Elevator frequency converter safety control method, elevator frequency converter, control system and elevator

Abstract

The invention relates to an elevator frequency converter safety control method, an elevator frequency converter, a control system and an elevator, and the method comprises the steps that whether a switching power supply circuit is powered off or not is detected; when power failure is judged, the brake unit is controlled to be communicated with the brake resistor and the direct-current bus so as to discharge the direct-current bus; by reconstructing a power supply framework and a power-off control mode of the frequency converter, power supply of the frequency converter is changed into an independent power supply in an elevator control system from a direct-current bus influenced by commercial power, and an energy storage circuit is introduced to provide electric energy for the system after power off, so that the frequency converter can still keep working, and an electronic star sealing function is effectively realized; meanwhile, on the basis, through the safety control method, when power failure is detected, the brake resistor is driven to be connected into the direct-current bus of the frequency converter, rapid discharging of the direct-current bus is achieved, and therefore the potential safety hazard of electric shock of maintenance personnel caused by slow voltage reduction of the direct-current bus after power failure due to the influence of bus capacitance is avoided.

Description

Technical Field

[0001] This application relates to the field of elevator technology, and in particular to elevator inverter safety control methods, elevator inverters, control systems, and elevators. Background Technology

[0002] With the continuous advancement of elevator control system technology, components such as the star-sealing contactor and the running contactor in elevator control systems are gradually becoming electronic. However, the commonly used power supply scheme for the frequency converter in elevator control systems is as follows: the mains power is rectified into a DC bus voltage by the frequency converter's rectifier bridge, and then converted into the required DC power supply by the frequency converter's switching power supply circuit. This makes the frequency converter highly susceptible to the influence of the mains power, especially when the mains power fails, as it cannot achieve the electronic star-sealing function, thus affecting the safety of the elevator.

[0003] There is currently no effective solution to the safety hazards associated with the power supply methods for elevator frequency converters. Summary of the Invention

[0004] This embodiment provides a safety control method for elevator frequency converters, an elevator frequency converter, a control system, and an elevator to address the safety hazards associated with the power supply methods of elevator frequency converters in related technologies.

[0005] In a first aspect, this embodiment provides a safety control method for an elevator frequency converter. The frequency converter includes a switching power supply circuit, an energy storage circuit, a drive module, a control module, and a braking unit. The switching power supply circuit is powered by an independent power source and is used to charge the energy storage circuit and supply power to the drive module, the control module, and the braking unit. The energy storage circuit is used to supply power to the drive module, the control module, and the braking unit when the switching power supply circuit is de-energized. The braking unit is used to connect or disconnect the connection between the frequency converter's DC bus and the braking resistor under the control of the control module. The method includes:

[0006] Detect whether the switching power supply circuit is de-energized;

[0007] When a power outage is detected, the braking unit is controlled to connect the braking resistor and the DC bus to discharge the DC bus.

[0008] In one embodiment, the method further includes:

[0009] The timing begins when the braking unit is connected to the braking resistor and the DC bus.

[0010] When a preset time threshold is reached, the braking unit is controlled to disconnect the braking resistor from the DC bus.

[0011] In one embodiment, the time threshold is determined based on the capacitance of the DC bus and the resistance of the braking resistor.

[0012] In a second aspect, an elevator frequency converter provided in this application includes a switching power supply circuit, an energy storage circuit, a drive module, a control module, and a braking unit. The switching power supply circuit is powered by an independent power source and is used to charge the energy storage circuit and supply power to the drive module, the control module, and the braking unit. The energy storage circuit is used to supply power to the drive module, the control module, and the braking unit when the switching power supply circuit is de-energized. The braking unit is used to connect or disconnect the connection between the frequency converter's DC bus and the braking resistor under the control of the control module. The control module is used to execute the elevator frequency converter safety control method as described in the first aspect above.

[0013] In one embodiment, the frequency converter further includes a control module power supply circuit and a drive module power supply circuit;

[0014] The control module power supply circuit is used to supply power to the control module;

[0015] The power supply circuit for the drive module is used to supply power to the drive module and the braking unit;

[0016] The output terminal of the switching power supply circuit is connected to the energy storage circuit, the drive module power supply circuit, and the control module power supply circuit, respectively, and is used to convert the output voltage of the independent power supply into a first voltage to charge the energy storage circuit and supply power to the drive module power supply circuit and the control module power supply circuit.

[0017] The energy storage circuit has its output terminal connected to the power supply circuit of the drive module and the power supply circuit of the control module, respectively, and is used to supply power to the power supply circuit of the drive module and the power supply circuit of the control module when the switching power supply circuit is de-energized.

[0018] In one embodiment, the energy storage circuit includes a diode D1 and an energy storage capacitor C1;

[0019] The positive terminal of the diode D1 is connected to the switching power supply circuit, and the negative terminal of the diode D1 is connected to one end of the energy storage capacitor C1, the power supply circuit of the driving module, and the power supply circuit of the control module, respectively.

