Uninterruptible power supply system and method for air compressor control system

Abstract

The invention relates to the technical field of air compressor control, and particularly discloses an uninterruptible power supply system and method for an air compressor control system, a main power supply module outputs stable voltage through filtering, power factor correction and voltage stabilization processing; and the standby power supply module takes the lithium iron phosphate storage battery pack as a core and is matched with the conversion circuit to output same-frequency and same-phase alternating current. And the switching regulation and control module realizes gapless switching between the main power and the standby power through synchronous detection and the bidirectional thyristor switch group. The state monitoring module collects data in multiple dimensions, the intelligent control module analyzes the state and issues an instruction based on the DSP controller, and the energy storage management module achieves accurate charging and discharging and battery equalization adjustment. Power supply is continuous and stable, quality is high, energy consumption is low, operation and maintenance are convenient, continuous operation of the air compressor control system can be guaranteed, and production interruption is avoided.

Description

Technical Field

[0001] This invention relates to the field of air compressor control technology, specifically to an uninterruptible power supply system and method for an air compressor control system. Background Technology

[0002] As a core power equipment in industrial production, the stable operation of the air compressor's control system directly determines its reliability, air production efficiency, and operational safety. Air compressor control systems typically integrate components such as controllers, sensors, actuators, and human-machine interface modules, and have extremely high requirements for the stability and continuity of the power supply voltage. Existing air compressor control systems mostly use direct mains power supply or simple backup power switching, which has many drawbacks: First, the mains power grid is susceptible to voltage fluctuations, surges, harmonic interference, and sudden power outages, causing instantaneous power loss or malfunctions in the control system, leading to air compressor shutdowns and pressure loss, which not only affects production continuity but may also cause mechanical damage to equipment. Second, traditional backup power switching has a delayed response, with millisecond-level power interruptions during the switching process, which cannot meet the stringent requirements of the control system for uninterrupted power supply. Furthermore, the charging and discharging management of backup power is rudimentary, resulting in short battery life and low power supply reliability. Third, existing power supply systems lack targeted status monitoring and intelligent control capabilities, cannot dynamically adjust power supply parameters according to the air compressor's operating load, have high energy consumption, and are difficult to predict power supply failures in advance, which is not conducive to preventive maintenance of equipment. Therefore, there is an urgent need to design a fast-responding, stable, reliable, intelligent and efficient uninterruptible power supply system and method for air compressor control systems to solve the above-mentioned technical problems. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an uninterrupted power supply system and method for an air compressor control system, so as to realize seamless power supply to the air compressor control system when the mains power is abnormal or interrupted, improve the stability and reliability of power supply, and at the same time have intelligent monitoring, dynamic control and fault early warning functions, reduce energy consumption and extend the service life of equipment. To solve the above-mentioned technical problems, the technical solution provided by the present invention is: an uninterruptible power supply system for an air compressor control system, comprising a main power supply module, a backup power supply module, a switching and control module, a status monitoring module, an intelligent control module, and an energy storage management module; The main power supply module is used to connect to the mains power, and after filtering and stabilizing the mains power, it provides the rated operating voltage to the air compressor control system. The backup power supply module includes an energy storage unit, a bidirectional DC / DC converter, and an inverter. The energy storage unit uses a lithium iron phosphate battery pack. The bidirectional DC / DC converter is used for bidirectional energy transfer between the energy storage unit and the DC bus. The inverter is used to convert the DC power output by the energy storage unit into AC power that is in the same frequency and phase as the mains power, so as to supply power to the air compressor control system. The switching control module includes a bidirectional thyristor switch group, a synchronization detection circuit, and a drive circuit. The synchronization detection circuit detects the phase, frequency, and amplitude of the output voltage of the main power supply module and the output voltage of the backup