

[0070] The acquisition module 40 is connected between the positive and negative DC bus of the frequency converter module 200. It is responsible for acquiring the physical and electrical parameters of the DC bus, generating a bus monitoring signal, and sending it to the control module 50. The acquisition module 40 can integrate a high-voltage sampling circuit and a Hall current sensor, configured to monitor the bus voltage V in real time. bus With bus current I bus .

[0071] The control module 50 is the core of the energy storage control device 100, integrating a high-frequency PWM signal generator and a logic processor. It has dual information inputs: one input receives bus V / I data from the acquisition module 40, and the other receives battery capacity boundary data from the BMS via a communication interface. The control module 50 calculates the target control quantity based on its internal power flow arbitration algorithm and directly generates two independent drive signals via its integrated PWM module. The first PWM signal is connected to the power interface module 20, controlling the charging / discharging current by adjusting the duty cycle; the second PWM signal is output to the braking module 30, controlling the equivalent input power of the braking resistor by adjusting the duty cycle. The control module 50 internally runs the power flow arbitration algorithm to calculate the difference between the total regenerative power and the battery absorption capacity, further calculating the overflow power P based on the bus voltage status. excess Based on this, two PWM pulse width modulation signals are generated and output.

[0072] In the application, the BMS can report battery status signals via the communication bus at a fixed period (e.g., 100ms). The control module 50 can perform power calculation and control at a faster period (e.g., 1ms). In the coordinated control of these two different periods, this application adopts a combination of a latest value hold strategy and a heartbeat timeout verification mechanism. Within the 100ms interval between two data updates by the BMS, the control module 50 always calls the valid allowed charging power P of the previous frame stored in the buffer in each 1ms control cycle. bat_limit This serves as the constraint boundary for the current moment. This ensures that the high-frequency control loop always has a clear numerical reference, avoiding calculation oscillations caused by data gaps. Simultaneously, the control module 50 has an internal watchdog timer. If no new message is received from the BMS for more than a set time (e.g., 300ms, i.e., more than 3 frames lost), the system determines that BMS communication has failed and immediately resets the P... bat_limit Forced to zero and control the energy storage management device to enter safe takeover mode, fully activating the braking module 30 to ensure system safety in communication blind spots or failures. Simultaneously, the allowable discharge power P is... bat_dis_limit Forced zeroing prevents the battery cells from outputting power in reverse to the DC bus. In safe takeover mode, the current path between the battery cells and the DC bus is cut off. The battery cells neither receive charging nor discharge externally, and the braking module 30 is in full braking mode to ensure the safety of the bus voltage.

[0073] Within each rapid control cycle (the cycle in which control module 50 performs power calculation and control), control module 50 uses the latest received battery status signal to perform calculations, thereby achieving dynamic tracking and allocation of regenerative power while meeting battery safety boundaries. The specific process is as follows:

[0074] First, the control module 50 calculates the DC bus voltage V based on the bus monitoring signal uploaded by the acquisition module 40. bus With current I bus The regeneration power P was calculated. bus =V bus *I bus Simultaneously read the allowable charging power P reported by the BMS. bat_limit (This value is dynamically generated by the BMS based on SOC, SOH, and cell temperature). Subsequently, control module 50 calculates the power deficit ΔP = P. bat_limit -P bus And define the overflow power P excess =max(0, -ΔP). Where ΔP and P are related. excess The calculation only applies to P. bus Effective under regeneration conditions with a power level of ≥0, the system employs independent discharge power arbitration logic in discharge support mode. In discharge support mode, the battery unit supplies power to the inverter module 200.

[0075] To cover the electric (energy-consuming) operating conditions of electromechanical equipment, this invention further defines the power direction, that is, the direction of the busbar flowing into the battery is set as positive (regenerative), and the direction of the busbar flowing out is set as negative (electric). The control module 50 synchronously reads the allowable discharge current I reported by the BMS. bat_dis_limit With the allowable discharge power P bat_dis_limit When the calculated P bus <0 (i.e., the electromechanical equipment is in an electric state) and |P bus |Exceeding the set threshold or bus voltage V bus When the voltage drops below the support threshold (e.g., 530V), the energy storage control device 100 enters the discharge support mode. At this time, the control module 50 calculates the target support power P. support =min(|P bus |,P bat_dis_limit ), and generate a discharge command.

