Emergency power supply for elevator car

Abstract

The invention belongs to the technical field of emergency power supplies, and particularly relates to an elevator car emergency power supply which comprises an energy recovery module which comprises a three-phase rectifier bridge, a filter capacitor and a buck-boost DC / DC converter and is used for converting generated alternating current into direct current and stabilizing voltage; the energy storage module adopts a hybrid energy storage framework in which a lithium iron phosphate battery pack and a super capacitor bank are connected in parallel, and bidirectional energy flow is realized through a bidirectional DC / DC converter; the power management module comprises a BMS battery management system and an energy routing controller, and the energy routing controller is used for dynamically distributing the charge-discharge proportion of the super capacitor and the lithium battery pack; the emergency power supply switching module comprises a static change-over switch and a bidirectional inverter and is used for realizing seamless switching between the mains supply and the energy storage power supply; and the monitoring and communication module is used for real-time state feedback and remote control. According to the invention, through collaborative optimization of the three-phase rectifier bridge (with the efficiency of 98%) and the buck-boost DC / DC converter (with the efficiency of 92%), the total conversion efficiency reaches 85%, which is improved by 20-30% compared with a traditional scheme.

Description

Technical Field

[0001] The present invention relates to the technical field of emergency power supplies, and particularly to an emergency power supply for an elevator car. Background Art

[0002] With the continuous progress of society and the gradual advancement of urbanization, people's dependence on power supply has been increasing day by day. Even a short power supply interruption will cause relatively large economic losses to production and have an adverse social impact on people's lives. An emergency power supply is a device that can supply power to important loads of users for a short time when the normal power supply is interrupted. Its reliability and intelligence directly determine the emergency power supply situation when the normal power supply is interrupted, and it plays an important role in production and life.

[0003] The limitations of traditional elevator emergency power supplies are as follows:

[0004] Low energy utilization rate: Traditional emergency power supplies rely on the mains for charging and cannot recover the braking energy generated when the elevator descends (about 20 - 30% of the total elevator energy consumption), resulting in energy waste.

[0005] Slow switching response: When the mains power is interrupted, the response time of the mechanical switching switch is usually >100 ms, which may cause a short power outage of the elevator control system and pose a threat to the safety of passengers.

[0006] Single energy storage solution: Lead - acid batteries or a single lithium - ion battery pack cannot simultaneously meet the instantaneous high - power demand (such as the 2 - kW peak load when the motor starts) and the long - endurance requirement (such as more than 3 hours), and the system reliability is poor.

[0007] Therefore, corresponding improvements are made to solve this problem. Summary of the Invention

[0008] Based on the technical problems existing in the prior art, the present invention proposes an emergency power supply for an elevator car.

[0009] An emergency power supply for an elevator car proposed by the present invention includes an energy recovery module, an energy storage module, a power management module, an emergency power supply switching module, and a monitoring and communication module:

[0010] The energy recovery module includes a three - phase rectifier bridge, a filter capacitor, and a buck - boost DC / DC converter, and is used to convert the three - phase alternating current generated by the motor when the elevator descends into direct current and stabilize the voltage.

[0011] The energy storage module adopts a hybrid energy storage architecture with a lithium iron phosphate battery pack and a supercapacitor bank in parallel, and realizes bidirectional energy flow through a bidirectional DC / DC converter.

[0012] The power management module includes a BMS battery management system and an energy routing controller. The energy routing controller is used to dynamically allocate the charging and discharging ratios of the supercapacitor and the lithium battery pack.

[0013] The emergency power supply switching module includes a static transfer switch and a bidirectional inverter to achieve seamless switching between the commercial power and the energy storage power supply.

[0014] The monitoring and communication module is used for real-time status feedback and remote control.

[0015] When the car descends, the traction motor drives in reverse, outputting three-phase alternating current (with a power of about 2 - 5 kW, varying according to the load and speed). The rectifier converts the alternating current into direct current (600 VDC), which is stepped down to 48 V by a buck-boost DC / DC converter and then input into the energy storage module, thus achieving efficient energy recovery and significantly reducing energy consumption.

[0016] Preferably, the three-phase rectifier bridge of the energy recovery module uses an IGBT module (such as FF300R12KE3), the buck-boost DC / DC converter uses an H-bridge + inductor topology, and the control chip is UC3845.

[0017] Preferably, the bidirectional inverter uses a full-bridge IGBT structure, and the control chip is DSP TMS320F28335, which converts direct current into alternating current (such as 220 VAC) to supply the elevator control system. The response time of the static transfer switch is < 10 ms to avoid elevator out-of-control.