power supply module in real time. The drive circuit drives the bidirectional thyristor switch group to operate according to the synchronization detection results, so as to realize seamless switching between the main power supply and the backup power supply. The status monitoring module includes a voltage sensor, a current sensor, a temperature sensor, a SOC sensor, and a harmonic detector, which are used to collect the main power supply voltage, the backup power supply current, the temperature of the energy storage unit, the remaining power of the energy storage unit, and the harmonic content of the power supply line, respectively, and transmit the collected monitoring data to the intelligent control module. The intelligent control module adopts a DSP controller, which is electrically connected to the main power supply module, the backup power supply module, the switching and control module, the status monitoring module and the energy storage management module respectively. It is used to receive monitoring data, determine the power supply status, and issue switching control commands, energy storage control commands and fault warning commands. The energy storage management module is electrically connected to the energy storage unit and the bidirectional DC / DC converter. It is used to realize constant current charging, constant voltage charging and discharge protection of the energy storage unit according to the instructions of the intelligent control module, and at the same time monitor the voltage balance status of the individual batteries in the energy storage unit and actively balance and adjust the unbalanced batteries. Furthermore, the main power supply module includes an EMI filter, a power factor correction circuit, and an isolated voltage regulator connected in sequence, wherein the isolated voltage regulator adopts a flyback topology. Furthermore, the lithium iron phosphate battery pack of the energy storage unit adopts a series-parallel combination structure. The capacity of each battery cell is configured according to the rated power of the air compressor control system and the backup power supply duration. It is also equipped with a battery management unit to monitor the voltage, temperature and internal resistance of each battery cell in real time. Furthermore, the intelligent control module has a built-in power supply status judgment algorithm. The power supply status includes normal mains power status, abnormal mains power status, and mains power interruption status. The abnormal mains power status includes voltage fluctuation exceeding the standard, harmonic exceeding the standard, and surge. The intelligent control module triggers corresponding control strategies according to different power supply statuses. The present invention also provides an uninterrupted power supply method for an air compressor control system, comprising the following steps: S1. After the intelligent control module starts, it performs self-tests on each module, including the working status of the main power supply module, backup power supply module, switching control module and status monitoring module. If a fault is found, an early warning signal will be issued immediately. If the self-test passes, it will enter the standby power supply state. S2. The main power supply module is connected to the mains power. After the EMI filter removes the grid harmonics and interference signals, the power factor is improved to above 0.98 by the power factor correction circuit. Then, the isolated voltage regulator outputs a stable voltage to power the air compressor control system. At the same time, the energy storage management module controls the bidirectional DC / DC converter to work and use the mains power to charge the energy storage unit with constant current until the energy storage unit SOC reaches 80%. Then it switches to constant voltage charging and stops charging when the SOC reaches 95%. S3. The status monitoring module continuously collects the main power supply voltage, current, harmonic content, backup power supply circuit current, SOC, temperature and individual battery voltage of the energy storage unit, and transmits the monitoring data to the intelligent control module in real time. The intelligent control module analyzes the power supply status through the power supply status judgment algorithm. S4. When the intelligent control module determines that the mains power is normal, it maintains the main power supply mode. When it determines that the mains power is abnormal, such as voltage fluctuation exceeding ±10%, harmonic content exceeding the limit of GB / T 14549 standard, or surge, the control switching module prepares for switching in advance, and simultaneously detects the voltage phase and frequency of the main power supply and the backup power supply. When the mains power abnormality reaches the preset threshold, it drives the bidirectional thyristor switch group to switch to the backup power supply module without gap, and the energy storage unit supplies power through the inverter. When the mains power is interrupted, the switching control module triggers the switching instantly to ensure uninterrupted power supply. When the mains power returns to normal and runs stably for 30 seconds, it switches back to the main power supply mode and charges the energy storage unit at the same time. S5. During the