[0076] In this embodiment, when the regenerative power of the DC bus does not exceed the allowable charging power of the battery cell, the battery cell can receive all the regenerative energy generated by the DC bus. At this time, the control module 50 controls the braking module 30 to not operate, so as to avoid energy waste. At the same time, when the battery cell is in a discharging state, that is, when the battery cell supplies power to the DC bus, the control module 50 also controls the braking module 30 to not operate, so as to avoid wasting the energy stored in the battery cell.

[0077] The aforementioned energy storage control device 100 includes a battery energy storage module 10, a power interface module 20, a braking module 30, a data acquisition module 40, and a control module 50. By connecting the battery energy storage module 10 to the DC bus of the frequency converter module 200 via the power interface module 20, and by adjusting the charging and discharging current of the battery cells according to the battery status signal and the bus monitoring signal, bidirectional energy flow between the battery cells and the frequency converter module 200 can be achieved. This allows the regenerative energy generated by the frequency converter module 200 to be recovered and stored in the battery energy storage module 10 instead of being directly consumed through a resistor. It also allows the battery cells to supply power to the frequency converter module 200, reducing the frequency converter module 200's consumption of mains power, thereby improving energy utilization efficiency and achieving energy saving. Furthermore, the control module 50 can calculate the regeneration power and the allowable charging power based on the battery status signal and the bus monitoring signal. When the regeneration power exceeds the allowable charging power, it outputs a braking control signal. That is, when the regeneration energy is within the acceptable range of the battery cell, it is stored first. When it exceeds the receiving capacity of the battery cell, the excess energy is linearly consumed by the braking module 30, thereby always maintaining the DC bus voltage within a safe range and ensuring the safety of the battery cell and the inverter module 200.

[0078] In some exemplary embodiments, please refer to Figure 2 The power interface module 20 includes:

[0079] The bidirectional conversion unit 21 is connected to the battery energy storage module 10 and the control module 50 respectively, and is used to connect to the DC bus of the frequency converter module 200.

[0080] The control module 50 is also used to control the bidirectional conversion unit 21 to be in a first conversion mode when the regeneration power is less than a preset power threshold, and to control the bidirectional conversion unit 21 to be in a second conversion mode when the regeneration power is greater than the preset power threshold.

[0081] In the first conversion mode, the battery energy storage module 10 discharges to the frequency converter module 200; in the second conversion mode, the frequency converter module 200 discharges to the battery energy storage module 10.

[0082] In applications, the power interface module 20 can be a bidirectional conversion unit 21, i.e., a bidirectional DC-DC circuit. In one example, the circuit structure of the bidirectional conversion unit 21 can be as follows: Figure 3 As shown, from Figure 3As can be seen, the bidirectional conversion unit 21 mainly consists of a half-bridge topology circuit composed of an energy storage inductor L, filter capacitors C1 and C2, diodes D1 and D2, and power switches Q1 and Q2. The bases of power switches Q1 and Q2 are connected to the control module 50, respectively. Power switches Q1 and Q2 control the charging and discharging time of inductor L according to the frequency and duty cycle of the received PWM signal, thereby realizing bidirectional energy flow and voltage matching. For example, Figure 3 In this circuit, U1 represents the voltage between the positive and negative DC bus, and U2 represents the voltage between the positive and negative terminals of the battery cell. When the power switch Q2 remains off, by changing the on-time of the power switch Q1 (i.e., the duty cycle of the power switch Q1), a buck circuit voltage reduction function from U1 to U2 can be achieved, meaning the inverter module 200 discharges to the battery storage module 10. When the power switch Q1 remains off, by changing the on-time of the power switch Q2 (i.e., the duty cycle of the power switch Q2), a boost circuit voltage increase function from U2 to U1 can be achieved, meaning the battery cell discharges to the inverter module 200.

[0083] When the power interface module 20 is a bidirectional conversion unit 21, the energy storage control device 100 of this application includes four operating modes: safe takeover mode, full recovery mode, cooperative braking mode, and discharge support mode.

[0084] When the system malfunctions (BMS error) or the battery is fully charged (SOC≥100%), the energy storage control device 100 enters the safety takeover mode: the control module 50 forcibly locks the bidirectional conversion unit 21 and puts the braking module 30 into full power to ensure the safety of the bus voltage.

