A method, apparatus, equipment and medium for smooth switching of UPS bypass to inverter power supply mode

Abstract

This invention relates to a method, apparatus, device, and medium for smooth switching from UPS bypass to inverter power supply mode. The method includes: in bypass power supply mode, controlling the inverter output voltage to accurately track the bypass mains power and maintaining its no-load standby; real-time monitoring of mains power quality and load characteristics; determining whether switching conditions are met based on the monitoring results; if met, performing a mode switching operation by linearly increasing the inverter output power at a preset first rate of change while simultaneously linearly decreasing the conduction degree of the static switch on the bypass path at a matching second rate of change; monitoring dual-path current; and determining that the switching is complete and turning off the static switch when the bypass current drops to a negligible level and the inverter has taken on the load. This achieves fast and seamless switching, significantly improving system stability and power quality.

Description

Technical Field

[0001] This invention relates to the technical field of power supply current, and in particular to a method, apparatus, equipment, and medium for smooth switching of UPS bypass to inverter power supply mode. Background Technology

[0002] Uninterruptible power supplies (UPS) are core protection devices for modern data centers, precision industrial manufacturing, and critical infrastructure. Their core function is to provide uninterrupted power to the load in the event of a mains power failure. Traditional online UPS systems typically have two main operating modes: double conversion and bypass. Double conversion mode provides a clean and stable output, but its conversion efficiency is relatively low. Bypass mode directly supplies the load with mains power, which is highly efficient but cannot filter out grid disturbances. In existing technologies, switching from the efficient bypass mode back to the high-reliability inverter mode requires a certain amount of time. During this period, the load will be powered by either the inverter's output voltage, which has not yet fully established, or interrupted mains power, potentially leading to voltage drops or momentary interruptions. This poses a risk to precision loads. This switching time has become a key bottleneck restricting further improvements in system availability and efficiency. Furthermore, maintaining precise thermal synchronization standby status for the inverter in bypass mode to achieve rapid and seamless switching is also a technical challenge.

[0003] Therefore, developing a UPS control method that can achieve rapid, seamless, and smooth switching and manage different energy sources is of urgent technical demand and significant market value in breaking the traditional contradiction between efficiency and reliability, and improving power supply quality and system economy. Summary of the Invention

[0004] The main objective of this invention is to provide a method, apparatus, device, and medium for smooth switching from UPS bypass to inverter power supply mode. By switching from the efficient bypass mode back to the high-reliability inverter mode, the inverter maintains a precise thermal synchronization standby state in the bypass mode, thereby achieving fast and seamless switching and improving system stability and power quality.

[0005] To achieve the above objectives, the present invention provides a method for smoothly switching from UPS bypass to inverter power supply mode, comprising the following steps: When the UPS is operating in bypass power supply mode, the inverter output voltage is controlled to track the voltage frequency, phase and amplitude of the bypass mains power, maintaining the inverter in an unloaded or lightly loaded standby state. Real-time monitoring of the power quality parameters of the bypass mains power and the load characteristics of the UPS; Based on the power quality parameters and the load characteristics of the UPS, determine whether the preset conditions for switching from the bypass power supply mode to the inverter power supply mode are met. If the preset conditions are met, then perform the mode switching operation. The bypass path current and the inverter output current are monitored. When the bypass path current drops below a first threshold, it is determined that the switch to inverter power supply mode has been completed, and the static switch on the bypass path is turned off.

[0006] Furthermore, the step of controlling the inverter output voltage to track the voltage frequency, phase, and amplitude of the bypass mains power when the UPS is operating in bypass power supply mode, and maintaining the inverter in an unloaded or lightly loaded standby state, includes: The real-time voltage signal of the bypass mains power is sampled and acquired; Based on the real-time voltage signal, a reference sine wave signal with the same frequency and phase as the bypass mains power is generated through a phase-locked loop; Using the reference sine wave signal as a voltage reference command, the inverter is subjected to closed-loop voltage control, driving the inverter to output an output voltage consistent with the reference sine wave signal; The amplitude difference and phase difference between the output voltage of the inverter and the bypass mains voltage are calculated in real time, and it is determined whether the amplitude difference and phase difference are continuously within the preset synchronization tolerance range.

[0007] Furthermore, the step of generating a reference sine wave signal with the same frequency and phase as the bypass mains power through a phase-locked loop based on the real-time voltage signal includes: The real-time voltage signal is subjected to coordinate transformation to obtain the direct-axis voltage component and the quadrature-axis voltage component of the real-time voltage signal in the rotating coordinate system; The quadrature-axis voltage component is used as a phase error feedback signal and input to the loop filter for processing, outputting a frequency adjustment amount; The output frequency of the voltage-controlled oscillator is adjusted according to the frequency adjustment amount to generate a phase angle synchronized with the bypass mains power. The reference sine wave signal is updated based on the synchronized phase angle and the direct-axis voltage component.