discharge process of the energy storage unit, the energy storage management module monitors the SOC in real time. When the SOC drops to 20%, a low power warning is issued, and the energy storage unit is controlled to stop discharging to avoid damage from over-discharge. During the charging process, the battery management unit monitors the voltage of individual batteries. If there is a voltage imbalance, where the voltage difference between individual batteries is ≥0.1V, the active balancing circuit is activated to adjust the charging and discharging current of individual batteries to achieve voltage balancing. The S6 intelligent control module analyzes the monitoring data in real time. If overvoltage, overcurrent, short circuit, excessive temperature of energy storage unit, or single battery failure is detected, the corresponding power supply circuit is immediately cut off, a fault warning signal is issued, and the protection mechanism is activated to ensure the safety of the system and the air compressor control system. The advantages of this invention compared to the prior art are: This invention employs a contactless bidirectional thyristor switch group and synchronous detection technology, and avoids inrush current through zero-crossing triggering, thus solving the power interruption problem of traditional switching methods. This ensures the continuous and stable operation of the air compressor control system and avoids equipment shutdown and production interruption due to power supply problems. The main power supply module of this invention undergoes multi-stage filtering, voltage stabilization, and power factor correction, resulting in high output voltage accuracy and strong anti-interference capability. Meanwhile, the backup power supply module uses a lithium iron phosphate battery pack and a high-efficiency conversion circuit to ensure that the backup power supply quality is consistent with the main power supply, thus meeting the stringent power quality requirements of the air compressor control system. This invention enables real-time judgment and dynamic regulation of power supply status through an intelligent control module. Combined with the precise charging and discharging control and battery balancing adjustment of the energy storage management module, it extends the service life of the energy storage unit, while improving the energy utilization efficiency of the power supply system and reducing ineffective energy consumption. This invention has comprehensive fault monitoring and protection functions, which can predict problems such as abnormal mains power and energy storage unit failures in advance and issue early warnings. At the same time, each module has an independent structure and convenient self-testing, which facilitates later maintenance and repair and reduces equipment operation and maintenance costs. Attached Figure Description Figure 1 This is a system block diagram of an uninterruptible power supply system for an air compressor control system according to the present invention. Figure 2 This is a flowchart of an uninterrupted power supply method for an air compressor control system according to the present invention. Detailed Implementation Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. The following detailed description, in conjunction with the accompanying drawings, provides an uninterruptible power supply system and method for an air compressor control system according to the present invention. Combined with appendix Figure 1-2 This invention will be described in detail below. An uninterruptible power supply system for an air compressor control system includes a main power supply module, a backup power supply module, a switching and control module, a status monitoring module, an intelligent control module, and an energy storage management module. The main power supply module is used to connect to the mains power. After filtering and stabilizing the mains power, it provides the rated operating voltage to the air compressor control system. It includes an EMI filter, a power factor correction circuit and an isolated regulated power supply connected in sequence. The backup power supply module includes an energy storage unit, a bidirectional DC / DC converter, and an inverter. The energy storage unit uses a lithium iron phosphate battery pack. The bidirectional DC / DC converter is used to realize bidirectional energy transfer between the energy storage unit and the DC bus. The inverter is used to convert the DC power output by the energy storage unit into AC power that is in the same frequency and phase as the mains power to power the air compressor control system. The switching control module adopts a contactless switching structure, including a bidirectional thyristor switch group, a synchronous detection circuit and a drive circuit. The synchronous detection circuit detects the phase, frequency and amplitude of the output voltage of the main power supply module and the output voltage of the backup power supply module in real time. The drive circuit drives the bidirectional thyristor switch group to operate according to the synchronous detection results, so as to realize seamless switching between the main power supply and the backup power supply. The status monitoring module includes a voltage sensor, a current sensor, a temperature sensor, a SOC sensor, and a harmonic