[0085] When ΔP≥0 and the BMS is fault-free, the energy storage control device 100 enters the full recovery mode: at this time, when the regeneration power is less than or equal to the allowable charging power P bat_limit If it is determined that the energy can be completely recovered, the control module 50 drives the bidirectional DC-DC converter to enter the second conversion mode, while controlling the braking module 30 to remain silent (i.e., the duty cycle of the signal received by the switching device in the braking module is 0, and the braking module does not consume power).

[0086] When ΔP < 0 and the BMS is fault-free, the energy storage control device 100 enters the cooperative braking mode: at this time, the regeneration power exceeds the allowable charging power P. bat_limit Upon determining energy overflow, control module 50 drives the battery unit at P bat_limit The system operates at constant power while simultaneously controlling the IGBT of the braking module 30 to perform PWM chopping, ensuring its average power consumption equals P. excess This allows for smooth clamping of the bus voltage.

[0087] When Pbus When the voltage is <0 and the BMS allows discharge, the energy storage control device 100 enters the discharge support mode: when the electromechanical equipment starts under heavy load or the bus voltage drops, the control module 50 drives the bidirectional DC-DC converter to enter the Boost discharge state, with P support Current is injected into the DC bus to achieve peak shaving and valley filling and bus voltage stabilization, while keeping the braking unit silent.

[0088] In some exemplary embodiments, such as Figure 3 As shown, the bidirectional conversion unit 21 includes an energy storage inductor L; the battery status signal includes the battery total voltage signal; the control module 50 is also used to determine the duty cycle of the current control signal based on the reference current signal, the current signal on the energy storage inductor and the preset control parameters; wherein, the reference current signal is related to the allowable charging power and the battery total voltage signal.

[0089] The reference current signal includes the charging current command I. bat_limit and discharge current command I bat_dis_limit .

[0090] In the application, when the bidirectional conversion unit 21 is in the second conversion mode, the control module 50 can adjust the charging power P reported by the BMS. bat_limit With battery total voltage signal V bat Calculate the current upper limit reference value I. bat : .

[0091] Meanwhile, when the bus feedback power suddenly increases (e.g., exceeding 30kW instantaneously under heavy load), directly increasing the duty cycle will cause the battery terminal current to rise too quickly. Therefore, in this application, to prevent response overshoot, the final reference current signal (charging current command I) is... bat_limit To avoid overcurrent damage or triggering BMS protection, the following values ​​should be minimized:

[0092]

[0093] Among them, I max_temp To enable dynamic current limiting based on cell temperature, the current rate is automatically reduced at low or high temperatures; For cell temperature; I max_soc The current decay curve is determined by the battery cell's SOC when it is close to full charge, preventing instantaneous overcharging at full charge; I max_hw This refers to the maximum current (e.g., 50A) that the power switch in the bidirectional converter unit 21 can carry in Buck buck mode.

[0094] Next, the reference current signal I bat_limit The actual feedback value I of the inductor current LThe duty cycle D of the current control signal generated by the PI regulator is compared:

[0095]

[0096] Among them, K P K I The actual feedback value of the inductor current I is the preset control parameter. L This information can be obtained through BMS monitoring.

[0097] Similarly, when the bidirectional conversion unit 21 is in the first conversion mode, the control module 50 can adjust the discharge power P reported by the BMS. bat_dis_limit With battery total voltage signal V bat Calculate the current upper limit reference value I of the discharge current. bat : .

[0098] When the battery cell begins to discharge, to prevent a sudden drop in battery voltage that could trigger undervoltage protection and to suppress current overshoot during Boost circuit startup, the final reference current signal (discharge current command I) is determined. bat_dis_limit It also needs to undergo minimum value logic verification:

[0099]

[0100] Among them, I dis_temp To enable dynamic discharge current limiting based on cell temperature, especially at low temperatures where increased internal resistance necessitates automatic and significant derating; I min_soc Determined by the current decay curve when the SOC is close to the discharge threshold, this prevents low-current surges from pulling down the voltage and causing shutdown; I dis_hw This is the maximum current (e.g., 50A) that the power switch in the bidirectional converter unit 21 can carry in Boost mode.