[0020] The other end of the energy storage capacitor C1 is grounded.

[0021] In one embodiment, the frequency converter further includes a control module power supply circuit; the control module power supply circuit includes a first control module power supply circuit and a second control module power supply circuit;

[0022] The power supply circuit of the first control module is connected to the input terminal of the energy storage circuit and is used to supply power to the first control module;

[0023] The power supply circuit for the second control module is connected to the output terminal of the energy storage circuit and is used to supply power to the second control module.

[0024] In one embodiment, the control module includes a detection circuit and a processor. The detection circuit is connected to the input terminal of the switching power supply circuit and is used to send a power-off signal to the processor when a power failure is detected. The braking unit includes a braking switch and a braking switch drive circuit. The braking switch drive circuit is controlled by the processor and drives the braking switch to connect or disconnect the connection between the inverter DC bus and the braking resistor.

[0025] In a third aspect, an embodiment of this application provides a control system including the independent power supply and the braking resistor, as well as the frequency converter described in the second aspect above;

[0026] The braking resistor is connected to the DC bus of the frequency converter through the braking unit.

[0027] In a fourth aspect, an elevator provided in this application includes a control system as described in the third aspect above.

[0028] Compared with related technologies, the elevator inverter safety control method, elevator inverter, control system, and elevator provided in this embodiment include an inverter comprising a switching power supply circuit, an energy storage circuit, a drive module, a control module, and a braking unit. The switching power supply circuit, powered by an independent power source, is used to charge the energy storage circuit and supply power to the drive module, control module, and braking unit. The energy storage circuit supplies power to the drive module, control module, and braking unit when the switching power supply circuit is de-energized. The braking unit, under the control of the control module, connects or disconnects the inverter's DC bus from the braking resistor. The method includes: detecting whether the switching power supply circuit is de-energized; determining that when de-energized, controlling the braking unit to connect the braking resistor. This invention addresses the safety hazards associated with power supply methods for elevator frequency converters by reconstructing the power supply architecture and power-off control method of the frequency converter. It transforms the DC bus power supply, previously dependent on mains power, into an independent power source for the elevator control system. An energy storage circuit is introduced to provide power to the system after a power outage, ensuring the frequency converter continues to operate and effectively implementing the electronic star-sealing function. Furthermore, the safety control method of this application drives a braking resistor to connect to the DC bus of the frequency converter upon detecting a power outage, enabling rapid discharge of the DC bus. This avoids the safety hazard of electric shock to maintenance personnel caused by the slow voltage drop of the DC bus after a power outage due to the bus capacitance.

[0029] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0030] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0031] Figure 1 This is a circuit diagram of a frequency converter provided in one embodiment of this application;

[0032] Figure 2 This is a circuit structure diagram of the power supply circuit for the control module in a frequency converter provided in an embodiment of this application;

[0033] Figure 3 This is a circuit structure diagram of the power supply circuit of the drive module in a frequency converter provided in an embodiment of this application;

[0034] Figure 4 This is a circuit diagram of a frequency converter provided in another embodiment of this application;

[0035] Figure 5 This is a flowchart of a safety control method for an elevator frequency converter provided in an embodiment of this application;

[0036] Figure 6 This is a flowchart of a braking unit shutting down according to an embodiment of this application. Detailed Implementation

[0037] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0038] Unless otherwise defined, the technical or scientific terms used in this application shall have the general meaning understood by one of ordinary skill in the art to which this application pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these” used in this application do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to these processes, methods, products, or devices. Words such as “connected,” “linked,” and “coupled” used in this application are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. “Multiple” used in this application refers to two or more. “And / or” describes the relationship between related objects, indicating that three relationships may exist; for example, “A and / or B” can represent: A alone, A and B simultaneously, and B alone. Normally, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," "third," etc., used in this application are merely to distinguish similar objects and do not represent a specific order of objects.

[0039] The method embodiment provided in this example can be executed in the frequency converter of an elevator.

[0040] In some embodiments, an elevator frequency converter includes a switching power supply circuit, an energy storage circuit, a drive module, a control module, and a braking unit. The switching power supply circuit, powered by an independent power source, is used to charge the energy storage circuit and supply power to the drive module, control module, and braking unit. The energy storage circuit supplies power to the drive module, control module, and braking unit when the switching power supply circuit is de-energized. The braking unit, under the control of the control module, connects or disconnects the connection between the frequency converter's DC bus and the braking resistor. The control module executes a safety control method for the elevator frequency converter.

[0041] Specifically, the independent power supply can be a switching power supply box installed in the control system, which converts the mains power into low-voltage DC power input to the switching power supply circuit.

