A portable energy storage power supply device and method based on digital control technology

Abstract

The application relates to a portable energy storage power supply device and method based on digital control technology, which comprises a main controller and multiple sub-controllers, each of which is connected with a battery pack and is responsible for monitoring the state of the battery pack and performing charge and discharge control. In addition, the sub-controller further comprises an electric energy metering module, a temperature measuring module and a full-bridge driving module. The electric energy metering module collects and analyzes the working current, voltage and residual capacity of the battery pack in real time and transmits the results to the main controller. The temperature measuring module is used for monitoring the temperature of the battery pack, and when the temperature is abnormal or exceeds the threshold, an alarm is sent to the main controller. The full-bridge driving module is responsible for controlling the off state and current direction of the battery pack. The portable power supply device of the application provides power management functions such as battery state monitoring, charge and discharge control and safety protection, and through controlling the off state and current direction of each battery pack, a step-shaped discharge waveform similar to a sine wave is output, the function of converting the direct-current voltage of the battery into alternating-current output without a traditional inverter hardware structure can be realized, and the portable power supply device has high conversion efficiency, small size and weight, high power supply quality, reliable charge and discharge control and safety protection.

Description

Technical Field

[0001] This invention relates to the field of mobile energy storage technology, and more specifically to a portable energy storage power device and method based on digital control technology. Background Technology

[0002] Portable energy storage power supplies are portable energy storage devices that integrate battery packs, power management systems (BMS), input / output interfaces, and other components. They can store electrical energy and supply power when needed. In situations where power supply is unstable or cannot be connected to the conventional power grid, portable energy storage power supplies provide a reliable and immediate energy solution, enhancing autonomy and resilience in energy use. They not only improve the flexibility and convenience of energy use but also play a crucial role in promoting energy transition and sustainable development. The portable energy storage power supply market has continued to expand in recent years, particularly in areas such as outdoor adventure, emergency backup power, and power supply in remote areas. With the advancement of global energy transition and sustainable development, the portable energy storage power supply sector will usher in even broader development prospects.

[0003] Traditional mobile energy storage power supplies typically employ inverter-based power conversion schemes. The inverter is a key component connecting the energy storage system to the user equipment, responsible for converting the direct current (DC) from the storage battery into alternating current (AC) for use by various devices. The inverter operates based on the switching on and off of semiconductor switching transistors (such as MOSFETs). By precisely controlling the on and off times of these transistors, the inverter can generate AC power with the desired frequency and voltage. This process is typically achieved using pulse width modulation (PWM) technology, which changes the average value and frequency of the output voltage by altering the duty cycle of the switching transistors (i.e., the ratio of on time to total time). Currently, mobile energy storage power supplies on the market mainly employ the newer sinusoidal pulse width modulation (SPWM) technology for power conversion and management. SPWM is a modulation method used to generate an approximate sinusoidal output waveform and has been widely applied in motor control and renewable energy fields.

[0004] However, traditional inverter solutions suffer from high cost, large size and weight, low conversion efficiency, high heat generation, and short battery life, directly impacting the portability, efficiency, and safety of mobile energy storage power supplies. Firstly, the manufacturing materials and components of inverters, including high-quality semiconductor switching transistors, filter capacitors, inductors, and control circuit chips, all contribute to costs. Furthermore, while technological advancements have significantly optimized the size and weight of inverters, they can still be a limiting factor, especially in applications requiring high integration and lightweight design. Secondly, inverters generate heat during energy conversion, resulting in some electrical energy being lost as heat. Therefore, not only is the efficiency of the energy storage power supply low, but prolonged overheating can also pose safety hazards.

[0005] Therefore, how to provide an energy storage power device and power conversion method that differs from the traditional inverter structure in order to reduce the cost of inverter manufacturing materials and components, reduce the size and weight of the device, and significantly improve DC-AC conversion efficiency and safety to meet the needs of lightweight application scenarios has become a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a portable energy storage power supply device and method based on digital control technology, which can convert the DC voltage of a battery into AC power output without the need for a traditional inverter hardware structure. It features high conversion efficiency, small size and weight, higher power quality, more reliable charge and discharge control, and safety protection.