[0018] Preferably, the supercapacitor bank in the hybrid energy storage architecture responds to short-term high-power loads preferentially, and the lithium iron phosphate battery pack is responsible for continuous energy supply.

[0019] Preferably, the circuit system of the emergency power supply has overvoltage / overcurrent protection, temperature protection, and electromagnetic compatibility design.

[0020] Preferably, the BMS battery management system is used to monitor the SOC (remaining capacity), SOH (health state), and temperature of the lithium iron phosphate battery pack to achieve balanced charging.

[0021] Preferably, the monitoring and communication module includes a microcontroller (such as STM32) and a 4G / WiFi communication module. The microcontroller is used to collect voltage, current, and temperature data, and the 4G / WiFi communication module is used to upload data to the cloud platform to support remote fault diagnosis.

[0022] Preferably, the battery compartment of the emergency power supply uses a ceramic fiber heat insulation layer, which can improve the fire resistance of the emergency power supply.

[0023] Preferably, a cooling fan and a temperature detection module are also installed in the battery compartment of the emergency power supply. The cooling fan is automatically started when the temperature exceeds 60°C. When the temperature detection module detects that the internal temperature of the battery compartment reaches the set 60°C, it will send a signal to the microcontroller. After processing the signal, the microcontroller will start the cooling fan to cool down the emergency power supply. When the temperature > 70°C, the charging and discharging are cut off, thereby further improving the fire prevention performance of the emergency power supply.

[0024] Compared with the prior art, the present invention provides an elevator car emergency power supply, which has the following beneficial effects:

[0025] 1. An elevator car emergency power supply, through the collaborative optimization of a three-phase rectifier bridge (efficiency 98%) and a buck-boost DC / DC converter (efficiency 92%), the total conversion efficiency reaches 85%, which is 20 - 30% higher than the traditional scheme. For example, for an elevator in a 20-story office building with 20 daily down trips, about 5000 kWh of energy can be recovered annually after transformation, reducing carbon emissions by 3.5 tons, thereby realizing efficient energy recovery and significantly reducing energy consumption.

[0026] 2. An elevator car emergency power supply, the response time of the static transfer switch (STS) < 10 ms (measured 8.5 ms), avoiding power loss of the elevator control system. Load priority: intelligently cut off non-essential loads (such as advertising screens), and give priority to ensuring emergency calls (< 500 W) and ventilation (< 200 W) to ensure the safety of passengers, thereby achieving a fast emergency response and ensuring safe operation.

[0027] 3. An elevator car emergency power supply, the supercapacitor bank (500 F / 48 V) can provide a peak power of 2 kW within 30 seconds to meet the motor startup requirements and has instantaneous power support. The lithium iron phosphate battery pack (48 V / 100 Ah) provides 3 kWh of energy and has a battery life of 3 hours at a full load of 1 kW, which is 50% longer than the traditional lead-acid battery scheme, having a long battery life.

[0028] 4. An elevator car emergency power supply, with a dynamic distribution strategy: when the elevator starts, the supercapacitor releases 70% of the power, and the lithium battery pack compensates 30%, reducing the large-current discharge loss of the battery and extending the life to 2000 cycles (about 500 cycles in the traditional scheme); with an equalization charging technology: the BMS system realizes the equalization of the single-cell voltage (accuracy ±5 mV), avoiding the capacity attenuation of the battery pack and reducing the maintenance cost by 60%, thereby achieving intelligent energy management and extending the equipment life.

[0029] 5. An emergency power supply for an elevator car, with overvoltage and overcurrent protection: The fast fuse (500A / 600V) has a response time < 10 μs, and the voltage comparator triggers the IGBT soft turn-off to protect the circuit from overload damage; it has temperature management: the ceramic fiber heat insulation layer in the battery compartment is combined with the NTC thermistor, automatically dissipates heat when the temperature exceeds 60°C, cuts off charging and discharging when the temperature exceeds 70°C, and ensures the safe operation of the system, thus achieving multiple safety protections and adapting to complex environments. Brief Description of the Drawings

[0030] Figure 1 FIG. is a system architecture diagram of an emergency power supply for an elevator car proposed by the present invention;

[0031] Figure 2 FIG. is a circuit diagram of an energy recovery module of an emergency power supply for an elevator car proposed by the present invention;

[0032] Figure 3 FIG. is a circuit diagram of an energy storage module and an emergency power supply switching module of an emergency power supply for an elevator car proposed by the present invention. Detailed Embodiments

[0033] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0035] Refer to Figures 1-3 , an emergency power supply for an elevator car, including an energy recovery module, an energy storage module, a power management module, an emergency power supply switching module, and a monitoring and communication module;

[0036] (1) Energy recovery module

[0037] Function: Convert the gravitational potential energy during the downward movement of the elevator into electrical energy and stabilize the voltage.