[0042] In related technologies, a frequency converter includes a DC bus connected to the mains power, a switching power supply circuit, a control module, and a drive module. The mains power is rectified into a DC bus voltage by the frequency converter's rectifier bridge, and then converted into the required DC power supply by the frequency converter's switching power supply circuit to power the control module and drive module. The control module includes a main control circuit, and the drive module includes power switching transistors and a drive circuit that drives the power switching transistors. The drive circuit, controlled by the main control circuit, generates drive signals to drive the corresponding power switching transistors, realizing the frequency converter's rectification and inversion. Therefore, the frequency converter's power supply is greatly affected by the mains power. Once the mains power fails, both the control module and drive module will lose power, causing the electronic star-sealing function to fail and affecting the elevator's safety.

[0043] This embodiment introduces an independent power supply, changing the switching power supply circuit from being powered by the DC bus to being powered by an independent power supply. An energy storage circuit is installed at the output of the switching power supply circuit. On the one hand, since the independent power supply is connected to the mains power, the switching power supply circuit is unaffected by mains power fluctuations through the conversion of the mains power by the independent power supply. On the other hand, even if the mains power fails, the energy storage circuit can continue to supply power, ensuring that the drive module and control module are unaffected by the power outage, effectively realizing the electronic star-sealing function and improving the elevator's safety performance. However, because the inverter can still operate during a power outage, and the voltage on the DC bus decreases very slowly due to the presence of bus capacitors, there is a significant risk of electric shock if elevator commissioning or maintenance personnel work at this time, creating a safety hazard. Therefore, this application proposes a safety control method for an elevator inverter, including the following steps:

[0044] Check if the switching power supply circuit is de-energized;

[0045] When a power outage is detected, the control braking unit connects the braking resistor and the DC bus to discharge the DC bus.

[0046] Specifically, the braking resistor is externally connected to the frequency converter and is connected to the DC bus through the braking unit. When the control module determines that there is a power failure, it controls the braking unit to operate, causing the braking resistor to connect to the DC bus, thereby rapidly discharging the bus voltage.

[0047] In some of these embodiments, such as Figure 4 As shown, the control module includes a detection circuit and a processor. The detection circuit is connected to the input terminal of the switching power supply circuit and is used to send a power-off signal to the processor when a power failure is detected. The braking unit includes a brake switch and a brake switch drive circuit. The brake switch drive circuit is controlled by the processor and drives the brake switch to connect or disconnect the connection between the inverter DC bus and the braking resistor.

[0048] For example, if the processor is a DSP processor and the brake switch is an IGBT, then the brake switch drive circuit is correspondingly an IGBT drive circuit. The specific circuit structure can utilize existing technology.

[0049] The elevator frequency converter and its safety control method provided in this embodiment change the power supply of the frequency converter to a low-voltage DC power supply, such as DC+24V, directly connected to an independent power supply in the control system. The DC+24V is then stepped down to the required DC power supply to power the entire system, solving the problem of being affected by the mains power grid and reducing costs. The power supply section of the frequency converter is designed with an energy storage function. First, the power supply is connected to the frequency converter from the DC+24V in the control system. The frequency converter steps down the DC+24V voltage to DC+15V through a switching power supply circuit. When DC+15V is established, it begins to supply power to the entire frequency converter system and simultaneously begins charging the energy storage circuit until it reaches DC+15V. When a power grid outage occurs, the D in the control system... The +24V power supply will also fail. At this time, the inverter's power supply will switch from the independent +24V power supply to the +15V power supply of the energy storage circuit. Simultaneously, the detection circuit in the control module, which is specifically designed to detect the +24V power supply, will output a +24V power failure signal to the DSP processor. Then, the DSP processor will control the IGBT brake switch to open, connecting the brake resistor in the control system to the inverter's DC bus. This allows the inverter bus capacitor voltage to be quickly released through the brake resistor. The entire process reduces the bus power failure time from several minutes to within a few hundred milliseconds, instantly reducing the bus voltage from several hundred volts to tens of volts or even lower. This achieves the function of quickly releasing the bus capacitor voltage after a power failure, maximizing the protection of the operational safety of on-site personnel.

[0050] In some of these embodiments, such as Figure 1 As shown, it provides a structural block diagram of the frequency converter. The frequency converter also includes a power supply circuit for the drive module and a power supply circuit for the control module;

[0051] The control module power supply circuit is used to supply power to the control module.

[0052] The drive module power supply circuit is used to supply power to the drive module and the braking unit.

[0053] The switching power supply circuit has its input terminal connected to an independent power supply and its output terminal connected to an energy storage circuit, a drive module power supply circuit, and a control module power supply circuit, respectively. It is used to convert the output voltage of the independent power supply into a first voltage to charge the energy storage circuit and to supply power to the drive module power supply circuit and the control module power supply circuit.

[0054] The energy storage circuit has its output terminals connected to the power supply circuits of the drive module and the control module, respectively, and is used to supply power to the power supply circuits of the drive module and the control module when the switching power supply circuit is de-energized.