[0008] Furthermore, the step of real-time monitoring of the power quality parameters of the bypass mains power and the load characteristics of the UPS includes: The voltage signal of the bypass mains power and the current signal of the load are collected simultaneously. Based on the voltage signal, the effective voltage value, frequency value, and voltage distortion rate of the bypass mains power are calculated to obtain power quality parameters; Based on the current signal, the current power value of the load and the rate of change of the load current are calculated to obtain the load characteristic parameters.

[0009] Furthermore, the step of determining whether the preset conditions for switching from the bypass power supply mode to the inverter power supply mode are met based on the power quality parameters and the load characteristics of the UPS, and performing the mode switching operation if the preset conditions are met, includes: The effective voltage value, frequency value, and current power value of the bypass mains power obtained from real-time monitoring are acquired. The effective voltage value is compared with a preset voltage protection threshold, and / or the frequency value is compared with a preset frequency protection threshold, and / or the current power value is compared with a preset load surge threshold; When any comparison result satisfies the corresponding switching condition, it is determined that the preset condition is met, and a switching instruction is generated to start the execution mode switching operation.

[0010] Furthermore, the step of determining that the preset condition is met and generating a switching instruction to initiate the mode switching operation when any comparison result satisfies the corresponding switching condition includes: In response to the switching command, the current output power value of the inverter is obtained as a first initial value, and the current duty cycle of the static switch is obtained as a second initial value; Starting from the first initial value, and according to the preset first rate of change, calculate the sequence of the inverter output power reference value increasing over time; Starting from the second initial value, and according to the second rate of change that is compatible with the first rate of change, calculate the sequence of the static switch duty cycle decreasing over time; The calculated increasing sequence and the decreasing sequence are respectively used as real-time control commands and synchronously sent to the drive controllers of the inverter and the static switch.

[0011] Furthermore, the step of monitoring the bypass path current and the inverter output current, and determining that the switch to inverter power supply mode is completed when the bypass path current drops below a first threshold, and then turning off the static switch on the bypass path, includes: The current signal flowing through the bypass path and the current signal flowing through the output terminal of the inverter are collected in real time. The two acquired current signals are filtered and converted from analog to digital to obtain the corresponding bypass digital current value and inverter digital current value. The bypass digital current value is compared with a preset first threshold in real time, where the first threshold is 1% to 3% of the UPS rated bypass current. If the bypass digital current value remains below the first threshold for a preset duration, it is determined that the switch to inverter power supply mode has been completed. In response to the determination result of the switching completion, a shutdown command is output to control the static switch to open, thereby completing the exit of the bypass path.

[0012] The present invention also provides a device for smooth switching of UPS bypass to inverter power supply mode, comprising: The synchronous standby control module is used to control the inverter output voltage to track the voltage frequency, phase and amplitude of the bypass mains power when the UPS is operating in bypass power supply mode. The parameter monitoring module is used to monitor the power quality parameters of the bypass mains power and the load characteristics of the UPS in real time. The switching judgment module, based on power quality parameters and the load characteristics, is used to determine whether the preset conditions for switching from bypass power supply mode to inverter power supply mode are met. The switching execution module is used to perform mode switching operations when preset conditions are met. The current monitoring and completion determination module is used to monitor the bypass path current and the inverter output current. When the bypass path current decreases to a negligible level and the inverter output current has been connected to the load, it determines that the switch to inverter power supply mode is complete and outputs a shutdown signal to the static switch.

[0013] The present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the UPS bypass to inverter power supply mode smooth switching method described in any of the above claims.

[0014] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the UPS bypass to inverter power supply mode smooth switching method described in any of the above claims. Attached Figure Description

[0015] Figure 1 This is a flowchart of a method for smooth switching of UPS bypass to inverter power supply mode in one embodiment of the present invention; Figure 2 This is a structural block diagram of a UPS bypass to inverter power supply mode smooth switching device in one embodiment of the present invention; The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] Reference Figure 1This is a flowchart illustrating a method for smoothly switching a UPS bypass to inverter power supply mode proposed in this invention, comprising the following steps: S1, When the UPS is operating in bypass power supply mode, the inverter output voltage is controlled to track the voltage frequency, phase and amplitude of the bypass mains power, and the inverter is kept in a standby state of no load or light load. S2, Real-time monitoring of the power quality parameters of the bypass mains power and the load characteristics of the UPS; S3. Based on the power quality parameters and the load characteristics of the UPS, determine whether the preset conditions for switching from the bypass power supply mode to the inverter power supply mode are met. If the preset conditions are met, then perform the mode switching operation. S4. Monitor the bypass path current and the inverter output current. When the bypass path current drops below the first threshold, determine that the switch to inverter power supply mode is completed and turn off the static switch on the bypass path.