[0007] The specific plan is as follows:

[0008] One of the objectives of this invention is to provide a portable energy storage power device based on digital control technology, which has an MCU main controller and several MCU sub-controllers. The controllers interact with each other through a control bus to exchange data and control commands, thereby realizing the basic functions of a power management system (BMS), including battery status monitoring, charging and discharging control and safety protection.

[0009] Each MCU sub-controller is connected to a battery pack and is responsible for monitoring the status and controlling the charging and discharging of the battery pack. Each MCU sub-controller is equipped with an energy metering module, a temperature measurement module, and a full-bridge drive module. The energy metering module collects and analyzes the battery pack's operating current, voltage, and remaining charge in real time, and transmits this parameter information to the MCU main controller via the control bus at fixed intervals. The temperature measurement module monitors the battery pack's temperature in real time and sends an alarm message to the MCU main controller via the control bus when the temperature is abnormal or exceeds a threshold. The full-bridge drive module controls the battery pack's shutdown state and current direction.

[0010] The MCU main controller includes a battery status monitoring module, a safety protection module, a charging / discharging module, a storage module, and a display module. The battery status monitoring module receives and analyzes parameters such as battery pack operating current, voltage, and remaining capacity from various MCU sub-controllers, stores them, and performs statistical analysis to grasp the overall battery status of the power supply device, providing crucial reference information for guiding charging / discharging and safety protection strategies. The safety protection module formulates reasonable protection strategies for various aspects of the power supply device's safety based on the reference information provided by the battery status monitoring. The charging / discharging module, based on the reference information provided by the battery status monitoring and the power protection strategies required by the safety protection module, determines the shutdown state and current direction of each battery pack by directly controlling the full-bridge drive modules under each MCU sub-controller. The storage module stores some power supply device settings and historical usage records during power-off storage; this stored information will be used during power-on self-tests and equipment maintenance. The display module displays the basic user interface of the power supply device, providing display of various functions and user touchscreen interaction during use.

[0011] Furthermore, its energy storage battery supports modular installation. The battery packs of each MCU sub-controller are connected in series through a full-bridge drive module, serving as both power input and output to supply power to electrical equipment. For example... Figure 2 As shown, when the power supply is in discharge mode, it controls the off-state and current direction of each battery pack, causing the voltage values ​​of each battery pack to be superimposed to form a stepped discharge waveform that approximates a sine wave. Figure 3 As shown, when the power supply is in charging mode, unlike the discharging process, it is necessary to always keep the current direction consistent and to shut down each battery pack in time when the input charging voltage is in the negative half-cycle of the sine wave.

[0012] Furthermore, the full-bridge drive module is implemented based on a full-bridge drive chip, which is an integrated circuit used to control DC motors or stepper motors. It controls the direction and magnitude of the current to achieve forward and reverse rotation and speed regulation of the motor.

[0013] Furthermore, the power protection strategy includes overcurrent protection, overvoltage protection, undervoltage protection, load abnormality protection, and overheat protection.

[0014] Another objective of this invention is to provide a digital control method for the aforementioned portable energy storage power device. The goal of this digital control method is to rationally control the off-state and current direction of each battery pack while ensuring that each battery pack remains within its normal voltage range and safe temperature, thereby generating a stepped discharge waveform (approximately sinusoidal) in discharge mode. Figure 2 As shown), in charging mode, a stepped discharge waveform with only the positive half-cycle of a sine wave is formed (e.g. Figure 3 (As shown).