[0101] Next, the reference current signal I bat_dis_limit The actual feedback value I of the inductor current L The duty cycle D of the current control signal generated by the PI regulator is compared:

[0102]

[0103] In one example, the duty cycle D of the current control signal is strictly limited to a safe range (e.g., 0). <D<D max1 D max1 It can be less than or equal to 0.85 to ensure a safety margin and avoid overcurrent.

[0104] In this embodiment, to reduce the size of the energy storage inductor and optimize battery current ripple, the control frequency of the current control signal of the bidirectional converter 21 is typically set relatively high (e.g., 10kHz~20kHz) to utilize high-frequency chopping characteristics to reduce inductor ripple current. Simultaneously, a dead time, such as 150ns, is set to ensure interlocking safety between the upper and lower transistors. This logic ensures that the bidirectional converter 21 operates smoothly in a "constant power absorption" mode throughout the entire feedback process, ensuring that the actual charging power never exceeds P. bat_limit This also avoids bus voltage overshoot and battery cell current overshoot.

[0105] In some exemplary embodiments, please refer to Figure 4 The power interface module 20 includes:

[0106] The current limiting unit 22 is connected to the battery unit and the control module 50 respectively, and is used to connect to the DC bus of the frequency converter module 200;

[0107] The control module 50 is also used to determine the duty cycle of the current control signal based on the charging and discharging current, the preset reference charging and discharging current signal, and the preset control parameters when the regeneration power exceeds the allowable charging power.

[0108] In applications, the power interface module 20 can also be a current limiting unit 22. The current limiting unit 22 is connected in series between the DC bus and the battery cell, and consists of a power semiconductor switching transistor (such as an IGBT or MOSFET) and a DC smoothing reactor L. dc It consists of a current transformer. The current transformer is used to detect the current charging and discharging current I. real In one example, when I real When I is positive, real This is the charging current; when I real When I is negative, real This is the discharge current.

[0109] In this embodiment, the function of the current limiting unit 22 is not to perform voltage transformation, but to use the current inertia of the inductor to suppress current surges di / dt in PWM current limiting chopping mode, smooth the high-frequency pulse current into a continuous DC current, and protect the battery and the switching transistor.

[0110] Unlike the power interface module 20, which actively establishes the output voltage and pumps current by adjusting the duty cycle when it is a bidirectional conversion unit 21, when the power interface module 20 is a current limiting unit 22, the current limiting unit 22 is equivalent to an adjustable "one-way valve." It does not have the ability to actively increase or decrease the voltage; instead, it uses the natural physical voltage difference between the DC bus and the battery cell to drive the current flow. The control module 50 only activates when it detects that the current flowing naturally between the DC bus and the battery cell exceeds the BMS safety boundary (I0). real ≥Ibat_limit or |I real |>I bat_dis_limit When the current is within a safe threshold, it is interrupted; when the current is within a safe range, it remains in a fully conductive state to achieve passive feedback with zero switching losses.

[0111] When the power interface module 20 is the current limiting unit 22, the energy storage control device 100 of this application includes four operating modes: safe takeover mode, natural feedback mode, cooperative current limiting mode and discharge support mode.

[0112] When a system malfunctions (BMS error) or the battery is fully charged (SOC≥100%), the energy storage control device 100 enters the safety takeover mode: the control module 50 forcibly locks the bidirectional conversion unit 21 and puts the braking module 30 into full power to ensure the safety of the bus voltage.

[0113] When the bus voltage V bus Total voltage of the battery cell V bat At this time, the energy storage control device 100 enters the discharge support mode: when the electromechanical equipment is under high energy consumption conditions such as heavy load lifting or acceleration, the DC bus voltage V... bus Below battery voltage V bat At this time, it enters the discharge support state. First, the control module 50 monitors the discharge current I in real time. real If the current is within a safe range (|I real | bat_dis_limit The power switch in the current limiting unit 22 is kept on with a high duty cycle (e.g., D=90%), utilizing the physical voltage difference to achieve low-loss natural discharge and support the bus voltage. When the voltage difference is too large, it causes the discharge current I... real Exceeding the security threshold allowed by the BMS (|I real |>I bat_dis_limit When the current limiting unit 22 exits the fully conductive state, the control module 50 immediately takes over control, switching to PWM chopper control. The duty cycle is adjusted using a PI algorithm to force the discharge current to be clamped at a safe extreme value (e.g., 50A) to prevent battery overcurrent or fuse blowout.