[0018] As described in step S1 above, when the UPS operates in bypass power supply mode, the inverter achieves hot backup readiness through precise synchronization control and low-power standby management. Voltage sensors collect the voltage frequency, phase, and amplitude signals of the bypass mains power in real time, and after filtering and analog-to-digital conversion, accurate electrical parameter data is obtained. Subsequently, based on a phase-locked loop (PLL) control strategy, combined with coordinate transformation, phase error feedback, and frequency adjustment mechanisms, a reference sine wave command synchronized with the mains power is generated to drive the inverter for closed-loop voltage control, ensuring that the amplitude difference between the inverter output voltage and the mains power is ≤±1% and the phase difference is ≤±1°, meeting synchronization tolerance requirements. Simultaneously, current closed-loop regulation limits the inverter output current, maintaining it in a near-zero no-load state or a light-load state ≤3% of the UPS rated output current. This avoids ineffective inverter power consumption and does not interfere with normal bypass power supply, ultimately putting the inverter in a synchronous hot backup state, ensuring rapid response and seamless transition for subsequent mode switching.

[0019] As described in step S2 above, the bypass mains power quality and UPS load characteristics are collected and analyzed in real time and synchronously to provide accurate data support for switching prediction. First, voltage signals from the bypass mains and current signals from the load are collected synchronously using voltage and current sensors. After filtering to remove electromagnetic interference, noise, and other clutter, analog-to-digital conversion is performed to obtain digital signals. Based on the digital voltage signal, the effective voltage value, frequency value, and voltage distortion rate (THD) of the bypass mains are calculated in real time to comprehensively characterize power quality. Combined with the digital current signal, the current active / reactive power value of the load is obtained through a power calculation model, and the load current change rate is obtained through a differential algorithm to accurately characterize the dynamic characteristics of the load. The entire monitoring process uses high-frequency sampling with a sampling frequency ≥1kHz to ensure data timeliness, and all parameters are uploaded to the control unit in real time, forming a continuous monitoring data stream.

[0020] As described in step S3 above, the switching conditions are determined and the switching operation is initiated based on monitoring data, achieving a smooth transition from bypass power supply to inverter power supply. First, the control unit calls upon the power quality parameters such as the effective voltage value, frequency, and voltage distortion rate collected in real time by S2, along with load characteristic parameters such as the current power and current change rate, and compares them one by one with preset thresholds such as voltage protection threshold, frequency protection threshold, and load mutation threshold. When any parameter exceeds a threshold, such as an effective voltage value fluctuation exceeding ±5%, a frequency deviation of 50Hz±0.5Hz, or a load mutation rate exceeding 20% / ms, the switching conditions are deemed met, and a switching command is generated. Subsequently, the mode switching operation is initiated: starting with the inverter's current output power, a linearly increasing power reference sequence is generated according to a preset first change rate; simultaneously, starting with the current duty cycle of the static switch, a linearly decreasing sequence is generated according to an adapted second change rate, ensuring power complementarity between the two. Both sequences are sent to the corresponding drive controllers in real time, achieving seamless power handover between the inverter and the bypass, avoiding load voltage fluctuations.

[0021] As described in step S4 above, the power transfer effect is verified by current monitoring to accurately determine the completion of the switchover and safely shut down the bypass. First, two independent current sensors are used to simultaneously collect the bypass path current and inverter output current signals. After low-pass filtering to remove high-frequency noise and analog-to-digital conversion quantization, accurate bypass digital current and inverter digital current values ​​are obtained. Then, the bypass digital current value is compared in real time with a preset first threshold (1%~3% of the UPS rated bypass current), while simultaneously verifying whether the inverter digital current value matches the load power, avoiding false triggering based on a single criterion. When the bypass digital current value remains below the first threshold for a preset duration of 50~100ms, and the inverter current stably carries the load power, the switchover is determined to be complete. Finally, the control unit outputs a shutdown command to reliably disconnect the static switch on the bypass path, ensuring the bypass path is completely deactivated, avoiding the risk of simultaneous conduction of two power supplies, and concluding the stable operation of the inverter power supply mode without voltage surges or power interruptions throughout the process.