[0038] Components:

[0039] Three-phase rectifier bridge: IGBT module (model FF300R12KE3), supporting PWM rectification, with a conversion efficiency of 98%;

[0040] Filter capacitor: 1000 μF / 450V, with a ripple suppression rate > 95%;

[0041] Buck-boost DC / DC converter: H-bridge + inductor topology, control chip UC3845, conversion efficiency 92%;

[0042] Parameters: input voltage range 380VAC ± 10%, output 48VDC ± 1%.

[0043] (2) Energy storage module

[0044] Hybrid architecture:

[0045] Lithium iron phosphate battery pack: 13 series LiFePO4 (48V / 100Ah), energy density 160Wh / kg, cycle life > 2000 times;

[0046] Supercapacitor bank: 16 series Maxwell 3000F (48V), power density 3000W / kg, response time < 1ms;

[0047] Bidirectional DC / DC: chip LTC3780, supports ±5kW power flow, efficiency 95%.

[0048] (3) Power management module

[0049] BMS battery management system: TIBQ76952 chip, supports:

[0050] SOC estimation accuracy ±3%, individual cell voltage equalization current 500mA, and temperature compensation range -20°C to 60°C, achieving balanced charging;

[0051] Energy routing controller strategy:

[0052] When the elevator starts: the supercapacitor releases 70% of the power, and the lithium battery pack compensates 30%;

[0053] Charging priority: supercapacitor → lithium battery pack (charging currents are 50A and 20A respectively).

[0054] (4) Emergency power supply switching module

[0055] Static transfer switch: SSTS32400, switching time < 10ms, supports 400A surge current;

[0056] Bidirectional inverter: full-bridge IGBT structure, control chip TMS320F28335, output 220VAC ± 5%, THD < 3%.

[0057] (5) Monitoring and communication module

[0058] Microcontroller: STM32F407, sampling rate 10kHz, used to collect voltage, current, and temperature data;

[0059] Communication protocol: Modbus RTU + 4G / WiFi, supporting OTA upgrade.

[0060] The relevant work process is as follows:

[0061] 1. Energy recovery process

[0062] Step 1: When the elevator descends, it triggers the motor power generation mode and outputs three-phase 380VAC power (frequency 50Hz ± 5%);

[0063] Step 2: The three-phase rectifier bridge converts the alternating current into 600VDC, and the filter capacitor filters out high-frequency ripples;

[0064] Step 3: The buck-boost DC / DC converter steps down the voltage to 48VDC and outputs it to the energy storage module;

[0065] Energy distribution:

[0066] Charging current of the supercapacitor bank: 50A (charging time < 30 seconds);

[0067] Charging current of the lithium battery pack: 20A (charging time 2 hours).

[0068] 2. Emergency power supply process

[0069] Step 1: Detect the interruption of the mains power supply (voltage threshold 180VAC), and trigger the static transfer switch to switch;

[0070] Step 2: Start the bidirectional inverter to invert 48VDC into 220VAC;

[0071] Load management:

[0072] Priority 1: Emergency call (< 500W), ventilation system (< 200W);

[0073] Priority 2: Lighting system (< 300W); Non-essential loads are automatically cut off (such as advertising screens).

[0074] 3. Safety protection mechanism

[0075] Overvoltage protection: When the bus voltage > 650V, trigger the IGBT soft turn-off;

[0076] Overcurrent protection: Fast fuse (500A / 600V), response time < 10μs;

[0077] Temperature protection: When the temperature in the battery compartment > 60°C, start the cooling fan, and cut off the charge and discharge when > 70°C.

[0078] When designing an elevator emergency power supply system, multiple key aspects rely on engineering calculation formulas to ensure performance, safety, and compliance. The following are the core calculation modules involved in the solution and their corresponding formulas:

[0079] When the elevator is descending, the theoretical maximum value of the potential energy of the car converted into electrical energy is:

[0080] E potential = m·g·h·η mech

[0081] Where, m: car load (kg), for example, the standard load is 1000 kg; g: acceleration due to gravity (9.8 m / s 2 ); h: descending height (m), for example, about 30 m for a 10-story building; η mech : mechanical transmission efficiency (usually 50 - 70%).