detector, which are used to collect the main power supply voltage, the backup power supply current, the temperature of the energy storage unit, the remaining power of the energy storage unit, and the harmonic content of the power supply line, respectively, and transmit the collected monitoring data to the intelligent control module. The intelligent control module uses a DSP controller, which is electrically connected to the main power supply module, backup power supply module, switching control module, status monitoring module and energy storage management module respectively. It is used to receive monitoring data, judge the power supply status, and issue switching control commands, energy storage control commands and fault warning commands. The energy storage management module is electrically connected to the energy storage unit and the bidirectional DC / DC converter. It is used to realize constant current charging, constant voltage charging and discharge protection of the energy storage unit according to the instructions of the intelligent control module. At the same time, it monitors the voltage balance status of the individual batteries in the energy storage unit and actively balances and adjusts unbalanced batteries. The isolated regulated power supply of the main power supply module adopts a flyback topology, with the output voltage accuracy controlled within ±0.5%, and has overvoltage, overcurrent and short-circuit protection functions. The switching response time of the switching control module is ≤100 microseconds, and the bidirectional thyristor switch group adopts zero-crossing triggering mode to avoid inrush current during the switching process. The energy storage unit's lithium iron phosphate battery pack adopts a series-parallel combination structure. The capacity of each battery cell is configured according to the rated power of the air compressor control system and the backup power supply duration. It is also equipped with a battery management unit (BMU) to monitor the voltage, temperature and internal resistance of each battery cell in real time. The intelligent control module has a built-in power supply status judgment algorithm, including normal mains power status, abnormal mains power status, and mains power interruption status, and triggers corresponding control strategies according to different statuses. The present invention also provides an uninterrupted power supply method for an air compressor control system, based on the above system, comprising the following steps: S1. System Initialization: After the intelligent control module starts, it performs self-checks on each module, including the working status of the main power supply module, backup power supply module, switching control module and status monitoring module. If a fault is found, an early warning signal will be issued immediately. If the self-check passes, it will enter the standby power supply state. S2. Main power supply operation: The main power supply module is connected to the mains power. After the EMI filter removes grid harmonics and interference signals, the power factor is improved to above 0.98 by the power factor correction circuit. Then, the isolated voltage regulator outputs a stable voltage to power the air compressor control system. At the same time, the energy storage management module controls the bidirectional DC / DC converter to work and use the mains power to charge the energy storage unit with constant current until the energy storage unit SOC reaches 80%. Then, it switches to constant voltage charging and stops charging when the SOC reaches 95%. S3. Real-time status monitoring: The status monitoring module continuously collects the main power supply voltage, current, harmonic content, backup power supply circuit current, SOC, temperature and single cell voltage of the energy storage unit, and transmits the monitoring data to the intelligent control module in real time. The intelligent control module analyzes the power supply status through the power supply status judgment algorithm. S4. Power Supply Switching Control: When the intelligent control module determines that the mains power is normal, it maintains the main power supply mode; when it determines that the mains power is abnormal, the control switching module prepares for switching in advance, and simultaneously detects the voltage phase and frequency of the main power supply and the backup power supply. When the mains power abnormality reaches the preset threshold, it drives the bidirectional thyristor switch group to switch to the backup power supply module without gap, and the energy storage unit supplies power through the inverter; when the mains power is interrupted, the switching control module triggers the switching instantly to ensure uninterrupted power supply; when the mains power returns to normal and operates stably for 30 seconds, it switches back to the main power supply mode, and charges the energy storage unit at the same time. S5, Energy Storage Management: During the discharge process of the energy storage unit, the energy storage management module monitors the SOC in real time. When the SOC drops to 20%, a low power warning is issued, and the energy storage unit is controlled to stop discharging to avoid damage from over-discharge. During the charging process, the battery management unit monitors the voltage of individual