[0022] In one embodiment, step S1, which controls the inverter output voltage to track the voltage frequency, phase, and amplitude of the bypass mains power when the UPS is operating in bypass power supply mode, and maintains the inverter in an unloaded or lightly loaded standby state, includes: S11, Signal Acquisition and Preprocessing; S12, Synchronization reference generation; S13, Inverter voltage closed-loop control; S14, low-power standby management; S15, Synchronization status verification.

[0023] In practical implementation, the voltage sensor continuously acquires the voltage signal of the bypass mains power. A voltage Hall sensor with an accuracy class of 0.2 is selected, and the acquisition range covers the mains power fluctuation range of 220V ± 20%. The acquired analog signal is first processed by a low-pass filter with a cutoff frequency of 100Hz to filter out high-frequency noise and electromagnetic interference in the power grid. Then, a 16-bit analog-to-digital converter is used to quantize the analog signal into a digital signal at a sampling frequency of 1kHz, accurately extracting core parameters such as the 50Hz frequency of the bypass mains power, the 0° initial phase, and the 220V RMS value. Based on the extracted mains power parameters, the phase-locked loop control process is started, and coordinate transformation operations are performed on the digital voltage signal to decompose it into the direct-axis voltage component of 220V and the quadrature-axis voltage component of 0V in the rotating coordinate system. The quadrature-axis voltage component is directly input as the phase error feedback signal to a loop filter with proportional-integral coefficients of 0.5 and 0.1, respectively. After adjustment, it outputs a frequency adjustment of ±0.1Hz. This adjustment is applied to the voltage-controlled oscillator (VCO) in real time, dynamically adjusting the oscillator's output frequency to generate a phase angle completely synchronized with the bypass mains power. The phase data is updated every 10ms. Combining the synchronization phase angle and the direct-axis voltage component, a reference sine wave signal consistent with the mains parameters is constructed and updated as a reference command for the inverter's voltage output. After receiving the reference sine wave command, the inverter initiates closed-loop voltage control. A drive signal is generated using pulse width modulation (PWM) technology with a carrier frequency of 10kHz to control the on / off timing of the IGBT power switching devices inside the inverter. This drives the inverter's output voltage to accurately track the reference sine wave signal, ensuring that the output voltage maintains a frequency of 50Hz consistent with the bypass mains power, a phase deviation of no more than ±1°, and an amplitude stable within the range of 220V±1%, achieving complete matching of the three parameters. While controlling voltage synchronization, a current closed-loop regulation mechanism is initiated. A closed-loop Hall current sensor is used to monitor the inverter's output current in real time. The monitored current signal is compared with a preset threshold. If the UPS rated output current is 100A, the current threshold is set to be close to zero under no-load conditions and 3A under light-load conditions. Based on the comparison results, the duty cycle of the inverter's PWM drive signal is dynamically adjusted to limit the output current to be maintained in a near-zero no-load state or a light-load state not exceeding 3A. The synchronization status monitoring module calculates the amplitude difference and phase difference between the inverter output voltage and the bypass mains voltage in real time. The preset amplitude difference tolerance is ±1% and the phase difference tolerance is ±1°. When the amplitude difference reaches 1.2% or the phase difference reaches 1.5°, the deviation signal is immediately fed back to the phase-locked loop and the inverter drive control unit. By adjusting the proportional coefficient of the phase-locked loop to 0.6 and increasing the update frequency of the inverter drive signal to 2kHz, the deviation is corrected in real time to ensure that the inverter is always in a hot backup standby state that is precisely synchronized with the mains power.

[0024] In one embodiment, step S2, which involves real-time monitoring of the power quality parameters of the bypass mains power and the load characteristics of the UPS, includes: S21, synchronous signal acquisition; S22, Signal preprocessing; S23, Calculation of power quality parameters; S24, Calculation of load characteristic parameters; S25, monitoring data upload.