[0015] The digital control method for the portable energy storage power device of the present invention includes the following steps:

[0016] (1) Define the effective value of the output voltage of the power supply device when it discharges as V, and the frequency as f, i.e., a sinusoidal AC signal of v / f. Define the output accuracy of the power supply device as M, which represents the control frequency of the battery pack within a positive / negative half-cycle of a sinusoidal wave. It can be seen that the larger M is, the finer the stepped discharge waveform of the output is, i.e., the closer it is to a perfect sinusoidal signal, but at the same time, the requirements for control accuracy are also higher.

[0017] (2) Define the total number of battery packs in the power supply device as N, and know that the normal operating voltage of battery pack i is V. min and V max Between, the actual voltage V i The voltage will change with the remaining battery charge and load conditions. To ensure that the output voltage signal after the battery pack is stacked can approximately reconstruct the V / f sinusoidal AC signal, it is necessary to ensure... Right now α represents the redundancy of the power supply capacity, and the actual operating temperature of battery pack i is defined as T. i According to the requirements of the safety protection module, the operating temperature should not exceed T. max That is, T i ≤T max ;

[0018] (3) In the previous sine wave cycle, based on the actual voltage V of each battery pack i i and operating temperature T i Determine the off-time of each battery pack in the next sine wave cycle. and current direction in, This indicates that battery pack i is in the ON state during the m-th step of a sine wave cycle; conversely, it is in the OFF state during the m-th step of a sine wave cycle. Indicated as off state. This indicates that the direction of the current in battery pack i during the m-th step of a sine wave cycle makes the output voltage positive, and vice versa. Indicates the direction of the current, making the output voltage negative;

[0019] (4) Determine the shutdown state of each battery pack according to the control rules in the following steps (5)-(9). When the connected battery pack can no longer meet the output V / f sine wave AC signal, the discharge process ends and the power supply device displays or prompts an alarm message of insufficient power.

[0020] (5) When the power supply is in discharge mode, during the positive half-cycle of the sine wave, the current direction of each battery pack makes the voltage positive, and during the negative half-cycle of the sine wave, the current direction of each battery pack makes the voltage negative, that is:

[0021] (6) When the power supply is in charging mode, each battery pack should be in the off state during the negative half-cycle of the sine wave, i.e., it must meet the following requirements.

[0022] (7) When the actual operating temperature T of battery pack i i >T max At this time, the battery pack is temporarily shut down and does not participate in the discharge process; it will continue to cool down until it meets the T requirement. i ≤T max Afterwards, it can be reused as a backup battery pack for discharge;

[0023] (8) Possesses a high remaining power (which can be verified by actual voltage V) i Battery packs (indirectly estimated) not only qualify for priority discharge, but can also be allocated to longer continuous discharge times, thereby ensuring balanced discharge and reducing the risk of over-discharge of individual battery packs.

[0024] (9) Based on the output accuracy M, the approximate fitting of the sinusoidal AC signal is obtained by performing 2M uniform samplings on one complete cycle of the sine function, denoted as {V1, ... V... m , ..., V M}, where V m This represents the target output voltage at the m-th step within a sine wave cycle. The shutdown state of each battery pack is determined based on the optimization function.

[0025] Beneficial effects:

[0026] The portable power supply device of the present invention provides power management functions such as battery status monitoring, charge and discharge control and safety protection. By controlling the off state and current direction of each battery pack, it outputs a stepped discharge waveform with an approximate sine wave. It can realize the function of converting the battery DC voltage to AC output without the traditional inverter hardware structure. It has high conversion efficiency, small size and weight, higher power quality, more reliable charge and discharge control and safety protection.

[0027] The digital control method of the present invention features flexible charge and discharge control, efficient AC-DC conversion, and overheat safety protection. It solves many problems and shortcomings of traditional inverter-based power conversion schemes, and effectively improves the portability, reliability, and safety of power supply devices. Attached Figure Description

[0028] Figure 1This is a system architecture diagram of the portable energy storage power supply device provided by the present invention.

[0029] Figure 2 This is a schematic diagram of a discharge waveform according to an embodiment of the digital control method provided by the present invention.

[0030] Figure 3 This is a schematic diagram of a charging waveform according to an embodiment of the digital control method provided by the present invention.