[0114] When I real ≥I bat_limit At this time, the energy storage control device 100 enters the cooperative current limiting mode: the control module 50 adjusts the duty cycle D of the power switch in the current limiting unit 22 through the PI algorithm. During the power switch conduction period, the current rises linearly through the DC smoothing reactor; during the turn-off period, the current freewheels through the freewheeling diode (or synchronous rectifier). The charging current I is then... real Pincers in I bat_limit At this time, the actual power absorbed by the battery side is: ​Because the current limiting unit 22 cuts off part of the current, energy accumulates on the bus side, causing V to... bus As the power increases, the MCU calculates the overflow power in real time. The control module 50 then drives the braking module 30, enabling the braking module 30 to precisely dissipate the overflow power.

[0115] When P bus >0 and the actual value of the charging current is 0. real bat_limit When the energy storage control device 100 enters the natural feedback mode, the battery capacity is sufficient and no intervention is required. It utilizes the physical pressure difference to achieve the most efficient feedback. Therefore, the current limiting unit 22 is kept fully conductive (e.g., D=90%). At this time, the battery cell naturally absorbs energy based on the pressure difference ΔV between the DC bus and the battery cell, while the braking unit remains silent. Where ΔV=V bus -V bat .

[0116] In some exemplary embodiments, the braking module 30 includes a braking resistor; the control module 50 is further configured to determine the bus voltage of the DC bus based on the bus monitoring signal; the control module 50 is further configured to determine the duty cycle of the braking control signal based on the overflow power, the resistance value of the braking resistor and the bus voltage when the regenerative power exceeds the allowable charging power.

[0117] In this embodiment, the main function of the braking module 30 is to dissipate overflow power, and the control module 50 updates the duty cycle D of the braking control signal in each fast control cycle. brake : Among them, P brake For the target power, P brake =P excess R br This is the resistance value of the braking resistor.

[0118] The controller limits the duty cycle in real time (e.g., 0). <D brake <D max2 D max2 It can be less than or equal to 0.9), so that the equivalent input power of the braking resistor linearly follows the change of the overflow power, realizing smooth control of the bus voltage, avoiding voltage oscillation caused by traditional hysteresis comparison control, and ensuring that the instantaneous power absorbed by the braking resistor is exactly equal to the overflow power.

[0119] In some exemplary embodiments, the braking module 30 includes:

[0120] A braking resistor, the first end of which is used to connect to the first DC bus of the frequency converter module 200;

[0121] ​​The switching device has its first terminal connected to the second terminal of the braking resistor, and its second terminal connected to the second DC bus of the frequency converter module 200. The control terminal of the switching device is used to receive the braking control signal. The switching device is used to adjust the equivalent input power of the braking resistor according to the braking control signal.

[0122] A buffer circuit is used to suppress transient voltage spikes between the first and second terminals of the switching device. The first terminal of the buffer circuit is connected to the first terminal of the switching device, and the second terminal of the buffer circuit is connected to the second terminal of the switching device.

[0123] In one example, the circuit structure of the braking module 30 of this application can be found in [reference needed]. Figure 5 Among them, the braking resistor R br The first terminal is connected to the positive DC bus of the frequency converter module 200, and the braking resistor R br The second terminal of the switch is connected to the first terminal of the switching device Q3, and the second terminal of the switching device Q3 is connected to the negative DC bus of the frequency converter module 200. The control terminal of the switching device Q3 is connected to the control module 50. The buffer circuit includes diode D3 and buffer resistor R. sn and buffer capacitor C sn The anode of diode D3 is connected to the buffer resistor R. sn The first terminal of the diode D3 is connected to the first terminal of the switching device Q3, and the cathode of the diode D3 is connected to the buffer resistor R. sn The second terminal, buffer capacitor C sn The first end is connected to the buffer capacitor C. sn The second terminal is connected to the second terminal of the switching device Q3.