batteries. If there is a voltage imbalance, the active balancing circuit is activated to adjust the charging and discharging current of individual batteries to achieve voltage balance. S6. Fault Warning and Protection: The intelligent control module analyzes the monitoring data in real time. If overvoltage, overcurrent, short circuit, excessive temperature of energy storage unit or single battery failure is detected, the corresponding power supply circuit will be cut off immediately, a fault warning signal will be issued, and the protection mechanism will be activated at the same time to ensure the safety of the system and the air compressor control system. The specific implementation process of the uninterruptible power supply system and method for an air compressor control system of the present invention is as follows: An uninterruptible power supply system for an air compressor control system, adapted to an air compressor control system with a rated power of 5kW, is configured as follows: Main power supply module: The EMI filter adopts a two-stage filtering structure, which can filter out interference signals in the 10kHz-1GHz frequency band; the power factor correction circuit adopts a Boost topology, with an operating frequency of 100kHz, and the power factor is improved to above 0.98; the isolated regulated power supply is a flyback topology, with an input voltage range of AC 220V±20%, an output voltage of DC 24V, an accuracy of ±0.3%, and overvoltage, overcurrent, and short circuit protection functions. Backup power supply module: The energy storage unit adopts a 16-series 8-parallel lithium iron phosphate battery pack, with a single battery capacity of 100Ah and a total capacity of 800Ah, and a rated voltage of 51.2V; the bidirectional DC / DC converter operates at a frequency of 200kHz and has a conversion efficiency of ≥96%; the inverter output is AC 220V, 50Hz, with a waveform distortion of ≤3% and a rated power of 6kW, meeting the peak load requirements of the air compressor control system. Switching and control module: The bidirectional thyristor switch group uses bidirectional thyristors of model TSR-250A. The synchronization detection circuit adopts a voltage comparator and a phase-locked loop chip to achieve precise synchronization of phase and frequency. The switching response time is 80 microseconds and the zero-crossing trigger error is ≤5 microseconds. Status monitoring module: The voltage sensor has an accuracy of 0.2 class, the current sensor adopts a Hall effect sensor with an accuracy of 0.5 class, the temperature sensor has a measurement range of -20℃ to 80℃ and an accuracy of ±0.5℃, the SOC sensor has a measurement accuracy of ±2%, and the harmonic detector can detect 3rd to 50th harmonics, which meets the requirements of GB / T 14549 standard. The intelligent control module uses TI's TMS320F28335 DSP controller with a clock frequency of 150MHz. It has built-in power supply status judgment algorithm and fault diagnosis algorithm, and supports RS485 communication interface, which can upload monitoring data and fault information to the host computer of the air compressor control system. Energy storage management module: Equipped with a dedicated battery management unit (BMU) that can monitor the status of 128 individual cells. The active balancing circuit adopts a capacitor balancing topology with a balancing current of 1A, a constant current of 10A during charging, a constant voltage of 54.6V, a discharge protection voltage of 40V, and a temperature protection threshold of 55℃. The uninterruptible power supply method for the air compressor control system based on the above system is implemented in the following steps: System initialization: After the DSP controller starts, it sequentially checks whether the EMI filter, power factor correction circuit, and regulated power supply of the main power supply module, the bidirectional DC / DC converter and inverter of the backup power supply module, the thyristor switch group and synchronous detection circuit of the switching control module, and the sensors of the status monitoring module are working properly. After the self-test is passed, the host computer displays "Power supply system ready" and enters the standby power supply state. Main power supply operation: Connected to AC 220V mains power, the power supply is filtered out by an EMI filter to remove grid interference. The Boost topology power factor correction circuit corrects the input current to a sine wave, achieving a power factor of 0.985. The flyback regulated power supply outputs a stable DC 24V voltage to power components such as the air compressor controller, pressure sensor, and solenoid valve. At the same time, the energy storage management module controls the bidirectional DC / DC converter to charge the battery pack at a constant current of 10A. When the SOC reaches 80%, it switches to 54.6V constant voltage charging, and stops charging when the SOC reaches 95%. At this time, the battery pack's stored energy can meet the continuous operation of the air compressor control system for 4 hours. Real-time status monitoring: Each sensor collects data every 10 milliseconds. The voltage sensor monitors the main power supply output voltage as 24V±0.072V, the harmonic detector monitors the third harmonic content as 1.2%, the SOC sensor monitors the battery pack SOC as 95%, and the