Alternating current and direct current power supply switching circuit for elevator

Abstract

The utility model discloses an AC / DC power supply switching circuit for an elevator, which belongs to the technical field of elevator power control, and comprises an MCU microcontroller module, a CAN data communication module, an ADC sampling module and an IGBT driving module, the MCU microcontroller module is respectively connected with the CAN data communication module and the ADC sampling module, and the output end of the MCU module is connected with the IGBT driving module; according to the utility model, after ADC initialization and CAN communication initialization are carried out, a self-checking program is executed, and ADC acquisition and CAN communication are ensured to be normal. On the basis of ADC acquisition and data analysis, real-time monitoring of three-phase alternating current and real-time switching control of a main and standby power supply redundant system are realized. And normal operation of the elevator is ensured. The utility model has the characteristics of reliable structure, stable performance, high fault-tolerant mechanism, fast switching speed, intelligent control, wide application range and the like.

Description

Technical Field

[0001] This utility model relates to the field of elevator power control technology, specifically to an AC / DC power switching circuit for elevators. Background Technology

[0002] An elevator is a power-driven electromechanical device that uses a car driven along rigid guide rails or steps running along a fixed route to lift or transport people or goods horizontally. It includes passenger (freight) elevators, escalators, and moving walkways. This utility model also includes elevators installed in non-public places and intended for single-family use. With the acceleration of urbanization and the increase in building height, the safety and reliability of elevators, as core equipment in vertical transportation, have become a major concern. As special equipment, the safety and reliability of the power supply system of elevators directly affect passenger safety and stable equipment operation. Especially in the replacement of old elevators and the development of new elevator technologies, AC / DC power switching technology has become one of the key technologies for solving power supply stability, energy saving, and emergency response issues. The core objective of AC / DC power switching technology is to quickly switch to DC emergency power when the power grid is interrupted, ensuring the elevator stops safely and passengers are released. Compared to mechanical rescue operations, automatic rescue operation devices equipped with AC / DC power switching circuits are more timely, efficient, and convenient. Especially for elevators installed in non-public places and used by a single family for personalized needs, the device equipped with AC / DC power switching technology is even more essential.

[0003] The current "Rules for Supervision and Periodic Inspection of Elevators" (TSG T7001-2023) stipulates that the power supply for firefighter elevators and lighting systems must consist of a primary power supply and a secondary power supply (emergency power supply, backup power supply, or a second power supply) located within the fire protection zone. For traction-driven passenger elevators and traction-driven freight elevators (excluding firefighter elevators), if equipped with an automatic rescue device, this device can automatically engage in rescue operation when the mains power is interrupted. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an AC / DC power switching circuit for elevators.

[0005] The objective of this utility model is achieved through the following technical solution:

[0006] This utility model discloses an AC / DC power switching circuit for an elevator, comprising: an MCU microcontroller module, a CAN data communication module, an ADC sampling module, and an IGBT driver module. The MCU microcontroller module is connected to the CAN data communication module and the ADC sampling module, respectively, and the output terminal of the MCU microcontroller module is connected to the IGBT driver module.

[0007] The ADC sampling module includes a voltage transformer, a signal conditioning module, an ADC module, a first isolation power supply module, an LDO buck module, and a first digital isolation chip. The output of the voltage transformer is connected to the input of the signal conditioning module, the output of the signal conditioning module is connected to the input of the ADC module, the output of the first isolation power supply module is connected to the input of the LDO buck module and the input of the first digital isolation chip, respectively; the output of the LDO buck module is connected to the input of the ADC module, the ADC module is connected to the first digital isolation chip, and the first digital isolation chip is connected to an MCU microcontroller module.

[0008] The IGBT driver module includes a second isolated power supply module, a second digital isolation chip, and an LGBT driver module. The output terminal of the second isolated power supply module is connected to the input terminal of the second digital isolation chip and the input terminal of the LGBT driver module, respectively. The second digital isolation chip is connected to the LGBT driver module and is also connected to the MCU microcontroller module.