[0055] Specifically, the input terminal of the switching power supply circuit is connected to an independent power source; the input to the switching power supply circuit is the DC voltage output from the independent power source. The independent power source is positioned between the mains power and the switching power supply circuit, converting the mains power into DC power. The output terminal of the switching power supply circuit is connected to the energy storage circuit, the drive module power supply circuit, and the control module power supply circuit, respectively. The switching power supply circuit converts the DC power output voltage into a first voltage to charge the energy storage circuit and to supply power to the drive module power supply circuit and the control module power supply circuit. Since the mains voltage varies in different regions and at different times, the corresponding switching power supply circuit can be adjusted according to the different mains power conditions.

[0056] The energy storage circuit stores electrical energy while the switching power supply circuit is operating normally (powered by an independent power source connected to the mains, charging the energy storage circuit with the first voltage output from the switching power supply circuit). After the independent power source is de-energized, the stored energy powers the drive module power supply circuit and the control module power supply circuit. The control module power supply circuit powers the control module to ensure its normal operation. The drive module power supply circuit powers the drive module and the braking unit to ensure the normal operation of the electronic star-sealing function. The energy storage circuit includes, but is not limited to, external batteries, emergency DC power supplies, and circuits composed of energy storage capacitors and auxiliary circuits. The specific form of the energy storage circuit can be selected based on the power requirements of subsequent devices in the application scenario, and there are no restrictions on this.

[0057] Those skilled in the art will understand that Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the terminal described above. For example, the terminal may also include components that are larger than... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown are illustrated.

[0058] In this embodiment, the elevator's frequency converter includes a switching power supply circuit, an energy storage circuit, a drive module power supply circuit, and a control module power supply circuit. The switching power supply circuit has its input terminal connected to an independent power supply, and its output terminal connected to the energy storage circuit, the drive module power supply circuit, and the control module power supply circuit, respectively. It is used to convert the input voltage of the independent power supply into a first voltage to charge the energy storage circuit and to supply power to the drive module power supply circuit and the control module power supply circuit. The energy storage circuit has its output terminal connected to the drive module power supply circuit and the control module power supply circuit, respectively. It is used to supply power to the drive module power supply circuit and the control module power supply circuit when the switching power supply circuit is de-energized. This solves the problem in related technologies that the system is greatly affected by the mains power and cannot achieve the electronic star-sealing function when the mains power is de-energized. The independent power supply reduces the impact of the mains power, and the cooperation of the energy storage circuit, the drive module power supply circuit, and the control module power supply circuit enables delayed power supply after a power outage, thereby ensuring the normal operation of the electronic star-sealing function.

[0059] The following is a detailed description of each of the above components:

[0060] In some of these embodiments, the energy storage circuit includes a diode D1 and an energy storage capacitor C1;

[0061] The positive terminal of diode D1 is connected to the switching power supply circuit, and the negative terminal of diode D1 is connected to one end of the energy storage capacitor C1, the power supply circuit of the drive module, and the power supply circuit of the control module, respectively.

[0062] The other end of the energy storage capacitor C1 is grounded.

[0063] Specifically, the energy storage capacitor can be a supercapacitor (also known as an electrochemical capacitor or electric double-layer capacitor), a high-performance energy storage element that falls between traditional capacitors and batteries. Diode D1 enables unidirectional conduction to ensure the correct current flow: switching power supply circuit - energy storage circuit - control module power supply circuit / drive module power supply circuit. Current cannot flow from the energy storage circuit to the switching power supply circuit; thus ensuring that the drive module and control module have sufficient power to operate for the predetermined time, further improving the safety of elevator operation.

[0064] In some of these embodiments, in order to smooth the charging and discharging process of the energy storage capacitor C1, the energy storage circuit also includes a resistor R1 and a diode D2;

[0065] Resistor R1 is connected between the negative terminal of diode D1 and energy storage capacitor C1. Diode D2 is connected in parallel across resistor R1. The negative terminal of diode D2 is connected to the negative terminal of diode D1. The positive terminal of diode D2 is connected to energy storage capacitor C1.

[0066] In this configuration, resistor R1 and diode D2 are connected in parallel to provide a controllable bypass path for the current. The specific parameters of resistor R1 and diode D2 can be set according to the application scenario and are not limited thereto.

[0067] When the mains power is normal, the independent power supply provides normal power to the switching power supply circuit, for example, outputting a DC+24V voltage. After receiving the DC+24V voltage, the switching power supply circuit starts operating, outputting DC+15V, DC-15V, etc. Simultaneously, the DC+15V power supply is connected to the energy storage capacitor C1 through the anti-reverse diode D1, charging the energy storage capacitor C1. As the voltage across capacitor C1 approaches DC+15V, charging gradually stops. When a power outage occurs, the input voltage of the switching power supply also drops, followed by the output DC+24V voltage. The inverter's switching power supply circuit ceases operation, and the DC+15V, DC-15V, etc., power supplies are lost. At this time, the voltage across the energy storage capacitor C1 is higher than the DC+15V voltage output by the inverter's switching power supply circuit. Therefore, the power supply to the control module power supply circuit and the drive module power supply circuit is switched to the energy storage capacitor C1. Thus, through the energy storage circuit design of this embodiment, the power supply operation will automatically resume when the mains power is interrupted.

