Intelligent switching and energy recovery system for elevator emergency power supply

Abstract

The application belongs to the field of elevator control and power electronics technology, and particularly relates to an elevator emergency power intelligent switching and energy recovery system, which comprises a power grid detection module, a capacitor energy storage module, a bidirectional DC / DC converter, an inverter feedback module and an intelligent switching controller; the power grid detection module monitors the power grid state in real time; the capacitor energy storage module is connected in parallel with a DC bus of a traction machine frequency converter, stores braking regenerative energy and serves as an emergency power supply; the bidirectional DC / DC converter realizes bidirectional energy flow between the DC bus and the energy storage module; the intelligent switching controller intelligently controls the switching between four operation modes of energy recovery charging, energy storage discharging assistance, inverter feedback and emergency power supply according to the power grid state, the state of charge of the energy storage module and the elevator operation state; the problems of high cost, low reliability of the existing elevator emergency power supply device and high system complexity caused by the independence of the energy recovery device and the emergency power supply are solved.

Description

Technical Field

[0001] This invention belongs to the field of elevator control and power electronics technology, specifically an intelligent switching and energy recovery system for elevator emergency power supply. Background Technology

[0002] With the acceleration of urbanization, elevators, as the core vertical transportation equipment in high-rise buildings, are seeing a continuous increase in their number. Two key issues urgently need to be addressed during elevator operation: first, the safety hazard of passengers being trapped during sudden power outages; and second, the effective recovery and utilization of regenerative energy during elevator braking.

[0003] Most existing elevator systems lack automatic emergency functions when encountering power outages. The elevator will lose power and mechanically engage the brakes, trapping passengers and posing a serious psychological and even physiological hazard to vulnerable groups (the elderly, the frail, those with heart conditions, pregnant women, etc.). Existing elevator power outage emergency devices generally employ a "no-use-under-normal-times-but-take-control-during-power-outages" approach. This involves configuring a separate, small elevator control system to provide all functions during a power outage, including driving the main motor, logic control, brakes, door operator, and lighting control. This approach is not only costly but also requires extensive modifications to the existing system's electrical connections (typically dozens), significantly reducing system reliability and severely hindering the widespread adoption of elevator emergency devices.

[0004] In terms of energy recovery, elevator traction machines generate a significant amount of regenerative energy during braking (such as when the car is lightly loaded ascending or heavily loaded descending). Traditionally, this energy is dissipated as heat through braking resistors, resulting in energy waste and increased machine room temperature, thus increasing air conditioning system energy consumption. According to research, energy feedback devices can recover over 95% of this regenerative energy. In recent years, supercapacitor-based energy recovery solutions have emerged, utilizing the rapid charging and discharging characteristics of supercapacitors to effectively absorb the regenerative energy generated by traction machine braking and release it during elevator operation to provide auxiliary power. Some solutions also attempt to combine energy feedback with emergency power supply functions, such as through the integrated design of inverter feedback circuits and supercapacitor energy storage units, simultaneously achieving energy-saving operation and safety assurance during grid anomalies.

[0005] However, existing integrated solutions still have the following shortcomings: First, the switching logic between emergency power supply switching and energy recovery mode is relatively simple, failing to fully integrate multi-dimensional information such as the state of charge of the energy storage unit, the elevator operating status, and the grid status for intelligent decision-making, which may lead to energy loss or untimely emergency response during the switching process; Second, most energy recovery strategies are based on fixed threshold control, lacking dynamic adaptation to elevator operating conditions, and there is still room for improvement in energy utilization efficiency; Third, the charging and discharging management and health status monitoring of the energy storage unit are relatively crude, affecting the long-term reliability of the system.

[0006] Based on the above analysis, there is an urgent need to develop an integrated system that can achieve intelligent and seamless switching of emergency power and efficient recovery of regenerative energy, so as to balance the safety of elevator operation with the needs of energy conservation and consumption reduction. Summary of the Invention

[0007] The purpose of this application is to address the shortcomings of existing technologies by designing an intelligent switching and energy recovery system for elevator emergency power supplies using a grid detection module, a capacitor energy storage module, and an intelligent switching controller. This system solves the problems of high cost, low reliability, and high system complexity caused by the independence of the energy recovery device and the emergency power supply in existing elevator emergency power supply devices.