temperature sensor monitors the battery temperature as 28℃. All data is transmitted to the DSP controller in real time. Power supply switching control: When a surge occurs in the mains power, the main power supply voltage instantly rises to 28V. The DSP controller immediately detects the mains power anomaly and simultaneously detects the voltage phase and frequency of the main power supply and the backup power supply. Within 0.08 milliseconds, it drives the bidirectional thyristor switch group to switch to the backup power supply module. The inverter outputs AC 220V voltage, which is regulated and then used to power the control system. There are no abnormalities in the control system during the switching process. After 3 minutes, the mains power returns to normal, and the main power supply voltage stabilizes at 24V±0.072V. After running stably for 30 seconds, it switches back to the main power supply mode and starts charging the battery pack. Energy storage management: During the discharge process of the battery pack, when the SOC drops to 20%, the DSP controller issues a low power warning, and the host computer displays "Backup power low power". At the same time, the energy storage management module controls the battery pack to stop discharging. During the charging process, the BMU detects that the voltage of a certain single cell is 0.12V higher than that of other cells, and starts the active balancing circuit to adjust the charging current of the cell. After 10 minutes, the voltage difference of the single cell drops to within 0.05V, achieving voltage balancing. Fault warning and protection: When the battery pack temperature rises to 56°C due to the ambient temperature, the temperature sensor transmits the signal to the DSP controller. The controller immediately cuts off the backup power supply circuit, issues a "energy storage unit overheating" warning signal, and starts the cooling fan to cool down. When the temperature drops below 45°C, the backup power supply circuit is restored. In this embodiment, the uninterruptible power supply system can realize seamless power supply to the air compressor control system when the mains power is abnormal or interrupted. It has high power supply stability, low energy consumption, timely fault warning, and effectively ensures the continuous and reliable operation of the air compressor. The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. An uninterruptible power supply system for an air compressor control system, characterized by: It includes a main power supply module, a backup power supply module, a switching and control module, a status monitoring module, an intelligent control module, and an energy storage management module; The main power supply module is used to connect to the mains power, and after filtering and stabilizing the mains power, it provides the rated operating voltage to the air compressor control system. The backup power supply module includes an energy storage unit, a bidirectional DC / DC converter, and an inverter. The energy storage unit uses a lithium iron phosphate battery pack. The bidirectional DC / DC converter is used for bidirectional energy transfer between the energy storage unit and the DC bus. The inverter is used to convert the DC power output by the energy storage unit into AC power that is in the same frequency and phase as the mains power, so as to supply power to the air compressor control system. The switching control module includes a bidirectional thyristor switch group, a synchronization detection circuit, and a drive circuit. The synchronization detection circuit detects the phase, frequency, and amplitude of the output voltage of the main power supply module and the output voltage of the backup power supply module in real time. The drive circuit drives the bidirectional thyristor switch group to operate according to the synchronization detection results, so as to realize seamless switching between the main power supply and the backup power supply. The status monitoring module includes a voltage sensor, a current sensor, a temperature sensor, a SOC sensor, and a harmonic detector, which are used to collect the main power supply voltage, the backup power supply current, the temperature of the energy storage unit, the remaining power of the energy storage unit, and the harmonic content of the power supply line, respectively, and transmit the collected monitoring data to the intelligent control module. The intelligent control module adopts a DSP controller, which is electrically connected to the main power supply module, the backup power supply module, the switching and control module, the status monitoring module and the energy storage management module respectively. It is used to receive monitoring data, determine the power supply status, and issue switching control commands, energy storage control commands and fault warning commands. The energy storage management module is electrically connected to the energy storage unit and the bidirectional DC / DC converter. It is used to realize constant current charging, constant voltage charging and discharge protection of the energy storage unit according to the instructions of the intelligent control module, and at the same time monitor the voltage balance status of the individual batteries in the energy storage unit and actively balance and adjust the unbalanced batteries.