[0031] Figure 4 The image shows an actual discharge waveform of an embodiment of the digital control method provided by the present invention. Detailed Implementation

[0032] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0033] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0034] This invention provides a portable energy storage power device based on digital control technology, which has a main controller and several sub-controllers. The single main controller and multiple sub-controllers typically use microcontrollers (MCUs) based on the ARM / MIPS architecture as the core processor platform, such as STMicroelectronics' STM32 series.

[0035] The controllers can exchange data and control commands via the CAN bus to realize the basic functions of a BMS, including battery status monitoring, charge and discharge control, and safety protection.

[0036] Each MCU sub-controller is directly connected to a corresponding battery pack, responsible for monitoring the battery pack's status and controlling its charging and discharging. Each MCU sub-controller includes an energy metering module, a temperature measurement module, and a full-bridge drive module. A single, dedicated MCU master controller serves as the control core of the power supply unit, coordinating the operating modes of all MCU sub-controllers, essentially acting as the central control unit of a BMS system.

[0037] The full-bridge driver module is a key design element for charging and discharging functions in a power supply unit. It can be implemented using a full-bridge driver chip. A full-bridge driver chip is an integrated circuit used to control DC motors or stepper motors. It controls the direction and magnitude of the current to achieve functions such as forward and reverse rotation and speed regulation. Its principle is to use internal switching devices (such as MOSFETs) to control the direction of current flow. Typically, a full-bridge driver chip contains four switching devices, which in this embodiment can be used to control the battery pack's off-state and the direction of current flow.

[0038] According to the portable energy storage power device described, a battery pack can be constructed by connecting multiple lithium batteries in series. The energy storage battery supports modular installation; each lithium battery pack is connected in series via a full-bridge drive module, serving as both the power input and output to supply power to electrical devices. Taking China as an example, the standard voltage commonly used in household appliances is 220V / 50Hz, i.e., V = 220V, f = 50Hz. Furthermore, the normal operating voltage of a single lithium battery is between 3.7V and 4.2V. If a battery pack consists of four lithium batteries connected in series, then V... min =3.7 × 4 = 14.8 V, V max =4.2×4=16.8V.

[0039] Set the redundancy of the power supply capacity to α = 2, according to Calculated, i.e. The total number of battery packs can be 43.

[0040] The output accuracy M of the power supply unit represents the control frequency of the battery pack within one positive / negative half-cycle of a sine wave. Setting the output accuracy M to 15, as shown... Figure 2 and Figure 3 As shown, the discharge waveform of a sine wave's positive and negative half-cycles is formed by the superposition of 15 stepped signals. Therefore, the larger M is, the finer the output stepped discharge waveform, that is, the closer it is to a perfect sine wave signal. However, this also places higher demands on the operating frequency and program control precision of the MCU main controller. For example, the operating frequency of an STM32 MCU is typically around 180MHz, and the output precision M needs to be quantized based on this value to determine the optimal value.

[0041] Digital control methods can precisely control the charging and discharging process of the power supply, thereby converting the battery's DC voltage into a 220V / 50Hz AC output. The goal of digital control is to rationally control the off-state and current direction of each battery pack while ensuring they remain within their normal voltage range and safe temperature, thus generating a near-sinusoidal stepped discharge waveform (e.g., ...) during discharge. Figure 2 As shown), in charging mode, a stepped discharge waveform with only the positive half-cycle of a sine wave is formed (e.g. Figure 3 (As shown).

[0042] When the power supply is operating in discharge mode, during the positive half-cycle of the sine wave, the current direction of each battery pack results in a positive voltage; during the negative half-cycle of the sine wave, the current direction of each battery pack results in a negative voltage.

[0043] When the power supply is in charging mode, each battery pack should be in the off state during the negative half-cycle of the sine wave, which means it must meet the following requirements.