[0025] In practical implementation, the voltage Hall sensor and closed-loop current sensor synchronously acquire the bypass mains voltage signal and the UPS load current signal, respectively. The acquisition system uses a uniform sampling frequency of 1kHz to ensure that the voltage and current signals are perfectly aligned on the time axis, avoiding parameter calculation errors caused by timing deviations. The voltage sensor's acquisition range covers the 220V±20% mains voltage fluctuation range, while the current sensor's range is adapted to 0-120% of the UPS's rated output current, meeting the monitoring needs under different load conditions. The acquired voltage and current analog signals first enter the signal preprocessing unit. The voltage signal passes through a low-pass filter circuit with a cutoff frequency of 500Hz to filter out high-frequency noise generated by industrial interference; the current signal passes through an RC filter network to suppress noise interference caused by electromagnetic coupling. The filtered clean analog signal is sent to a 16-bit analog-to-digital converter module to quantize the continuous analog quantity into a discrete digital signal, with the quantization error controlled within ±0.0015%. Based on the preprocessed digital voltage signal, the effective value of the bypass mains voltage is calculated in real time using the root mean square (RMS) algorithm. Taking a standard mains voltage of 220V as an example, voltage sampling values ​​for 20 consecutive cycles are collected, and the real-time effective value is obtained through RMS calculation, ensuring that the fluctuation range is controlled within 220V ± 1%. The voltage frequency is calculated using the zero-crossing detection method. By identifying the time interval between two adjacent zero-crossing points, the mains frequency is calculated. When a frequency deviation of 50Hz ± 0.5Hz is detected, it is immediately marked as an abnormal fluctuation. The voltage signal is analyzed for harmonics using Fast Fourier Transform (FFT) to decompose the fundamental frequency and each harmonic component. The voltage distortion rate is calculated by the ratio of the total effective value of harmonics to the effective value of the fundamental frequency. Under typical operating conditions, the mains distortion rate should be less than 3%. When it exceeds 5%, a power quality warning is triggered. Combining the digital voltage signal and the synchronously acquired digital current signal, the current active and reactive power of the load are calculated using an instantaneous power integral algorithm. Assuming a certain instantaneous effective voltage value of 220V, an effective current value of 50A, and a power factor of 0.9, the calculated active power is 9.9kW and the reactive power is 4.8kvar. The load current change rate is calculated using a sliding window differential method. A 10ms time window is selected, and the change rate is obtained by the ratio of the current difference between the two windows to the time. When the load suddenly increases from no-load to rated load, the current change rate can reach 30A / ms. A load change is defined as exceeding the preset threshold of 20A / ms.

[0026] All calculated power quality parameters and load characteristic parameters are uploaded to the UPS main control unit in real time via a high-speed SPI bus. The data transmission rate is set to 1Mbps to ensure that all parameters are updated every 100ms, forming a continuous and complete monitoring data stream. The control unit stores the received data in a circular buffer, retaining the historical data of the most recent 10 seconds, providing real-time quantitative basis for switching condition judgment.

[0027] In one embodiment, step S3, which determines whether the preset conditions for switching from the bypass power supply mode to the inverter power supply mode are met based on the power quality parameters and the load characteristics of the UPS, and if the preset conditions are met, then the mode switching operation is performed, includes: S31, parameter call; S32, threshold comparison; S33, Condition Determination; S34, switch parameter configuration; S35, instruction generation and issuance.

[0028] In practical implementation, the UPS main control unit retrieves real-time monitoring data stored in the circular buffer during step S2 via its internal data bus. This data covers core parameters such as the effective voltage, frequency, and voltage distortion rate of the bypass mains power, as well as the current active power, reactive power, and current change rate of the load. Data retrieval follows a synchronous update rhythm of once every 100ms, ensuring that the parameters used are fully matched with the current power grid and load conditions, providing timely support for switching decisions. The control unit has a built-in preset threshold library, setting clear safe operating ranges for different parameters. The effective voltage threshold is set to 220V±5%, i.e., an upper limit of 231V and a lower limit of 209V; the frequency threshold is set to 50Hz±0.5Hz, covering the range of 49.5Hz to 50.5Hz; the voltage distortion rate threshold is set to 5%; the load current change rate threshold is set to 20A / ms; and the load power threshold is dynamically adjusted according to the UPS rated power. For example, if the UPS rated power is 10kW, the load power threshold is set to 11kW. The control unit compares the parameters retrieved in real time with the corresponding thresholds one by one. The comparison process uses parallel computing logic to ensure the efficiency of the judgment. For example, if the effective voltage value retrieved at a certain moment is 235V, which exceeds the upper limit threshold of 231V; or the load current change rate reaches 25A / ms, which exceeds the set standard of 20A / ms; or the voltage distortion rate is detected as 6.2%, which exceeds the threshold limit of 5%, the switching conditions are determined to be met if any of these conditions occur. After the judgment result is generated, the control unit immediately marks the switching status as "ready" and locks the parameter data at the current moment to avoid subsequent data fluctuations affecting the switching decision. During the parameter configuration phase, the control unit first acquires the initial values ​​of the current inverter output power and the static switch duty cycle. If the inverter is currently in a light-load standby state, the initial output power is 0.3kW, and the initial static switch duty cycle is 98%. The first rate of change is set based on the load voltage fluctuation tolerance of ≤±2%, and combined with the current load power of 9.9kW, it is set to 0.5kW / ms. The second rate of change satisfies the power complementarity relationship with the first rate of change, that is, for every 0.5kW increase in inverter power, the static switch correspondingly reduces its power percentage by the same amount, which is calculated and set to 4.9% / ms. Based on the initial values ​​and the rate of change, the control unit generates two sets of continuous control sequences. The inverter output power reference value sequence starts at 0.3kW and increases at 0.5kW / ms, successively reaching 0.8kW, 1.3kW, 1.8kW, etc., until it reaches the current load power of 9.9kW. The static switch duty cycle sequence starts at 98% and decreases at 4.9% / ms, successively reaching 93.1%, 88.2%, 83.3%, etc., until it drops to 0%. Both sequences are updated at a frequency of 1kHz to ensure the continuity of power handover.The control unit sends control sequences through dual independent drive channels. The inverter drive channel uses a CAN bus to transmit the power reference value sequence, while the static switch drive channel uses a PWM signal to transmit the duty cycle sequence. The transmission delay is controlled within 1ms. After receiving the sequence, the inverter adjusts the drive signals of the internal IGBT switching devices in real time to dynamically increase the output power. The static switch responds synchronously and gradually reduces the conduction duty cycle to achieve a smooth transfer of bypass power to inverter power. Throughout the process, the load voltage fluctuation is always controlled within ±2%, without any impactful changes.