[0009] The CAN data communication module includes a third isolation power supply module, a third digital isolation chip, a CAN chip, and an interface protection circuit. The output terminal of the third isolation power supply module is connected to the input terminals of the third digital isolation chip and the CAN chip, respectively. The third digital isolation chip is connected to the CAN chip, the CAN chip is connected to the interface protection circuit, and the third digital isolation chip is also connected to the MCU microcontroller module.

[0010] Furthermore, the MCU microcontroller module also includes peripheral circuits, which include a reset circuit, a conditioning circuit, a crystal oscillator, an alarm circuit, and a status indicator. The input terminals of the MCU microcontroller module are respectively connected to the output terminals of the reset circuit, the conditioning circuit, and the crystal oscillator. The output terminals of the MCU microcontroller module are respectively connected to the input terminals of the alarm circuit and the status indicator. The input terminals of the reset circuit, the conditioning circuit, and the crystal oscillator are respectively connected to the local power supply.

[0011] Furthermore, it also includes a power management module, which is connected to the MCU microcontroller module.

[0012] Furthermore, the MCU microcontroller module is equipped with an SPI interface and a CAN interface. The MCU microcontroller module is connected to the first digital isolation chip through the SPI interface and to the second digital isolation chip through the CAN interface.

[0013] Furthermore, it also includes an IGBT module and a CAN data communication host. The input terminal of the IGBT module is connected to the IGBT driver module, and the CAN data communication host is also connected to the CAN data communication module.

[0014] The beneficial effects of this utility model are:

[0015] 1) This utility model can accurately detect the power failure of the first power supply by judging the main power supply failure logic, power recovery detection judgment, main power supply quality monitoring, and communication diagnosis, and then issue a backup power supply switching control command. When the main power supply is detected to be restored and the power supply quality of the main power supply is judged, the control command to switch to the main power supply is then issued, realizing the automatic switching function of AC and DC power supply, avoiding false switching caused by voltage instability, etc. Its detection cycle can be designed in a targeted manner through program adjustment and optimization. Attached Figure Description

[0016] Figure 1 This is an example diagram of an elevator power supply that uses an AC / DC switching circuit;

[0017] Figure 2 This is an architectural block diagram of the MCU microcontroller module according to an embodiment of the present invention;

[0018] Figure 3 This is a flowchart illustrating the usage of this utility model;

[0019] Figure 4 This is a schematic diagram of the specific structure of an embodiment of the present utility model;

[0020] Figure 5 This is a schematic diagram of the structure of the MCU microcontroller module according to an embodiment of the present invention;

[0021] Figure 6 This is a circuit diagram of the MCU microcontroller module according to an embodiment of the present invention;

[0022] Figure 7 This is a schematic diagram of the ADC sampling module according to an embodiment of the present invention;

[0023] Figure 8 This is a circuit diagram of the ADC sampling module according to an embodiment of the present invention;

[0024] Figure 9 This is a schematic diagram of the IGBT driver module according to an embodiment of the present invention;

[0025] Figure 10 This is a circuit diagram of the IGBT driver module according to an embodiment of the present invention;

[0026] Figure 11 This is a schematic diagram of the CAN data communication module according to an embodiment of the present invention;

[0027] Figure 12 This is a circuit diagram of the CAN data communication module according to an embodiment of the present invention;

[0028] Figure 13 This is a circuit diagram of the power management module according to an embodiment of the present invention. Detailed Implementation