[0082] Calculation of electrical energy conversion efficiency, the total recovery efficiency needs to consider electrical conversion losses:

[0083] η total = η rectifier ·η DC / DC ·η battery

[0084] Where, η rectifier : rectification efficiency (90 - 95%); η DC / DC : DC / DC conversion efficiency (92 - 98%); η battery : battery charging efficiency (95 - 98%).

[0085] Calculation of the lithium battery pack capacity, design the capacity according to the emergency load power and the target endurance time:

[0086]

[0087] Where, P load : emergency load power (W), for example, lighting + ventilation + communication = 800 W; t: target endurance time (h), for example, 3 hours; η inverter : inverter efficiency (85 - 95%); DOD: battery discharge depth (up to 80% for lithium iron phosphate).

[0088] Instantaneous power support of supercapacitors, supercapacitors need to meet short-term high-power requirements (such as motor startup):

[0089]

[0090] Where, C: total capacitance value of the capacitor (F), for example, 500 F; V max / V min : working voltage range (such as 48V → 36V); t: discharge time (s).

[0091] It should be understood that in various embodiments of the present application, the magnitudes of the serial numbers of the above processes do not imply the order of execution, and the order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0092] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professionals can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present application.

[0093] In several embodiments provided by the present application, it should be understood that the disclosed overall system, device, and method can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another overall system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0094] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place, or can be distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0095] In addition, the functional units in each embodiment of the present application can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit.

[0096] As described above, the above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should all be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An elevator car emergency power supply, comprising an energy recovery module, an energy storage module, a power management module, an emergency power supply switching module, and a monitoring and communication module, characterized in that: The energy recovery module includes a three-phase rectifier bridge, a filter capacitor, and a buck-boost DC / DC converter, and is used to convert the three-phase alternating current generated by the motor during elevator descent into direct current and stabilize the voltage; The energy storage module adopts a hybrid energy storage architecture with a lithium iron phosphate battery pack and a supercapacitor bank connected in parallel, and realizes bidirectional energy flow through a bidirectional DC / DC converter; The power management module includes a BMS battery management system and an energy routing controller, and the energy routing controller is used to dynamically allocate the charge and discharge ratios of the supercapacitor and the lithium battery pack; The emergency power supply switching module includes a static transfer switch and a bidirectional inverter, and realizes seamless switching between the commercial power and the energy storage power supply; The monitoring and communication module is used for real-time status feedback and remote control.

2. The emergency power supply for an elevator car according to claim 1, characterized in that, The three-phase rectifier bridge of the energy recovery module adopts an IGBT module, and the buck-boost DC / DC converter adopts an H-bridge + inductor topology.

3. An emergency power supply for an elevator car according to claim 1, characterized in that, The bidirectional inverter adopts a full-bridge IGBT structure to invert direct current into alternating current to supply the elevator control system. The response time of the static transfer switch is <10 ms to prevent the elevator from getting out of control.

4. An emergency power supply for an elevator car according to claim 1, characterized in that, In the hybrid energy storage architecture, the supercapacitor bank responds preferentially to short-term high-power loads, and the lithium iron phosphate battery pack is responsible for continuous energy supply.

5. An emergency power supply for an elevator car according to claim 1, wherein, The circuit system of the emergency power supply has overvoltage / overcurrent protection, temperature protection, and electromagnetic compatibility design.

6. The emergency power supply for an elevator car according to claim 1, characterized in that, The BMS battery management system is used to monitor the SOC (remaining capacity), SOH (health status), and temperature of the lithium iron phosphate battery pack, and realizes balanced charging.

7. An emergency power supply for an elevator car according to claim 1, characterized in that, The monitoring and communication module includes a microcontroller and a 4G / WiFi communication module. The microcontroller is used to collect voltage, current, and temperature data, and the 4G / WiFi communication module is used to upload data to the cloud platform to support remote fault diagnosis.

8. An emergency power supply for an elevator car according to claim 1, characterized in that, The battery compartment of the emergency power supply adopts a ceramic fiber heat insulation layer.

9. The emergency power supply for an elevator car according to claim 7, characterized in that, A cooling fan and a temperature detection module are also installed in the battery compartment of the emergency power supply. The cooling fan is automatically started when the temperature exceeds 60 °C.

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