[0029] In one embodiment, step S4, which involves monitoring the bypass path current and the inverter output current, determining that the switch to inverter power supply mode is complete when the bypass path current drops below a first threshold, and turning off the static switch on the bypass path, includes: S41, synchronously acquires dual-channel current signals; S42, dual-channel signal preprocessing and quantization; S43, threshold comparison and current verification; S44, Determine if the switch is complete; S45, disconnect the bypass static switch.

[0030] In practical implementation, two sets of closed-loop Hall current sensors with an accuracy class of 0.1 are selected and deployed at the bypass path and inverter output terminal respectively to synchronously acquire two current signals. The sensor range covers 0-150% of the UPS rated output current, and the sampling frequency is kept consistent with step S2 at 1kHz to ensure that the current data is synchronized with the previous monitoring parameters. Taking a UPS rated output current of 100A as an example, the sensor can accurately capture current changes within the range of 0.1A to 150A, meeting the monitoring requirements of full-condition operation from no-load to full-load. The acquired two analog current signals enter the signal processing unit. The bypass current signal passes through a low-pass filter circuit with a cutoff frequency of 200Hz to filter out the switching noise generated when the static switch is turned on; the inverter output current signal passes through an active filter circuit to suppress the high-frequency ripple caused by the switching of power devices. The filtered clean signal is sent to a 16-bit analog-to-digital converter module, with the quantization error controlled within ±0.0015%, converting the analog signal into accurate bypass digital current values ​​and inverter digital current values, and completing a data update every 1ms. The control unit invokes a preset first threshold, which is set to 1%-3% of the UPS's rated bypass current. For a UPS with a rated current of 100A, the first threshold ranges from 1A to 3A, with 1A for highly sensitive load scenarios and 3A for ordinary industrial load scenarios. The control unit continuously compares the real-time updated bypass digital current value with the first threshold, while simultaneously verifying whether the inverter digital current value matches the current power of the load. If the current active power of the load is 9.9kW and the voltage is 220V, the corresponding load current is approximately 45A. When the inverter digital current value stabilizes in the range of 44.8A to 45.2A, it is determined that the inverter has reliably undertaken the load power. A preset duration of 80ms is set to avoid false judgments caused by instantaneous current fluctuations. When the bypass digital current value drops below 1A and remains below 1A for 80ms, and the inverter digital current value remains stable within the range corresponding to the load current, the control unit determines that the switch to inverter power supply mode has been completed. If the bypass digital current value rebounds above 1A during this period, the timing restarts to ensure the reliability of the judgment result. After the switching completion determination is generated, the control unit outputs a high-level shutdown command through the optocoupler isolation circuit. The command transmission delay is controlled within 2ms. The command acts on the bidirectional thyristor static switch on the bypass path, triggering the switching device to turn off. After the static switch turns off, the control unit continuously monitors the bypass path current. When the current value drops below 0.1A, it indicates that the bypass path has been completely disconnected. At this time, the inverter independently supplies power to the load. The entire switching process is completed without voltage surges or power interruptions, ensuring stable operation of the load.