[0068] In some of these embodiments, such as Figure 2 As shown, the power supply circuit of the control module includes a first control module power supply circuit and a second control module power supply circuit.

[0069] The power supply circuit for the first control module is connected to the input terminal of the energy storage circuit and is used to supply power to the first control module.

[0070] The power supply circuit for the second control module is connected to the output terminal of the energy storage circuit and is used to supply power to the second control module.

[0071] To further extend the power supply time of the energy storage circuit, the control module power supply circuit is configured as two separate circuits: a first control module power supply circuit and a second control module power supply circuit. The energy storage circuit only supplies power to the second control module power supply circuit.

[0072] The first control module power supply circuit is connected to the input terminal of the energy storage circuit and is used to supply power to the first control module. The first control module is an electronic device that can be immediately de-energized after a power outage, including but not limited to fan circuits, human-machine interaction circuits, relay control circuits, etc. Specifically, the first control module power supply circuit can convert a first voltage into a second voltage; under the second voltage, the first control module works normally; therefore, when the power is off, the first control module immediately stops working.

[0073] The power supply circuit for the second control module is connected to the output of the energy storage circuit and is used to power the second control module. The second control module is an electronic device that needs to delay power-off after a power outage, including but not limited to detection circuits and processors. Specifically, the power supply circuit for the second control module can convert the first voltage into a third voltage. Under the third voltage, the second control module operates normally. Therefore, when the power is lost, the energy storage circuit provides power to enable the second control module to continue working for a certain period of time, ensuring the elevator safely reaches the landing position to avoid entrapment and to eliminate the safety hazard of electric shock caused by bus capacitance after a power outage. The specific parameters such as the first voltage, second voltage, and third voltage can be determined by the application scenario and are not limited thereto.

[0074] For example, the input voltage of the switching power supply circuit is DC19V~DC36V, the first voltage is DC15V, and the second and third voltages are both DC5V.

[0075] In some embodiments, the power supply circuit of the first control module includes a first conversion unit and a first LRC module;

[0076] The first conversion unit is connected to the switching power supply circuit and the first LRC module respectively, and is used to convert the first voltage into the second voltage.

[0077] The first LRC module is used to filter the second voltage.

[0078] Specifically, the first conversion unit is mainly used to convert the first voltage into the second voltage. It can be composed of a field-effect transistor, a conversion chip, and corresponding peripheral circuits (including diodes, etc.). After the field-effect transistor is turned on, the first voltage is converted into the second voltage under the action of the conversion chip and its peripheral circuits.

[0079] The first LRC module filters the second voltage by periodically exchanging electromagnetic energy between an inductor and a capacitor, and by controlling the damping effect of a resistor. It includes an inductor L1, a resistor R11, and a capacitor C11. One end of the inductor L1 is connected to the first conversion unit, and the other end of the inductor L1 is connected to one end of the capacitor C11 and one end of the resistor R11. The other ends of the capacitor C11 and the other ends of the resistor R11 are grounded.

[0080] This embodiment avoids overshoot, improves transient stability, and provides a stable operating voltage for the first control module.

[0081] In some of these embodiments, the power supply circuit for the second control module includes a second conversion unit and a second LRC module;

[0082] The second conversion unit is connected to the energy storage circuit and the second LRC module respectively, and is used to convert the first voltage into the third voltage.

[0083] The second LRC module is used to filter the third voltage.

[0084] Specifically, the second conversion unit is mainly used to convert the first voltage into the third voltage. It can be composed of a field-effect transistor, a conversion chip, and corresponding peripheral circuits (including diodes, etc.). After the field-effect transistor is turned on, the first voltage is converted into the third voltage under the action of the conversion chip and its peripheral circuits.

[0085] The second LRC module filters the third voltage by periodically exchanging electromagnetic energy between an inductor and a capacitor, and by controlling the damping effect of a resistor. It includes an inductor L2, a resistor R12, and a capacitor C12. One end of inductor L2 is connected to the first conversion unit, and the other end of inductor L2 is connected to one end of capacitor C12 and one end of resistor R12. The other ends of capacitor C12 and resistor R12 are grounded.

[0086] This embodiment avoids overshoot, improves transient stability, and provides a stable operating voltage for the second control module.

[0087] Furthermore, the power supply circuits for the first and second control modules are made to be the same, thereby simplifying the circuit structure and reducing hardware costs.

[0088] In some embodiments, the drive module power supply circuit is connected to the energy storage circuit and is used to convert the first voltage into a fourth voltage while the energy storage circuit maintains power supply.