[0124] The switching devices in the braking module 30 of this application are controlled by high-frequency PWM. Considering the heat loss limitation of the buffer circuit and the load characteristics of the braking resistor, the PWM control frequency f of the braking control signal received by the switching devices is... br The setting needs to be based on three considerations: First, frequencies higher than those sensitive to human hearing should be avoided to prevent noise; second, when the power interface module 20 is a bidirectional converter, frequencies should be lower than the bidirectional converter frequency (e.g., 10kHz~20kHz) to avoid harmonic coupling; third, within this range, the heat dissipation of the buffer circuit can be properly managed to prevent dv / dt from becoming very steep and generating spikes when the PWM wave controls the switching devices to turn off, to prevent overshoot caused by bus parasitic inductance, and to prevent rapid temperature rise of the switching device junction due to repetitive stress. In one example, the frequency f of the braking control signal... br It can be between 8kHz and 15kHz.

[0125] It is understood that traditional braking resistors only engage briefly during overvoltage, operating in a low-frequency or single-pulse mode, and their buffer circuits only need to provide basic shutdown protection. However, in this application, the switching devices need to operate under high thermal stress for milliseconds of continuous high-frequency chopping time, following the overflow power. Therefore, the buffer circuit used in this invention features specific parameter matching for this continuous braking condition to address the failure problem caused by accumulated thermal effects in conventional designs at high frequencies. The specific configuration principles are as follows:

[0126] First, determine or estimate the parasitic inductance Lσ of the bus loop (this can be obtained through finite element simulation based on the actual PCB stack-up and copper busbar layout, or by actual measurement of the physical prototype using an impedance analyzer; the parasitic inductance Lσ of the bus loop reflects the inductive characteristics generated by high-frequency current changes in the connection line). Then, determine the maximum turn-off current change rate di / dt of the switching device based on the drive circuit parameters and the switching characteristic curves in the device datasheet. max And set a maximum safe threshold ΔV for the peak voltage allowed to be superimposed on the DC bus. allow (e.g., ΔV) allow = V CES – V bus_max - V margin V CES This indicates the collector-emitter rated withstand voltage of a switching device; for example, devices with a 1200V rating are commonly used in 380V elevator systems. bus_max This indicates the maximum permissible DC bus operating voltage for the elevator system, such as 650V~750V; V margin This indicates an engineering safety margin, such as 50V~100V, reserved to prevent damage to switching devices due to overvoltage.

[0127] To adapt to high-frequency continuous chopping conditions, the buffer capacitor C sn The value of must strictly satisfy thermal balance and clamping constraints, such as: .

[0128] Secondly, the buffer resistor R sn The value of must satisfy the impedance matching principle to suppress parasitic oscillations in the circuit, such as: .

[0129] Finally, the buffer resistor R also needs to be adjusted. sn The power is verified. At the PWM switching frequency f set by the switching device. br Below, buffer resistor R sn Rated power P rating It needs to cover its theoretical energy consumption P loss ,like:

[0130]

[0131] With the above parameter configuration, the buffer circuit can not only protect the IGBT from overvoltage breakdown, but also ensure the buffer resistor R under high-frequency chopping conditions. sn However, it does not overheat, thus achieving linear power regulation of the braking module 30, improving the stability of PWM operation, and also enabling the braking module 30 to have long-term stable "analog load" characteristics, making its power linearly controllable by the duty cycle.

[0132] In some exemplary embodiments, please refer to Figure 6 The energy storage control device 100 of this application further includes:

[0133] The conversion module 60 is connected to the control module 50 and is used to connect to the DC bus of the frequency converter module 200 and to convert the first voltage signal of the DC bus to provide a power signal to the control module 50.

[0134] The redundant triggering module 70 is connected to the acquisition module 40, the conversion module 60 and the braking module 30 respectively, and is used to output redundant control signals according to the power supply signal and the bus monitoring signal; the redundant control signal is used to control the braking module 30 to be in full braking state.

[0135] The input terminal of the conversion module 60 is connected to the positive DC bus, and the output terminal of the conversion module 60 is connected to the control module 50 and the redundant trigger module 70. The conversion module 60 adopts a high-voltage flyback or buck switching power supply topology to convert the DC bus high voltage (such as 500V-750V) with a wide range of variation into a stable low-voltage DC power (such as 24V), providing a power signal for the energy storage control device 100, realizing electrical isolation between the high-voltage side and the low-voltage control side, and ensuring the electrical safety of the control system.

[0136] To ensure absolute system safety under extreme conditions such as software crashes, MCU failures, or auxiliary power fluctuations, this invention incorporates an independent redundant trigger unit outside the traditional software control loop. This unit is implemented using a purely analog hardware comparison circuit and is independent of the main controller's software operating state.