[0031] Reference Figure 2 Here is a structural block diagram of a UPS bypass to inverter power supply mode smooth switching method according to an embodiment of the present invention, including: The synchronous standby control module is used to control the inverter output voltage to track the voltage frequency, phase and amplitude of the bypass mains power when the UPS is operating in bypass power supply mode. The parameter monitoring module is used to monitor the power quality parameters of the bypass mains power and the load characteristics of the UPS in real time. The switching judgment module, based on power quality parameters and the load characteristics, is used to determine whether the preset conditions for switching from bypass power supply mode to inverter power supply mode are met. The switching execution module is used to perform mode switching operations when preset conditions are met. The current monitoring and completion determination module is used to monitor the bypass path current and the inverter output current. When the bypass path current decreases to a negligible level and the inverter output current has been connected to the load, it determines that the switch to inverter power supply mode is complete and outputs a shutdown signal to the static switch.

[0032] For the specific implementation of each module in the above device example, please refer to the above method embodiments, which will not be repeated here.

[0033] In summary, this invention achieves a smooth and uninterrupted mode transition through a four-step closed loop: "synchronous standby - parameter monitoring - switching execution - final confirmation". During implementation, the UPS operates in bypass power supply mode, first initiating synchronous control. Voltage sensors collect the mains signal, which is then filtered and quantized. Through phase-locked loop coordinate transformation and phase error feedback, a reference command for synchronized frequency and phase is generated, driving the inverter output voltage to precisely match the mains power. Simultaneously, the output current is limited to a light load state (no load or no more than 3% of the rated current) to ensure hot backup readiness. Simultaneously, mains and load parameter monitoring is initiated. Dual sensors synchronously collect voltage and current signals at a 1kHz frequency. After filtering and analog-to-digital conversion, parameters such as the effective voltage value, frequency, distortion rate, load power, and current change rate are calculated, forming a continuous data stream to support decision-making. When any threshold is detected, such as voltage exceeding 220V±5%, frequency deviating from 50Hz±0.5%, or load change rate exceeding 20A / ms, a switching operation is triggered. The change rate is set according to the power complementarity principle, generating a sequence of increasing inverter power and decreasing static switch duty cycle to achieve smooth power transfer. During switching, dual-path current is monitored simultaneously, reducing the bypass current of the 100A rated current UPS to 1-3A. When the threshold is reached and maintained for 80ms, and the inverter current stably carries the load power, the switching is considered complete, and the static switch is reliably disconnected. Throughout the process, through precise synchronization, dynamic adjustment, and rigorous verification, the load voltage fluctuation is ensured to be ≤±2%, with no power interruption or impact, making it suitable for general industrial and highly sensitive load scenarios.

[0034] An embodiment of the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the above-described method. It is understood that the computer-readable storage medium in this embodiment can be a volatile readable storage medium or a non-volatile readable storage medium.

[0035] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the present invention and embodiments can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual-rate SDRAM (SSRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), Rambus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM, etc.

[0036] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, apparatus, article, or method that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, apparatus, article, or method. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, apparatus, article, or method that includes that element.

[0037] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for smoothly switching from UPS bypass to inverter power supply mode, characterized in that, Includes the following steps: When the UPS is operating in bypass power supply mode, the inverter output voltage is controlled to track the voltage frequency, phase and amplitude of the bypass mains power, maintaining the inverter in an unloaded or lightly loaded standby state. Real-time monitoring of the power quality parameters of the bypass mains power and the load characteristics of the UPS; Based on the power quality parameters and the load characteristics of the UPS, determine whether the preset conditions for switching from the bypass power supply mode to the inverter power supply mode are met. If the preset conditions are met, then perform the mode switching operation. The bypass path current and the inverter output current are monitored. When the bypass path current drops below a first threshold, it is determined that the switch to inverter power supply mode has been completed, and the static switch on the bypass path is turned off.

2. The method for smooth switching of UPS bypass to inverter power supply mode according to claim 1, characterized in that, The step of controlling the inverter output voltage to track the voltage frequency, phase, and amplitude of the bypass mains power when the UPS is operating in bypass power supply mode, and maintaining the inverter in an unloaded or lightly loaded standby state, includes: The real-time voltage signal of the bypass mains power is sampled and acquired; Based on the real-time voltage signal, a reference sine wave signal with the same frequency and phase as the bypass mains power is generated through a phase-locked loop; Using the reference sine wave signal as a voltage reference command, the inverter is subjected to closed-loop voltage control, driving the inverter to output an output voltage consistent with the reference sine wave signal. The amplitude difference and phase difference between the output voltage of the inverter and the bypass mains voltage are calculated in real time, and it is determined whether the amplitude difference and phase difference are continuously within the preset synchronization tolerance range.