[0029] The technical solution of this utility model will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] This utility model discloses an AC / DC power switching circuit for elevators, the specific structural diagram of which is shown below. Figure 4 As shown, the system includes an MCU microcontroller module, a CAN data communication module, an ADC sampling module, and an IGBT driver module. The MCU microcontroller module is connected to both the CAN data communication module and the ADC sampling module, and its output is connected to the IGBT driver module. It features reliable structure, stable performance, high fault tolerance, fast switching speed, intelligent control, and wide applicability. The data interfaces between each module and the main controller (MCU microcontroller module) employ isolation technology, completely separating high-voltage and low-voltage circuits to ensure the safe operation of each module. The MCU microcontroller module, as the system control core, communicates with the ADC sampling module via an SPI interface to obtain the quantized transformer voltage signal and uses an internal algorithm to monitor the external high-voltage (AC380V power / mains) power quality in real time. When the external power supply is abnormally interrupted, a drive switching signal is quickly output to the IGBT driver module, which then performs a rapid switch between the main power supply and the backup power supply (switching time better than 1ms). The CAN data interface can controllably upload signals such as the current power supply voltage value, power quality, and local power level, facilitating external controllers to determine the current node's operating status. The MCU microcontroller module integrates a main / backup power detection unit, a main / backup power switching control unit, a communication diagnostic unit, and a main power quality monitoring unit. Through main power failure logic judgment, power recovery detection judgment, main power quality monitoring, and communication diagnostics, it can accurately detect the power failure of the primary power source and issue a backup power switching control command. When the main power source is detected to be restored and its power supply quality is assessed, it switches back to the main power source, achieving automatic AC / DC power switching and avoiding erroneous switching caused by voltage instability. Its detection cycle can be customized through program adjustments and optimizations. It can quickly switch to a secondary power source (including grid power, AC power, generator power, and backup battery power) when the AC main power source fails, ensuring the safe operation of the elevator.

[0031] For example, an example diagram of an elevator power supply using an AC / DC switching circuit is shown below. Figure 1 As shown, under normal power supply conditions, the first power source, namely the mains power (380V AC), is used. When the first power source fails and power is interrupted, elevators equipped with a second power source need to switch from the first to the second power source to ensure normal operation. This switching is achieved using a switch consisting of an automatic switching circuit.

[0032] For example, the architecture block diagram of the MCU microcontroller module is as follows: Figure 2 As shown, this module integrates existing main / backup power detection units, main / backup power switching control units, communication diagnostic units, and main power quality monitoring units. During operation, this invention first performs peripheral initialization, including ADC initialization and CAN communication initialization. After initialization, a self-test program is executed to ensure normal ADC acquisition and CAN communication. Based on ADC acquisition and data analysis, it realizes real-time monitoring of three-phase AC power and real-time switching control of the main / backup power redundancy system to ensure the normal operation of the elevator.

[0033] For example, the flowchart of the use of this utility model is as follows: Figure 3 As shown, the three-phase AC power is converted into a voltage level that can be processed by the ADC sampling module through a voltage transformer. The MCU microcontroller module controls the ADC to acquire voltage signals at high speed. This invention is designed with a power outage detection confirmation time of 20ms, which is the single-cycle time of a single-phase AC power. When the MCU microcontroller module detects that the voltage value is 0V for 20ms, it considers the external AC power to be interrupted. At this time, the MCU microcontroller module will control the IGBT drive module to switch the power supply system to the UPS. For power restoration detection, the main power (three-phase AC power) input stabilization time is designed to be 3s. By performing FFT transformation on the continuously sampled data of the ADC, it is calculated whether the signal frequency is stable at 50Hz within this time. When the condition is met, it is considered that the main power has been restored, and the MCU microcontroller module controls the IGBT drive module to switch to the main power. For main power quality monitoring, by performing FFT transformation on the continuously sampled data of the ADC, it is calculated whether there is a stable 50Hz harmonic in the signal frequency. For communication diagnosis, CAN communication output is used, and the data includes power control status and power quality status.