[0008] To achieve the above objectives, the following technical solution is adopted: An intelligent emergency power switching and energy recovery system for elevators includes: The power grid detection module is used to monitor the voltage amplitude, frequency and phase of the three-phase power grid in real time, determine the power supply status of the power grid, and output a power grid abnormality signal when a power grid abnormality is detected. The capacitor energy storage module is connected in parallel with the DC bus of the traction machine frequency converter to store the regenerative energy generated during the braking process of the traction machine, and to supply power to the elevator system as an emergency power source when the power grid is abnormal; A bidirectional DC / DC converter is connected between the DC bus of the traction machine frequency converter and the capacitor energy storage module to realize bidirectional energy flow between the DC bus of the traction machine frequency converter and the capacitor energy storage module. The inverter feedback module has its input end connected to the DC bus of the traction machine frequency converter and its output end connected to the power grid or the AC bus inside the building. It is used to feed back excess regenerative energy to the power grid with a unity power factor. The intelligent switching controller is connected to the power grid detection module, the capacitor energy storage module, the bidirectional DC / DC converter, the inverter feedback module, and the elevator main controller. It is used to switch the operating mode according to the status of the power grid detection module, the state of charge of the capacitor energy storage module, and the elevator operating status.

[0009] Preferably, the intelligent switching controller includes: The status acquisition unit is used to acquire real-time power grid status signals, the state of charge and health status of the capacitor energy storage module, and elevator operation status signals. The mode decision unit has a built-in fuzzy reasoning algorithm model, which calculates the current operating mode to be entered based on the multi-dimensional information provided by the state acquisition unit. The switching execution unit sends control commands to the bidirectional DC / DC converter and inverter feedback module based on the decision results of the mode decision unit, and controls the seamless switching between the power grid and the emergency power supply.

[0010] Preferably, the mode decision unit adopts an intelligent decision-making algorithm based on deep reinforcement learning, using the health status of the capacitor energy storage module, the current electricity price period, and the predicted value of the elevator load as the state space, the operation mode selection and charging / discharging power as the action space, and constructing a reward function based on comprehensive benefits, and obtaining the optimal decision model through offline training.

[0011] Preferably, the following operating modes are also included: In the energy recovery charging mode, when the power grid is normal, the elevator traction machine is in the power generation state, and the state of charge of the capacitor energy storage module is lower than the preset charging upper limit threshold, the bidirectional DC / DC converter is controlled to store the regenerated electrical energy on the DC bus into the capacitor energy storage module. In the energy storage discharge auxiliary mode, when the power grid is normal, the elevator traction machine is in motor mode, and the state of charge of the capacitor energy storage module is higher than the preset discharge lower limit threshold, the bidirectional DC / DC converter is controlled to release the energy of the energy storage module to the traction machine frequency converter. In inverter feedback mode, when the grid is normal and the voltage of the capacitor energy storage module reaches the preset upper limit threshold, the inverter feedback module is activated to feed excess regenerated energy back to the grid. In emergency power supply mode, when the power grid detection module detects a power outage or abnormal voltage, it cuts off the power grid input and the capacitor energy storage module provides emergency power to the elevator system, controlling the traction machine to move the car to the nearest leveling position.

[0012] Preferably, the power grid detection module is based on software phase-locked loop technology with rotating coordinate transformation and model reference adaptation, which can complete power outage detection within half a power grid cycle.

[0013] Preferably, the capacitor energy storage module includes an energy storage array composed of multiple capacitor cells connected in series and a status monitoring unit for monitoring the voltage, current and temperature of the energy storage module; the status monitoring unit is also used to estimate the health status of the energy storage module in real time, and the intelligent switching controller dynamically adjusts the upper limit of the charge and discharge rate according to the health status value.

[0014] Preferably, the bidirectional DC / DC converter adopts fully digital PWM control technology.

[0015] Preferably, the inverter feedback module is based on the active inverter principle, tracks grid synchronization through phase-locked loop technology, determines the phase angle and amplitude of the inverter output voltage through the phase amplitude control principle, and feeds back electrical energy to the grid with unity power factor.

[0016] Preferably, it includes an energy discharge protection module connected in parallel with a capacitor energy storage module, used to discharge residual electrical energy in the elevator emergency power intelligent switching and energy recovery system in a controlled manner when the system is shut down for a long period of time or under maintenance.