[0044] Lithium-ion batteries typically operate within a temperature range of -20°C to 60°C. Within this temperature range, the performance and safety of lithium-ion batteries are well-assured. Therefore, the operating temperature of each battery pack should not exceed T. max =60℃. When the actual operating temperature T of battery pack i is... i When the temperature exceeds 60℃, the battery pack is temporarily shut off and does not participate in the discharge process; it will continue to cool down to meet the T requirement. i After reaching ≤60℃, it can be reused as a backup battery pack for discharge.

[0045] Based on an output precision of M=15, an approximate fit to a sinusoidal AC signal can be obtained by performing 30 uniform samples over one complete cycle of the sine function. Therefore, {V1, ... V m , ..., V 30 The integer values ​​of} are: 0V, 65V, 126V, 183V, 231V, 269V, 296V, 309V, 309V, 296V, 269V, 231V, 183V, 126V, 65V, 0V, -65V, -126V, -183V, -231V, -269V, -296V, -309V, -309V, -296V, -269V, -231V, -183V, -126V, -65V.

[0046] The digital control method determines the shutdown state of each battery pack based on the following optimization function:

[0047] Among them, V i This is the actual operating voltage of battery pack i. This represents the off-state of battery pack i at the m-th step of a sine wave cycle. It's worth noting that battery packs with higher remaining charge not only qualify for priority discharge but can also be allocated longer continuous discharge times, thus ensuring balanced discharge and reducing the risk of over-discharge in individual battery packs.

[0048] When the connected battery pack is no longer able to output a 220V / 50Hz sine wave AC signal, the discharge process ends, and the power supply device displays or prompts an alarm message indicating insufficient power.

[0049] According to the digital control method provided by the present invention, when the output accuracy M = 30, the actual discharge waveform is as follows: Figure 4 As shown.

[0050] The digital control method of the present invention features flexible charge and discharge control, efficient AC-DC conversion, and overheat safety protection. It solves many problems and shortcomings of traditional inverter-based power conversion schemes, and effectively improves the portability, reliability, and safety of power supply devices.

[0051] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A portable energy storage power supply device based on digital control technology, characterized in that, An MCU main controller and a plurality of MCU sub-controllers are provided, and data and control instructions are exchanged between the controllers through a control bus; The MCU sub-controllers are connected to a group of battery packs respectively, and are used for monitoring the state of the battery packs and controlling the charging and discharging of the battery packs. The MCU sub-controllers are respectively provided with an electric energy metering module, a temperature measuring module and a full-bridge driving module. The electric energy metering module is used for collecting and analyzing the parameters of the working current, voltage and residual capacity of the battery packs in real time, and transmitting the parameter information to the MCU main controller through the control bus at a fixed period. The temperature measuring module is used for monitoring the temperature value of the battery packs in real time, and sending an alarm message to the MCU main controller through the control bus when the temperature is abnormal or exceeds a threshold value. The full-bridge driving module is used for controlling the off state and current direction of the battery packs. The MCU main controller is provided with a battery state monitoring module, a safety protection module, a charging and discharging module, a storage module and a display module. The battery state monitoring module is used for receiving the parameters of the working current, voltage and residual capacity of the battery packs collected and analyzed by the MCU sub-controllers, storing and performing mathematical statistical analysis, so as to master the overall battery state of the power supply device, and serve as important reference information for guiding the charging and discharging and safety protection strategy. The safety protection module is used for making reasonable protection strategy for each safety of the power supply device according to the reference information provided by the battery state monitoring. The charging and discharging module is used for determining the off state and current direction of each battery pack by directly controlling the full-bridge driving module under each MCU sub-controller according to the reference information provided by the battery state monitoring and the power supply protection strategy required by the safety protection module. The storage module is used for power failure storage of part of the setting parameters and historical use record information of the power supply device, and these storage information will be used during power-on self-test and equipment maintenance of the power supply device. The display module is used for displaying the basic user interface of the power supply device. The effective value of the output voltage of the power supply device at the time of discharging is defined as ; Let the total number of battery packs in the power supply device be , and let the normal working voltage of the battery pack be between and . The actual voltage will vary with the remaining battery capacity and the load. In order to ensure that the output voltage signal of the stacked battery packs can approximately restore the sinusoidal AC signal of , it is necessary to ensure that , that is, , represents the redundancy of the power supply capacity.