[0137] In one example, the bus monitoring signal includes a current monitoring signal and a voltage monitoring signal. The acquisition module 40 integrates a high-voltage sampling circuit and a Hall current sensor. The Hall current sensor is responsible for acquiring the bus current Ibus and outputting the current monitoring signal to the control module 50. The high-voltage sampling circuit performs voltage division processing on the bus voltage, outputting an analog voltage divider signal, i.e., the voltage monitoring signal. The control module 50 can calculate the bus voltage magnitude based on the magnitude of the analog voltage divider signal. Simultaneously, the high-voltage sampling circuit outputs the voltage monitoring signal to the redundant trigger module 70. It can be understood that when the voltage on the DC bus fluctuates, the voltage monitoring signal fluctuates accordingly; therefore, the fluctuation state of the voltage monitoring signal can characterize the fluctuation state of the bus voltage.

[0138] In one example, the redundancy triggering module 70 may include: an operational amplifier, the first input terminal of which is connected to the acquisition module 40, the second input terminal of which is connected to the conversion module 60, and the output terminal of which is connected to the braking module 30; the operational amplifier is used to output a redundancy control signal when the bus monitoring signal is greater than the power supply signal.

[0139] Specifically, when the power supply signal is less than the voltage monitoring signal, it indicates that the bus voltage is normal, the operational amplifier outputs a low level, and the braking module 30 is controlled by the braking control signal output by the control module 50; when the voltage monitoring signal is greater than the power supply signal, it indicates that the bus voltage is higher, the operational amplifier immediately flips to output a high level, that is, outputs a redundant control signal.

[0140] In the application, the output of the operational amplifier can be connected to the control terminal of the switching device in the braking module 30 via an OR gate logic circuit. This redundant control signal is accessed through the OR gate logic circuit to achieve logical overriding of the output signal of the control module 50. When the redundant trigger module 70 is activated, it bypasses the output of the control module 50, forcing all switching devices to conduct. Even if the control module 50 fails, as long as the power supply to the conversion module 60 is normal, the redundant trigger module 70 can work independently, forcibly limiting the bus voltage within the safe threshold range through the braking module 30.

[0141] In some exemplary embodiments, to prevent ineffective energy loss, this application also establishes strict software interlock logic. When the control module 50 determines that the energy storage control device 100 is in discharge support mode, regardless of the bus voltage fluctuation, the control module 50 forcibly sets the PWM duty cycle of the braking control signal to zero (D). brake =0). This interlock mechanism ensures absolute separation in timing between the energy output of the battery cell and the energy consumed by the braking module 30, preventing the braking module 30 from wasting the battery cell's power.

[0142] In some exemplary embodiments, this application also provides an energy storage control method, applied to the energy storage control device 100 in any of the above embodiments; please refer to... Figure 7 The energy storage control method of this application includes steps S701 to S704.

[0143] S701: Acquires battery status signals and bus monitoring signals.

[0144] S702: Obtain regeneration power and allowable charging power based on battery status signals and bus monitoring signals.

[0145] S703: Outputs current control signals to the power interface module based on battery status signals and bus monitoring signals.

[0146] S704: When the regeneration power exceeds the allowable charging power, output a braking control signal to the braking module.

[0147] In some exemplary embodiments, this application provides an energy storage control system, including a load, a frequency converter 200 connected to the load, and an energy storage control device 100 as described in any of the above embodiments.

[0148] The load may include elevators, or loads with similar operating characteristics to elevators, such as elevators, oil pumps, etc., which can generate regenerative energy and recycle it while consuming electricity.

[0149] In the description of this specification, references to terms such as "some embodiments," "other embodiments," and "ideal embodiments" indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0150] The technical features of the above embodiments can be combined in any way. For the sake of brevity, 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.

[0151] 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 the invention patent. 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 protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An energy storage control device, characterized in that, include: A battery energy storage module includes a battery cell and a management unit, wherein the management unit is used to acquire the battery status signal of the battery cell; A power interface module is connected to the battery energy storage module and is used to connect to the DC bus of the frequency converter module, and to adjust the charging and discharging current of the battery cell according to the received current control signal. A braking module, connected to the power interface module, is used to connect to the DC bus of the frequency converter module and to consume overflow power according to the received braking control signal; the overflow power is related to the regenerative power and the allowable charging power. The acquisition module is used to connect to the DC bus of the frequency converter module and to acquire bus monitoring signals; The control module is connected to the power interface module, the battery energy storage module, the acquisition module, and the braking module, respectively. It is used to obtain the regenerative power and the allowable charging power according to the battery status signal and the bus monitoring signal, output the current control signal according to the battery status signal and the bus monitoring signal, and output the braking control signal when the regenerative power exceeds the allowable charging power.