[0017] Preferably, it also includes a communication interface module for data interaction with the building energy management system or remote operation and maintenance platform, uploading the operation data, energy consumption statistics and fault alarm information of the entire elevator emergency power intelligent switching and energy recovery system.

[0018] Compared with the prior art, the beneficial effects of the technical solution of this application are: 1. The emergency power intelligent switching function and regenerative energy recovery function are integrated into the same system. The multiplexed inverter circuit design reduces hardware costs and device size. At the same time, since the system wiring remains almost unchanged, the reliability of the original elevator system is not affected.

[0019] 2. By introducing fuzzy reasoning and deep reinforcement learning decision-making algorithms based on multi-dimensional information fusion, the system can dynamically optimize its operation mode according to various factors such as grid status, energy storage status, elevator operating conditions, and electricity price periods. This enables a leap from "fixed threshold control" to "adaptive intelligent control," significantly improving energy utilization efficiency and emergency response timeliness. Detailed Implementation

[0020] An intelligent emergency power switching and energy recovery system for elevators includes: The power grid detection module is used to monitor the voltage amplitude, frequency and phase of the three-phase power grid in real time. It uses software phase-locked loop technology based on rotating coordinate transformation and model reference adaptation to determine the power grid supply status. When a power grid abnormality is detected, a power grid abnormality signal is output. For example, when the power grid voltage drops below 85% of the rated value or the power is completely cut off, a power grid abnormality signal is output to the intelligent switching controller within 10ms (half a power grid cycle).

[0021] The capacitor energy storage module is connected in parallel with the DC bus of the traction machine frequency converter to store the regenerative energy generated during the braking process of the traction machine, and to supply power to the elevator system as an emergency power source when the power grid is abnormal; A bidirectional DC / DC converter is connected between the DC bus of the traction machine frequency converter and the capacitor energy storage module to realize bidirectional energy flow between the DC bus of the traction machine frequency converter and the capacitor energy storage module. The inverter feedback module has its input end connected to the DC bus of the traction machine frequency converter and its output end connected to the power grid or the AC bus inside the building. It is used to feed back excess regenerative energy to the power grid with a unity power factor. The intelligent switching controller is connected to the power grid detection module, the capacitor energy storage module, the bidirectional DC / DC converter, the inverter feedback module, and the elevator main controller. It is used to switch the operating mode according to the status of the power grid detection module, the state of charge of the capacitor energy storage module, and the elevator operating status.

[0022] As a preferred embodiment, the intelligent switching controller includes: The status acquisition unit is used to acquire real-time power grid status signals, the state of charge and health status of the capacitor energy storage module, and elevator operation status signals. The mode decision unit has a built-in fuzzy reasoning algorithm model, which calculates the current operating mode to be entered based on the multi-dimensional information provided by the state acquisition unit. The switching execution unit sends control commands to the bidirectional DC / DC converter and inverter feedback module based on the decision results of the mode decision unit, and controls the seamless switching between the power grid and the emergency power supply.

[0023] As a preferred approach, the mode decision unit employs an intelligent decision-making algorithm based on deep reinforcement learning. It uses the health status of the capacitor energy storage module, the current electricity price period, and the predicted elevator load as the state space, the operation mode selection and charging / discharging power as the action space, and constructs a reward function based on comprehensive benefits. The optimal decision model is obtained through offline training.

[0024] As a preferred approach, the following operating modes are also included: In the energy recovery charging mode, when the power grid is normal, the elevator traction machine is in the power generation state, and the state of charge of the capacitor energy storage module is lower than the preset charging upper limit threshold, the bidirectional DC / DC converter is controlled to store the regenerated electrical energy on the DC bus into the capacitor energy storage module. In the energy storage discharge auxiliary mode, when the power grid is normal, the elevator traction machine is in motor mode, and the state of charge of the capacitor energy storage module is higher than the preset discharge lower limit threshold, the bidirectional DC / DC converter is controlled to release the energy of the energy storage module to the traction machine frequency converter. In inverter feedback mode, when the grid is normal and the voltage of the capacitor energy storage module reaches the preset upper limit threshold, the inverter feedback module is activated to feed excess regenerated energy back to the grid. In emergency power supply mode, when the power grid detection module detects a power outage or abnormal voltage, it cuts off the power grid input and the capacitor energy storage module provides emergency power to the elevator system, controlling the traction machine to move the car to the nearest leveling position.