[0089] Specifically, the drive module power supply circuit, located after the energy storage circuit, is primarily responsible for providing multiple stable fourth voltages to the subsequent drive module and braking unit. For example, if four 24V DC voltages are required, the drive module power supply circuit can convert the first voltage into four 24V fourth voltages and output them to the subsequent circuits to ensure their normal operation. The drive module includes an IGBT drive circuit, and the braking switch includes a braking IGBT. The IGBT drive circuit is used to drive the operation of each IGBT, including the braking IGBT.

[0090] The power supply circuit of the drive module can be composed of relevant power supply chips and peripheral circuits, or it can be other forms of circuit structure, and there are no restrictions on this.

[0091] In some of these embodiments, such as Figure 3 As shown, the power supply circuit of the drive module includes a transformer, a full-bridge inverter circuit connected to the primary side of the transformer, and a multi-channel rectifier output circuit connected to the secondary side of the transformer; the power supply circuit of the drive module is used to convert the first voltage into multiple fourth voltages.

[0092] Specifically, the full-bridge inverter circuit consists of four power MOSFETs; a transformer is used for isolation; and a multi-channel rectifier output circuit is used to power multiple drive modules. In this embodiment, the fourth voltage is DC24V.

[0093] This embodiment achieves safe isolation, provides precise power supply for multiple IGBT drive circuits, and has anti-interference capabilities.

[0094] In addition, in conjunction with the frequency converter provided in the above embodiments, a control system can also be provided in this embodiment to achieve the same result. The control system includes an independent power supply, a braking resistor, and the frequency converter of any of the above embodiments.

[0095] An independent power supply is connected to the mains power and is used to convert the mains power into DC power to supply power to the switching power supply circuit of the frequency converter.

[0096] The braking resistor is connected to the DC bus of the frequency converter through the braking unit.

[0097] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated in this embodiment.

[0098] It should be noted that the above modules can be functional modules or program modules, and can be implemented through software or hardware. For modules implemented through hardware, the above modules can reside in the same processor; or the above modules can be located in different processors in any combination.

[0099] In some of these embodiments, such as Figure 4 As shown, the control module includes a detection circuit and a processor; the braking unit includes a brake switch and a brake switch drive circuit.

[0100] The detection circuit is connected to the input terminal of the switching power supply circuit and the processor, respectively, and is used to detect whether the input terminal of the switching power supply circuit is de-energized and obtain a detection signal.

[0101] The processor, connected to the brake switch drive circuit, is used to control the brake switch drive circuit to generate a drive signal for the brake switch when the switching power supply circuit is de-energized based on the detection signal.

[0102] The brake switch, connected to the brake switch drive circuit, is used to control the two ends of the brake resistor connected in parallel to the DC bus of the frequency converter based on the drive signal, so as to quickly discharge the DC bus.

[0103] In this system, both the independent power supply and the inverter's DC bus are connected to the mains power. The braking resistor, controlled by the braking switch, is connected in parallel across the inverter's DC bus to rapidly discharge the DC bus. The specific control process is detailed in the following implementation example and will not be repeated here.

[0104] Specifically, the brake switch can be connected in series or in parallel with the brake resistor to control whether the brake resistor is connected to both ends of the DC bus.

[0105] In some of these embodiments, based on the above structure, the following are provided: Figure 5 A flowchart of the safety control method for elevator frequency converters, such as... Figure 5 As shown, the process includes the following steps:

[0106] S210, detects whether the switching power supply circuit is de-energized.

[0107] Specifically, the detection circuit detects whether the DC power supply is cut off and obtains a detection signal.

[0108] S220, when a power failure is detected, controls the braking unit to connect the braking resistor and the DC bus to discharge the DC bus.

[0109] Specifically, the processor determines when the switching power supply circuit is de-energized based on the detection signal, and controls the automatic switch drive circuit to generate a drive signal for the brake switch. Through the brake switch, the brake resistor is connected to both ends of the DC bus of the frequency converter based on the drive signal to quickly discharge the DC bus.

[0110] By coordinating the detection circuit, processor, brake switch drive circuit, and brake switch, rapid discharge of the DC bus can be achieved, thereby avoiding the safety hazard of electric shock.

[0111] It should be noted that the detection circuit, processor, brake switch drive circuit, and brake switch can be implemented using relevant chips and their peripheral circuits or related electronic devices; there are no limitations on this. The structure of the inverter in this embodiment and... Figure 1 The frequency converters can be used in combination. For example: in this embodiment, the drive module and brake switch drive circuit of the frequency converter are... Figure 1 The inverter operates under the fourth voltage provided by the power supply circuit of the drive module.

[0112] The detection circuit is connected to the input of the switching power supply circuit. It detects the output voltage of the independent power supply to determine whether there is a power outage, thus generating a detection signal. For example, if the output voltage is much lower than the normal voltage value, it is considered that there is a power outage, and a low-level detection signal is generated; otherwise, a high-level detection signal is generated. This signal is transmitted to the processor, which can then determine whether the independent power supply is disconnected based on the high or low level signal, and thus generate a control signal to control the braking unit. The control signal depends on the specific form of the braking switch and can be either a digital signal or an analog signal; there is no restriction on this.