3. The method for smooth switching of UPS bypass to inverter power supply mode according to claim 2, characterized in that, The step of generating a reference sine wave signal with the same frequency and phase as the bypass mains power through a phase-locked loop based on the real-time voltage signal includes: The real-time voltage signal is subjected to coordinate transformation to obtain the direct-axis voltage component and the quadrature-axis voltage component of the real-time voltage signal in the rotating coordinate system; The quadrature-axis voltage component is used as a phase error feedback signal and input to the loop filter for processing, outputting a frequency adjustment amount; The output frequency of the voltage-controlled oscillator is adjusted according to the frequency adjustment amount to generate a phase angle synchronized with the bypass mains power. The reference sine wave signal is updated based on the synchronized phase angle and the direct-axis voltage component.

4. The method for smooth switching of UPS bypass to inverter power supply mode according to claim 1, characterized in that, The step of real-time monitoring of the power quality parameters of the bypass mains power and the load characteristics of the UPS includes: The voltage signal of the bypass mains power and the current signal of the load are collected simultaneously. Based on the voltage signal, the effective voltage value, frequency value, and voltage distortion rate of the bypass mains power are calculated to obtain power quality parameters; Based on the current signal, the current power value of the load and the rate of change of the load current are calculated to obtain the load characteristic parameters.

5. The method for smooth switching of UPS bypass to inverter power supply mode according to claim 1, characterized in that, The step of determining whether the preset conditions for switching from the bypass power supply mode to the inverter power supply mode are met based on the power quality parameters and the load characteristics of the UPS, and performing the mode switching operation if the preset conditions are met, includes: The effective voltage value, frequency value, and current power value of the bypass mains power obtained from real-time monitoring are acquired. The effective voltage value is compared with a preset voltage protection threshold, and / or the frequency value is compared with a preset frequency protection threshold, and / or the current power value is compared with a preset load surge threshold; When any comparison result satisfies the corresponding switching condition, it is determined that the preset condition is met, and a switching instruction is generated to start the execution mode switching operation.

6. The method for smooth switching of UPS bypass to inverter power supply mode according to claim 5, characterized in that, The step of determining that the preset condition is met and generating a switching instruction to initiate the mode switching operation when any comparison result satisfies the corresponding switching condition includes: In response to the switching command, the current output power value of the inverter is obtained as a first initial value, and the current duty cycle of the static switch is obtained as a second initial value; Starting from the first initial value, and according to the preset first rate of change, calculate the sequence of the inverter output power reference value increasing over time; Starting from the second initial value, and according to the second rate of change that is compatible with the first rate of change, calculate the sequence of the static switch duty cycle decreasing over time; The calculated increasing sequence and the decreasing sequence are respectively used as real-time control commands and synchronously sent to the drive controllers of the inverter and the static switch.

7. The method for smooth switching of UPS bypass to inverter power supply mode according to claim 1, characterized in that, The steps of monitoring the bypass path current and the inverter output current, determining that the switch to inverter power supply mode is complete when the bypass path current drops below a first threshold, and turning off the static switch on the bypass path, include: The current signal flowing through the bypass path and the current signal flowing through the output terminal of the inverter are collected in real time. The two acquired current signals are filtered and converted from analog to digital to obtain the corresponding bypass digital current value and inverter digital current value. The bypass digital current value is compared with a preset first threshold in real time, where the first threshold is 1% to 3% of the UPS rated bypass current. If the bypass digital current value remains below the first threshold for a preset duration, it is determined that the switch to inverter power supply mode has been completed. In response to the determination result of the switching completion, a shutdown command is output to control the static switch to open, thereby completing the exit of the bypass path.

8. A device for smooth switching between UPS bypass and inverter power supply modes, characterized in that, include: The synchronous standby control module is used to control the inverter output voltage to track the voltage frequency, phase and amplitude of the bypass mains power when the UPS is operating in bypass power supply mode. The parameter monitoring module is used to monitor the power quality parameters of the bypass mains power and the load characteristics of the UPS in real time. The switching judgment module, based on power quality parameters and the load characteristics, is used to determine whether the preset conditions for switching from bypass power supply mode to inverter power supply mode are met. The switching execution module is used to perform mode switching operations when preset conditions are met. The current monitoring and completion determination module is used to monitor the bypass path current and the inverter output current. When the bypass path current decreases to a negligible level and the inverter output current has been connected to the load, it determines that the switch to inverter power supply mode is complete and outputs a shutdown signal to the static switch.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the UPS bypass to inverter power supply mode smooth switching method as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the UPS bypass to inverter power supply mode smooth switching method as described in any one of claims 1 to 7.

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