[0025] As a preferred approach, the power grid detection module is based on software phase-locked loop technology with rotating coordinate transformation and model reference adaptation, which can complete power outage detection within half a power grid cycle.

[0026] In a preferred embodiment, the capacitor energy storage module includes an energy storage array composed of multiple capacitor cells connected in series, and a status monitoring unit for monitoring the voltage, current, and temperature of the energy storage module. The status monitoring unit also estimates the health status of the energy storage module in real time, and the intelligent switching controller dynamically adjusts the upper limit of the charge / discharge rate based on the health status value. In practical applications, the rated voltage range of the capacitor energy storage module is 200V to 800V, which can be configured according to the DC bus voltage level of the elevator traction machine inverter. The capacitor energy storage module has built-in voltage, current, and temperature sensors, which report the terminal voltage, charge / discharge current, and operating temperature of the capacitor energy storage module to the intelligent switching controller in real time.

[0027] As a preferred approach, the bidirectional DC / DC converter employs fully digital PWM control technology. It supports bidirectional energy flow, boasts an energy conversion efficiency exceeding 95%, and a millisecond-level response speed, meeting the rapid charging and discharging requirements of the capacitor energy storage module. In buck mode, it converts the high-voltage power from the traction machine inverter's DC bus to low voltage to charge the capacitor energy storage module; in boost mode, it boosts the low-voltage power from the capacitor energy storage module and feeds it back to the traction machine inverter's DC bus.

[0028] As a preferred approach, the inverter feedback module is based on the active inverter principle, tracks grid synchronization through phase-locked loop technology, determines the phase angle and amplitude of the inverter output voltage through the phase amplitude control principle, and feeds back electrical energy to the grid with unity power factor.

[0029] As a preferred approach, an energy discharge protection module is included, connected in parallel with a capacitor energy storage module, to discharge residual electrical energy in the elevator emergency power intelligent switching and energy recovery system in a controlled manner when the system is shut down for a long period of time or under maintenance.

[0030] As a preferred approach, a communication interface module is also included, which is used to interact with the building energy management system or remote operation and maintenance platform to upload the operation data, energy consumption statistics and fault alarm information of the entire elevator emergency power intelligent switching and energy recovery system.

[0031] In the entire elevator emergency power intelligent switching and energy recovery system, when the power grid is normal, the intelligent switching controller makes mode decisions based on the traction machine's operating status and the SOC value of the capacitor energy storage module: when the traction machine is in generator mode and the SOC is below the upper charging threshold (e.g., SOC < 90%), it enters the energy recovery charging mode; when the traction machine is in motor mode and the SOC is above the lower discharge threshold (e.g., SOC > 30%), it enters the energy storage discharge auxiliary mode; when the SOC reaches the upper threshold, it enters the inverter feedback mode, feeding excess energy back to the power grid. When the power grid fails, the entire elevator emergency power intelligent switching and energy recovery system switches to emergency power supply mode within half a cycle. The capacitor energy storage module supplies power to the elevator system through a bidirectional DC / DC converter. The intelligent switching controller works in conjunction with the elevator main controller to control the traction machine to run at low speed to the nearest leveling position before opening the door to let people in.

Claims

1. An intelligent switching and energy recovery system for elevator emergency power supply, characterized in that, include: The power grid detection module is used to monitor the voltage amplitude, frequency and phase of the three-phase power grid in real time, determine the power supply status of the power grid, and output a power grid abnormality signal when a power grid abnormality is detected. The capacitor energy storage module is connected in parallel with the DC bus of the traction machine frequency converter to store the regenerative energy generated during the braking process of the traction machine, and to supply power to the elevator system as an emergency power source when the power grid is abnormal; A bidirectional DC / DC converter is connected between the DC bus of the traction machine frequency converter and the capacitor energy storage module to realize bidirectional energy flow between the DC bus of the traction machine frequency converter and the capacitor energy storage module. The inverter feedback module has its input end connected to the DC bus of the traction machine frequency converter and its output end connected to the power grid or the AC bus inside the building. It is used to feed back excess regenerative energy to the power grid with a unity power factor. The intelligent switching controller communicates with the power grid detection module, the capacitor energy storage module, the bidirectional DC / DC converter, the inverter feedback module, and the elevator main controller, respectively, and is used to switch the operating mode according to the status of the power grid detection module, the state of charge of the capacitor energy storage module, and the elevator operating status.