[0034] Specifically, the ADC sampling module includes a voltage transformer, a signal conditioning module, an ADC module, a first isolation power supply module, an LDO buck module, and a first digital isolation chip. A schematic diagram of the ADC sampling module is shown below. Figure 7 As shown, the circuit diagram of the ADC sampling module is as follows: Figure 8As shown; the output of the voltage transformer is connected to the input of the signal conditioning module, the output of the signal conditioning module is connected to the input of the ADC module, the output of the first isolated power supply module is connected to the input of the LDO step-down module and the input of the first digital isolation chip respectively; the output of the LDO step-down module is connected to the input of the ADC module, the ADC module is connected to the first digital isolation chip, and the first digital isolation chip is connected to the MCU microcontroller module; the ADC sampling module adopts a power isolation design, with a voltage isolation level of 1000VDC, meeting the system's electrical isolation level requirements. The isolated power supply module converts the system input 5V power supply to an isolated 5V power supply output, which is then regulated by the LDO to output a low-noise 3.3V power supply to power the ADC analog chip. The AC power is transformed from high-voltage AC to low-voltage AC by the voltage transformer, and after voltage division and filtering by the signal conditioning circuit, it is output to the ADC chip. The MCU outputs an SPI drive signal through the SPI interface to the ADC module via the digital isolation chip, reads the ADC quantization data, processes the data using the existing internal algorithm, and outputs the judgment result.

[0035] Specifically, the structural diagram of the IGBT driver module is as follows: Figure 9 As shown; the circuit diagram of the IGBT driver module is as follows. Figure 10 As shown, the IGBT driver module includes a second isolated power supply module, a second digital isolation chip, and an LGBT driver module. The output of the second isolated power supply module is connected to the input of the second digital isolation chip and the input of the LGBT driver module, respectively. The second digital isolation chip is connected to the LGBT driver module and also to an MCU microcontroller module. The control signal from the MCU is output to the IGBT driver circuit after passing through the digital isolation chip to control the switching state of the IGBT, thereby completing the switching state switching of the power IGBT. Since the power IGBT involves high-voltage circuits, an isolation design is required. This ensures strict separation of high and low voltage circuits, so that a breakdown or burnout fault in the high-voltage circuit will not affect the detection function of the low-voltage circuit. The IGBT driver module uses the EXB841 module manufactured by Fuji Electric Corporation of Japan. This module integrates voltage isolation drive and overcurrent monitoring functions, facilitating integration and use.

[0036] Specifically, the structural diagram of the CAN data communication module is as follows: Figure 11 As shown; the circuit diagram of the CAN data communication module is as follows. Figure 12As shown, the CAN data communication module includes a third isolated power supply module, a third digital isolation chip, a CAN chip, and an interface protection circuit. The output of the third isolated power supply module is connected to the input of the third digital isolation chip and the CAN chip, respectively. The third digital isolation chip is connected to the CAN chip, and the CAN chip is connected to the interface protection circuit. The third digital isolation chip is also connected to the MCU microcontroller module. It can provide one reliable CAN communication channel. Since the external device of this invention is high voltage, the CAN data communication module also adopts an isolated electrical isolation design. The CAN data communication module supports up to 128 data nodes in a network, with a communication distance exceeding 1km, meeting the application requirements for network networking. The data communication content includes local voltage detection, power supply voltage, and power quality detection data, etc.

[0037] Specifically, the structural diagram of the MCU microcontroller module is as follows: Figure 5 As shown, the circuit diagram of the MCU microcontroller module is as follows: Figure 6 As shown, the MCU microcontroller module also includes peripheral circuitry, including a reset circuit, a conditioning circuit, a crystal oscillator, an alarm circuit, and a status indicator. The input terminals of the MCU microcontroller module are connected to the output terminals of the reset circuit, conditioning circuit, and crystal oscillator, respectively. The output terminals of the MCU microcontroller module are connected to the input terminals of the alarm circuit and the status indicator, respectively. The input terminals of the reset circuit, conditioning circuit, and crystal oscillator are connected to the local power supply. The conditioning circuit filters the local input voltage and then samples it using the MCU's internal ADC to achieve local voltage monitoring. The reset circuit provides an external reset signal after system power-on to ensure normal MCU operation. The external crystal oscillator circuit provides a set of highly reliable and high-quality clock signals as the MCU's input clock, ensuring stable operation of the MCU core. The alarm circuit and status indicator work together to indicate the current MCU operating status and provide audible and visual alarms in case of power failure, facilitating fault identification by maintenance personnel.