2. The energy storage control device according to claim 1, characterized in that, The power interface module includes: A bidirectional conversion unit is connected to the battery energy storage module and the control module respectively, and is used to connect to the DC bus of the frequency converter module; The control module is further configured to control the bidirectional conversion unit to be in a first conversion mode when the regeneration power is less than a preset power threshold, and to control the bidirectional conversion unit to be in a second conversion mode when the regeneration power is greater than the preset power threshold. In the first conversion mode, the battery energy storage module discharges to the frequency converter module; in the second conversion mode, the frequency converter module discharges to the battery energy storage module.

3. The energy storage control device according to claim 2, characterized in that, The bidirectional conversion unit includes an energy storage inductor; the battery status signal includes a battery total voltage signal. The control module is also used to determine the duty cycle of the current control signal based on the reference current signal, the current signal on the energy storage inductor, and preset control parameters. The reference current signal is related to the allowable charging power and the total battery voltage signal.

4. The energy storage control device according to claim 1, characterized in that, The power interface module includes: The current limiting unit is connected to the battery unit and the control module respectively, and is used to connect to the DC bus of the frequency converter module; The control module is further configured to determine the duty cycle of the current control signal based on the charging and discharging current, a preset reference charging and discharging current signal, and preset control parameters when the regeneration power exceeds the allowable charging power.

5. The energy storage control device according to claim 1, characterized in that, The braking module includes a braking resistor; The control module is further configured to determine the bus voltage of the DC bus based on the bus monitoring signal; the control module is further configured to determine the duty cycle of the braking control signal based on the overflow power, the resistance value of the braking resistor and the bus voltage when the regenerative power exceeds the allowable charging power.

6. The energy storage control device according to claim 1, characterized in that, The braking module includes: A braking resistor, the first end of which is used to connect to the first DC bus of the frequency converter module; A switching device, wherein a first terminal of the switching device is connected to a second terminal of the braking resistor, the second terminal of the switching device is used to connect to a second DC bus of the frequency converter module, and a control terminal of the switching device is used to receive the braking control signal; The switching device is used to adjust the equivalent input power of the braking resistor according to the braking control signal.

7. The energy storage control device according to claim 6, characterized in that, The braking module also includes: A buffer circuit is provided, wherein a first terminal of the buffer circuit is connected to a first terminal of the switching device, and a second terminal of the buffer circuit is connected to a second terminal of the switching device; the buffer circuit is used to suppress transient voltage spikes between the first and second terminals of the switching device.

8. The energy storage control device according to claim 1, characterized in that, The device further includes: A conversion module, connected to the control module, is used to connect to the DC bus of the frequency converter module and to convert the first voltage signal of the DC bus to provide a power signal to the control module. A redundant triggering module is connected to the acquisition module, the conversion module, and the braking module respectively, and is used to output a redundant control signal based on the power supply signal and the bus monitoring signal; the redundant control signal is used to control the braking module to be in a full braking state.

9. The energy storage control device according to claim 8, characterized in that, The redundant triggering module includes: An operational amplifier is provided, with its first input terminal connected to the acquisition module, its second input terminal connected to the conversion module, and its output terminal connected to the braking module. The operational amplifier is used to output a redundant control signal when the bus monitoring signal is greater than the power supply signal.

10. An energy storage control method, characterized in that, Applied to the energy storage control device according to any one of claims 1-9; the method includes: Acquire battery status signals and bus monitoring signals; The regeneration power and allowable charging power are obtained based on the battery status signal and the bus monitoring signal; Based on the battery status signal and the bus monitoring signal, the current control signal is output to the power interface module; If the regeneration power exceeds the allowable charging power, the braking control signal is output to the braking module.

11. An energy storage control system, characterized in that, It includes a load, a frequency converter connected to the load, and an energy storage control device as described in any one of claims 1-9.

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