[0113] Normally, the brake switch would also lose power and become inoperable when the independent power supply is cut off. However, in this embodiment, the energy storage circuit provides power when the switching power supply circuit is cut off, which can extend the working time of the brake switch. Under the control of the drive signal, the braking resistor is connected to both ends of the DC bus of the frequency converter to quickly discharge the DC bus, thereby solving the problem of electric shock safety hazards caused by the slow voltage drop of the bus and avoiding the safety hazard of electric shock.

[0114] In related technologies, mains power is rectified into DC bus power by the rectifier bridge of the frequency converter, and then converted into the required DC power supply by the switching power supply circuit of the frequency converter to power the entire elevator control system. Currently, when frequency converters are used in conjunction with electronic elevator control systems, the voltage drop on the bus is slow after the frequency converter is powered off due to the bus capacitance, posing a safety hazard of electric shock. In this embodiment, a detection circuit detects whether the DC power supply is interrupted, obtaining a detection signal. A processor determines when the DC power supply is interrupted based on the detection signal and generates a drive signal for the brake switch. The brake switch, based on the drive signal, controls the braking resistor to be connected in parallel across the DC bus of the frequency converter, rapidly discharging the DC bus. This solves the problem of slow voltage drop on the bus, leading to a safety hazard of electric shock, in related technologies. After power failure, the energy provided by the energy storage circuit keeps the brake switch active, thereby outputting a drive signal to drive the braking resistor in parallel across the DC bus of the frequency converter, achieving rapid discharge of the DC bus and thus avoiding the safety hazard of electric shock.

[0115] It should also be noted that in some embodiments, the mains power is connected to the frequency converter, which can obtain 24V DC power through an independent power supply. This DC power is converted into 15V DC (first voltage) by a switching power supply circuit and output to power the energy storage circuit and the first control module power supply circuit. The first control module power supply circuit converts the first voltage into a second voltage; the second voltage is used to provide the operating voltage for the first control module in the elevator. The energy storage capacitor in the energy storage circuit is continuously charged to store electrical energy. When the mains power is normal, the DC power supply to the second control module (which can be a detection circuit, processor, etc.) in the elevator is provided by the second control module power supply circuit. When the mains power is lost, the electrical energy stored in the energy storage capacitor powers the second control module in the elevator, and the first control module power supply circuit and the first control module are directly de-energized.

[0116] In some of these embodiments, such as Figure 6 As shown, the safety control method for elevator frequency converters also includes the following steps:

[0117] Step S610: Start timing when the braking unit is connected to the braking resistor and the DC bus;

[0118] In step S620, when the preset time threshold is reached, the braking resistor is disconnected by the braking switch under the control of the processor.

[0119] Specifically, the time threshold is preset and can be set by the experimental test.

[0120] Preferably, the time threshold is determined based on the capacitance of the DC bus and the resistance of the braking resistor.

[0121] Because the capacitance values ​​of the bus capacitors differ across power ratings, with higher-power bus capacitors having larger capacitance values, the capacitance directly affects the discharge rate. The time required for the capacitor to discharge is calculated using the capacitance value and the resistance value of the braking resistor, with a time threshold set to be greater than or equal to the discharge time required for that capacitor. This conserves energy from the energy storage circuit used to release the bus voltage.

[0122] Before the preset time threshold is reached, the processor controls the brake switch drive circuit, such as the IGBT drive circuit, to generate a drive signal to drive the brake switch, such as the brake IGBT, to open, so that the brake resistor is connected in parallel to the DC bus of the frequency converter to quickly discharge the DC bus; then when the preset time threshold is reached, it can be considered that the DC bus has completed discharging. At this time, the processor re-controls the generation of drive signals to drive the brake IGBT to close, thereby restoring the circuit state and preparing for normal use in the future.

[0123] During the switch to energy storage circuit power supply, the inverter's detection circuit detects a power outage of the input DC+24V voltage and sends high and low level signals to the DSP processor. The DSP processor, after filtering, confirms the DC+24V voltage drop and begins driving the inverter's braking unit to open the braking IGBT. This causes the braking resistor in the elevator control system to be connected to the inverter's bus. The several hundred volts on the bus capacitor are rapidly released to tens of volts or even lower through the braking resistor. During this process, the DSP processor presets the opening time, which varies depending on the power range, as the bus capacitor capacitance differs for different power ranges. Higher power inverters typically have larger bus capacitor capacitances, which directly affect the discharge speed. When the braking unit opening time reaches the preset value, the DSP processor closes the braking unit, completing the rapid release of the bus capacitor voltage. This process is completed before the energy storage capacitor reaches the preset voltage, ensuring that the power supply circuits for the control module and drive module are functioning normally throughout the entire process.