[0038] Specifically, it also includes a power management module, the circuit diagram of which is shown below. Figure 13 As shown, the power management module is connected to the MCU microcontroller module.

[0039] Specifically, the MCU microcontroller module is equipped with an SPI interface and a CAN interface. The MCU microcontroller module is connected to the first digital isolation chip through the SPI interface and to the second digital isolation chip through the CAN interface.

[0040] Specifically, it also includes an IGBT module and a CAN data communication host. The input terminal of the IGBT module is connected to the IGBT driver module, and the CAN data communication host is also connected to the CAN data communication module.

[0041] Exemplarily, this utility model designs a stable and reliable circuit, equipped with an MCU microcontroller to achieve automatic switching between AC and DC power supplies. It features reliable structure, stable performance, high fault tolerance, fast switching speed, intelligent control, and wide applicability. In particular, through main power failure logic judgment, power recovery detection judgment, main power quality monitoring, and a communication diagnostic system, it can quickly determine the actual state of main power supply failure and restoration, achieving rapid AC / DC power switching and avoiding malfunctions caused by voltage instability. Furthermore, it can adjust the program according to different switching time requirements and relevant standards and specifications, exhibiting high scalability. The circuit designs of the CAN data communication module, ADC sampling module, IGBT driver module, and power management module are characterized by stable structure and reliable performance. The data interfaces between each module and the main controller (MCU microcontroller) employ isolation technology, completely separating high-voltage and low-voltage circuits to ensure the safe operation of each module.

[0042] For example, this utility model can be extended to fields requiring highly reliable power supplies, such as intelligent buildings and medical equipment. Combined with AI intelligent monitoring functions, it achieves comprehensive intelligence in elevator power systems. Power switching technology is not only a guarantee for emergency power supply in elevators, but also a core driving force for promoting the green and intelligent transformation of the industry. From the renovation of old elevators to new DC drive systems, its application scenarios are constantly expanding. In the future, with the deep integration of high-voltage DC technology and AI, elevators will move towards a new stage of higher energy efficiency and lower maintenance costs, providing solid support for the sustainable development of urban vertical transportation. This utility model is used in the practice of renovating old elevators and new elevators. Driven by the demand for renovating old elevators, many places across the country have carried out special renovations for elevators over 15 years old, and a large number of elevators have been replaced through the support of national debt funds. AC / DC switching technology, due to its low cost and rapid deployment, has become the preferred solution for retrofitting elevators. Firefighter elevators should be equipped with a secondary power supply, and the switching of the secondary power supply should automatically occur when the primary power supply fails. With technological advancements and increasing emphasis on elevator safety, emergency rescue devices equipped with automatic switching circuits can quickly, promptly, and automatically engage in emergency rescue after a main power supply failure, rescuing trapped passengers. This not only enhances elevator safety but also significantly reduces the manpower costs of emergency rescue after a main power supply failure. Furthermore, the increasing number of home elevators makes the configuration of automatic rescue devices with automatic switching circuits essential. Energy-saving innovations in new elevators, through the combination of DC inverters and energy storage devices, significantly reduce operating energy consumption. In addition, the widespread adoption of PLC control technology (such as automatic floor scheduling and emergency alarm functions) and its synergy with AC / DC switching systems further enhance elevator automation. The industry penetration of high-voltage DC power supply, particularly in data centers, is gradually migrating to the elevator industry. Challenges and future trends include: technical challenges such as arc suppression, and the need to optimize IGBT heat dissipation design and current distribution strategies during high-voltage DC switching. Compatibility is a concern, as the system needs to be adapted to different brands of elevators, and standardized interfaces are not yet widely available.