2. The portable energy storage power source device of claim 1, wherein, The battery packs of each MCU sub-controller are connected in series through the full-bridge driving module, and are used as the input and output of the power supply, thereby supplying power for the power consumption equipment.

3. The portable energy storage power source device of claim 1, wherein, The full-bridge driving module is realized based on a full-bridge driving chip. The full-bridge driving chip is an integrated circuit used for controlling a direct current motor or a stepping motor, and the direction and size of the current are controlled to realize the forward rotation, reverse rotation and speed regulation of the motor.

4. The portable energy storage power source device of claim 1, wherein, The power supply protection strategy includes overcurrent protection, overvoltage protection, undervoltage protection, load abnormal protection and overheat protection.

5. The digital control method of a portable energy storage power supply device according to any one of claims 1-4, characterized in that, The method comprises the following steps: (1) defining the effective value of the output voltage of the power supply device at the time of discharging as , the frequency as , that is, a sinusoidal AC signal of , and defining the output accuracy of the power supply device as , indicating the control frequency to the battery pack within one positive / negative half cycle of the sinusoidal wave; (2) define the total number of battery packs in the power supply device as , given that the normal operating voltage of the battery pack is between and , and the actual voltage will change with the remaining battery capacity and load conditions, in order to ensure that the output voltage signal of the stacked battery packs can approximately restore the sine wave AC power signal of , it is necessary to ensure that , that is , represents the redundancy of the power supply capacity, and the actual operating temperature of the battery pack is defined as , according to the requirements of the safety protection module, the operating temperature should not be greater than , that is ; (3) In the previous sine wave cycle, according to each battery pack actual voltage and operating temperature Determine the off-time of each battery pack in the next sine wave cycle. and current direction ,in, Indicates battery pack In the first cycle of a sine wave In the first step, the system is in the "on" state; conversely, in the second step, it is in the "off" Indicated as off state. Indicates battery pack In the first cycle of a sine wave The direction of the current in each step makes the output voltage positive, and vice versa. Indicates the direction of the current, making the output voltage negative; (4) According to the control rules of steps (5)-(9), the off state of each battery pack is determined, and when the connected battery pack can no longer meet the output of the sine wave alternating current signal, the discharging process ends, and the power supply device displays or prompts an alarm message of insufficient power. of the sine wave alternating current signal, the discharging process ends, and the power supply device displays or prompts an alarm message of insufficient power. (5) When the power supply is in the discharging mode, during the positive half cycle of the sinusoidal wave, the current direction of each battery pack is such that the voltage is positive, and during the negative half cycle of the sinusoidal wave, the current direction of each battery pack is such that the voltage is negative, i.e.: ; (6) When the power supply is in the charging mode, in the negative half cycle of the sine wave, each battery pack should be in the off state, i.e. it is necessary to satisfy ; (7) When the battery pack Actual operating temperature At this time, the battery pack is temporarily shut down and does not participate in the discharge process; it will continue to cool down until it meets the required temperature. Afterwards, it can be reused as a backup battery pack for discharge; (8) The battery packs with higher residual capacity are preferentially discharged, and are allocated longer continuous discharging time, so as to ensure discharging balance and reduce the risk of over-discharging of individual battery packs. (9) Based on output accuracy The approximate fitting of a sinusoidal alternating current signal is achieved by performing a complete cycle of the sinusoidal function. Obtained by uniform sampling, denoted as ,in This represents the first digit of a sine wave period. The target output voltage for each step is determined by the optimization function, which determines the shutdown state of each battery pack. .

6. The digital control method of claim 5, wherein: The step (8) by the actual voltage Estimate the battery pack with higher remaining power.

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