2. The elevator emergency power supply intelligent switching and energy recovery system according to claim 1, characterized in that, The intelligent switching controller includes: The status acquisition unit is used to acquire real-time power grid status signals, the state of charge and health status of the capacitor energy storage module, and elevator operation status signals. The mode decision unit has a built-in fuzzy reasoning algorithm model, which calculates the current operating mode to be entered based on the multi-dimensional information provided by the state acquisition unit. The switching execution unit sends control commands to the bidirectional DC / DC converter and inverter feedback module based on the decision results of the mode decision unit, and controls the seamless switching between the power grid and the emergency power supply.

3. The elevator emergency power supply intelligent switching and energy recovery system according to claim 2, characterized in that, The mode decision unit adopts an intelligent decision-making algorithm based on deep reinforcement learning. It uses the health status of the capacitor energy storage module, the current electricity price period, and the predicted value of the elevator load as the state space, the operation mode selection and charging and discharging power as the action space, and constructs a reward function based on comprehensive benefits. The optimal decision model is obtained through offline training.

4. The elevator emergency power supply intelligent switching and energy recovery system according to claim 1, characterized in that, It also includes the following operating modes: In the energy recovery charging mode, when the power grid is normal, the elevator traction machine is in the power generation state, and the state of charge of the capacitor energy storage module is lower than the preset charging upper limit threshold, the bidirectional DC / DC converter is controlled to store the regenerated electrical energy on the DC bus into the capacitor energy storage module. In the energy storage discharge auxiliary mode, when the power grid is normal, the elevator traction machine is in motor mode, and the state of charge of the capacitor energy storage module is higher than the preset discharge lower limit threshold, the bidirectional DC / DC converter is controlled to release the energy of the energy storage module to the traction machine frequency converter. In inverter feedback mode, when the grid is normal and the voltage of the capacitor energy storage module reaches the preset upper limit threshold, the inverter feedback module is activated to feed excess regenerated energy back to the grid. In emergency power supply mode, when the power grid detection module detects a power outage or abnormal voltage, it cuts off the power grid input and the capacitor energy storage module provides emergency power to the elevator system, controlling the traction machine to move the car to the nearest leveling position.

5. The elevator emergency power supply intelligent switching and energy recovery system according to claim 1, characterized in that, The power grid detection module is based on software phase-locked loop technology with rotating coordinate transformation and model reference adaptation, and can complete power outage detection within half a power grid cycle.

6. The elevator emergency power supply intelligent switching and energy recovery system according to claim 1, characterized in that, The capacitor energy storage module includes an energy storage array composed of multiple capacitor cells connected in series and a status monitoring unit for monitoring the voltage, current and temperature of the energy storage module; the status monitoring unit is also used to estimate the health status of the energy storage module in real time, and the intelligent switching controller dynamically adjusts the upper limit of the charge and discharge rate according to the health status value.

7. The elevator emergency power supply intelligent switching and energy recovery system according to claim 1, characterized in that, The bidirectional DC / DC converter adopts fully digital PWM control technology.

8. The elevator emergency power supply intelligent switching and energy recovery system according to claim 1, characterized in that, The inverter feedback module is based on the active inverter principle. It tracks grid synchronization through phase-locked loop technology and determines the phase angle and amplitude of the inverter output voltage through the phase amplitude control principle, so as to feed back electrical energy to the grid with unity power factor.

9. The elevator emergency power supply intelligent switching and energy recovery system according to claim 1, characterized in that, It includes an energy discharge protection module, which is connected in parallel with the capacitor energy storage module, and is used to discharge residual electrical energy in the elevator emergency power intelligent switching and energy recovery system in a controlled manner when the system is shut down for a long time or under maintenance.

10. The elevator emergency power supply intelligent switching and energy recovery system according to claim 1, characterized in that, It also includes a communication interface module for data interaction with the building energy management system or remote operation and maintenance platform, uploading the operation data, energy consumption statistics and fault alarm information of the entire elevator emergency power intelligent switching and energy recovery system.