[0043] For example, this utility model can be combined with AI technology to achieve dynamic load scheduling and fault prediction. For instance, by analyzing elevator operating data using AI, switching timing and energy distribution can be optimized. The application of flexible DC power supply technology above 800V can support the needs of higher-power elevators while being compatible with new energy sources such as photovoltaics. Linear motor drives, due to their contactless and high-precision characteristics, can be deeply integrated with DC power supply systems, reducing energy loss in traditional traction mechanisms and improving operating efficiency.

[0044] The above description is merely a preferred embodiment of this utility model. It should be understood that this utility model is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this utility model should be protected within the scope of the appended claims.

Claims

1. An AC-DC power switching circuit for an elevator, characterized by The application relates to an IGBT (Insulated Gate Bipolar Transistor) module and a CAN (Controller Area Network) data communication module. The IGBT module comprises an MCU (Micro Controller Unit) microcontroller module, a CAN data communication module, an ADC (Analog-to-Digital Converter) sampling module and an IGBT drive module, wherein the MCU microcontroller module is connected with the CAN data communication module and the ADC sampling module respectively, and an output end of the MCU microcontroller module is connected with the IGBT drive module. The ADC sampling module comprises a voltage transformer, a signal conditioning module, an ADC module, a first isolation power supply module, an LDO (Low Dropout) voltage reduction module and a first digital isolation chip, wherein an output end of the voltage transformer is connected with an input end of the signal conditioning module, an output end of the signal conditioning module is connected with an input end of the ADC module, an output end of the first isolation power supply module is connected with an input end of the LDO voltage reduction module and an input end of the first digital isolation chip respectively, an output end of the LDO voltage reduction module is connected with an input end of the ADC module, the ADC module is connected with the first digital isolation chip, and the first digital isolation chip is connected with the MCU microcontroller module. The IGBT drive module comprises a second isolation power supply module, a second digital isolation chip and an IGBT drive module, wherein an output end of the second isolation power supply module is connected with an input end of the second digital isolation chip and an input end of the IGBT drive module respectively, the second digital isolation chip is connected with the IGBT drive module, and the second digital isolation chip is further connected with the MCU microcontroller module. The CAN data communication module comprises a third isolation power supply module, a third digital isolation chip, a CAN chip and an interface protection circuit, wherein an output end of the third isolation power supply module is connected with input ends of the third digital isolation chip and the CAN chip respectively, the third digital isolation chip is connected with the CAN chip, the CAN chip is connected with the interface protection circuit, and the third digital isolation chip is further connected with the MCU microcontroller module.

2. The AC-DC power switching circuit for an elevator according to claim 1, characterized by: The MCU microcontroller module further comprises a peripheral circuit, wherein the peripheral circuit comprises a reset circuit, a conditioning circuit, a crystal oscillator, an alarm circuit and a state indicator, input ends of the MCU microcontroller module are connected with output ends of the reset circuit, the conditioning circuit and the crystal oscillator respectively, output ends of the MCU microcontroller module are connected with an input end of the alarm circuit and an input end of the state indicator respectively, and input ends of the reset circuit, the conditioning circuit and the crystal oscillator are connected with a local power supply.

3. The AC-DC power switching circuit for an elevator according to claim 1, characterized by: The application further comprises a power management module, wherein the power management module is connected with the MCU microcontroller module.

4. The AC / DC power switching circuit for an elevator according to claim 1, characterized by: The MCU microcontroller module is provided with an SPI (Serial Peripheral Interface) interface and a CAN interface, the MCU microcontroller module is connected with the first digital isolation chip through the SPI interface, and the MCU microcontroller module is connected with the second digital isolation chip through the CAN interface.

5. The AC / DC power switching circuit for an elevator according to claim 1, characterized by: The application further comprises an IGBT module and a CAN data communication host, wherein an input end of the IGBT module is connected with the IGBT drive module, and the CAN data communication host is further connected with the CAN data communication module.

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