2. The uninterruptible power supply system for a control system of an air compressor according to claim 1, wherein: The main power supply module includes an EMI filter, a power factor correction circuit, and an isolated voltage regulator connected in sequence. The isolated voltage regulator adopts a flyback topology.

3. The uninterruptible power supply system for a control system of an air compressor according to claim 2, wherein: The energy storage unit's lithium iron phosphate battery pack adopts a series-parallel combination structure. The capacity of each individual battery is configured according to the rated power of the air compressor control system and the backup power supply duration. It is also equipped with a battery management unit to monitor the voltage, temperature, and internal resistance of each individual battery in real time.

4. The uninterruptible power supply system for a control system of an air compressor according to claim 3, wherein: The intelligent control module has a built-in power supply status judgment algorithm. The power supply status includes normal mains power status, abnormal mains power status, and mains power interruption status. The abnormal mains power status includes voltage fluctuation exceeding the standard, harmonic exceeding the standard, and surge. The intelligent control module triggers corresponding control strategies according to different power supply statuses.

5. A method for uninterruptible power supply for an air compressor control system, implemented based on the uninterruptible power supply system according to any one of claims 1-4, characterized in that, Includes the following steps: S1. After the intelligent control module starts, it performs self-tests on each module, including the working status of the main power supply module, backup power supply module, switching control module and status monitoring module. If a fault is found, an early warning signal will be issued immediately. If the self-test passes, it will enter the standby power supply state. S2. The main power supply module is connected to the mains power. After the EMI filter removes the grid harmonics and interference signals, the power factor is improved to above 0.98 by the power factor correction circuit. Then, the isolated voltage regulator outputs a stable voltage to power the air compressor control system. At the same time, the energy storage management module controls the bidirectional DC / DC converter to work and use the mains power to charge the energy storage unit with constant current until the energy storage unit SOC reaches 80%. Then it switches to constant voltage charging and stops charging when the SOC reaches 95%. S3. The status monitoring module continuously collects the main power supply voltage, current, harmonic content, backup power supply circuit current, SOC, temperature and single cell voltage of the energy storage unit, and transmits the monitoring data to the intelligent control module in real time. The intelligent control module analyzes the power supply status through the power supply status judgment algorithm. S4. When the intelligent control module determines that the mains power is normal, it maintains the main power supply mode. When it determines that the mains power is abnormal, such as voltage fluctuation exceeding ±10%, harmonic content exceeding the limit of GB / T 14549 standard, or surge, the control switching module prepares for switching in advance, and synchronously detects the voltage phase and frequency of the main power supply and the backup power supply. When the mains power abnormality reaches the preset threshold, it drives the bidirectional thyristor switch group to switch seamlessly to the backup power supply module, which is powered by the energy storage unit through the inverter. When the mains power is interrupted, the switching control module triggers the switching instantly to ensure uninterrupted power supply. Once the mains power is restored to normal and operates stably for 30 seconds, switch back to main power supply mode and charge the energy storage unit at the same time. S5. During the discharge process of the energy storage unit, the energy storage management module monitors the SOC in real time. When the SOC drops to 20%, a low power warning is issued, and the energy storage unit is controlled to stop discharging to avoid damage from over-discharge. During the charging process, the battery management unit monitors the voltage of individual batteries. If there is a voltage imbalance, where the voltage difference between individual batteries is ≥0.1V, the active balancing circuit is activated to adjust the charging and discharging current of individual batteries to achieve voltage balancing. The S6 intelligent control module analyzes the monitoring data in real time. If overvoltage, overcurrent, short circuit, excessive temperature of energy storage unit, or single battery failure is detected, the corresponding power supply circuit is immediately cut off, a fault warning signal is issued, and the protection mechanism is activated to ensure the safety of the system and the air compressor control system.

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