[0124] Further energy storage circuits can be equipped with multiple energy storage capacitors connected in parallel to improve operational reliability.

[0125] Furthermore, in conjunction with the frequency converter and related methods provided in the above embodiments, this embodiment can also provide an elevator to achieve the same result. The elevator includes the aforementioned control system.

[0126] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated in this embodiment.

[0127] It should be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. All other embodiments derived by those skilled in the art based on the embodiments provided in this application without inventive effort are within the scope of protection of this application.

[0128] Obviously, the accompanying drawings are merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar situations based on these drawings without any creative effort. Furthermore, it is understood that although the work done in this development process may be complex and lengthy, for those skilled in the art, certain design, manufacturing, or production modifications made based on the technical content disclosed in this application are merely conventional technical means and should not be considered as insufficient disclosure of this application.

[0129] The term "embodiment" in this application refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply that it is mutually exclusive with or independent of other embodiments. It will be clearly or implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0130] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. A safety control method for an elevator frequency converter, characterized in that, The frequency converter includes a switching power supply circuit, an energy storage circuit, a drive module, a control module, and a braking unit; the switching power supply circuit is powered by an independent power source and is used to charge the energy storage circuit and supply power to the drive module, the control module, and the braking unit; the energy storage circuit is used to supply power to the drive module, the control module, and the braking unit when the switching power supply circuit is de-energized. The braking unit is used to connect or disconnect the DC bus of the frequency converter from the braking resistor under the control of the control module; the method includes: Detect whether the switching power supply circuit is de-energized; When a power outage is detected, the braking unit is controlled to connect the braking resistor and the DC bus to discharge the DC bus.

2. The elevator frequency converter safety control method according to claim 1, characterized in that, The method further includes: The timing begins when the braking unit is connected to the braking resistor and the DC bus. When a preset time threshold is reached, the braking unit is controlled to disconnect the braking resistor from the DC bus.

3. The elevator frequency converter safety control method according to claim 2, characterized in that, The time threshold is determined based on the capacitance of the DC bus and the resistance of the braking resistor.

4. An elevator frequency converter, characterized in that, The system includes a switching power supply circuit, an energy storage circuit, a drive module, a control module, and a braking unit. The switching power supply circuit is powered by an independent power source and is used to charge the energy storage circuit and supply power to the drive module, the control module, and the braking unit. The energy storage circuit supplies power to the drive module, the control module, and the braking unit when the switching power supply circuit is de-energized. The braking unit, under the control of the control module, connects or disconnects the connection between the inverter's DC bus and the braking resistor. The control module is used to execute the elevator inverter safety control method as described in any one of claims 1 to 3.

5. The elevator frequency converter according to claim 4, characterized in that, The frequency converter also includes a control module power supply circuit and a drive module power supply circuit; The control module power supply circuit is used to supply power to the control module; The power supply circuit for the drive module is used to supply power to the drive module and the braking unit; The output terminal of the switching power supply circuit is connected to the energy storage circuit, the drive module power supply circuit, and the control module power supply circuit, respectively, and is used to convert the output voltage of the independent power supply into a first voltage to charge the energy storage circuit and supply power to the drive module power supply circuit and the control module power supply circuit. The energy storage circuit has its output terminal connected to the power supply circuit of the drive module and the power supply circuit of the control module, respectively, and is used to supply power to the power supply circuit of the drive module and the power supply circuit of the control module when the switching power supply circuit is de-energized.

6. The elevator frequency converter according to claim 5, characterized in that, The energy storage circuit includes a diode D1 and an energy storage capacitor C1; The positive terminal of the diode D1 is connected to the switching power supply circuit, and the negative terminal of the diode D1 is connected to one end of the energy storage capacitor C1, the power supply circuit of the driving module, and the power supply circuit of the control module, respectively. The other end of the energy storage capacitor C1 is grounded.

7. The elevator frequency converter according to claim 5, characterized in that, The power supply circuit for the control module includes a first power supply circuit for the control module and a second power supply circuit for the control module. The power supply circuit of the first control module is connected to the input terminal of the energy storage circuit and is used to supply power to the first control module; The power supply circuit for the second control module is connected to the output terminal of the energy storage circuit and is used to supply power to the second control module.

8. The elevator frequency converter according to claim 4, characterized in that, The control module includes a detection circuit and a processor. The detection circuit is connected to the input terminal of the switching power supply circuit and is used to send a power-off signal to the processor when a power failure is detected. The braking unit includes a braking switch and a braking switch drive circuit. The braking switch drive circuit is controlled by the processor and drives the braking switch to connect or disconnect the connection between the inverter DC bus and the braking resistor.

9. A control system, characterized in that, Includes the independent power supply and the braking resistor, and the elevator frequency converter as described in any one of claims 4 to 8; The braking resistor is connected to the DC bus of the frequency converter through the braking unit.

10. An elevator, characterized in that, Includes the control system as described in claim 9.

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