Power conversion circuit and electric device

Abstract

The application relates to a power conversion circuit and a power utilization device. The power conversion circuit comprises a first conversion circuit, a one-way switch circuit and a second conversion circuit. An input end of the first conversion circuit is connected to a power supply to convert a voltage provided by the power supply into a first power supply voltage. An input end of the one-way switch circuit is connected to a backup power supply, and an output end of the one-way switch circuit is connected to an output end of the first conversion circuit. The one-way switch circuit is turned on when the voltage at the output end of the first conversion circuit is lower than a preset voltage threshold, and is turned off when the voltage at the output end of the first conversion circuit is greater than or equal to the preset voltage threshold. Input ends of the second conversion circuit are respectively connected to the output end of the first conversion circuit and the output end of the one-way switch circuit, and an output end of the second conversion circuit is connected to a first load. The second conversion circuit is used for converting the first power supply voltage or a voltage provided by the backup power supply into a second power supply voltage. The power conversion circuit does not need complex control logic when switching the backup power supply, thereby reducing the design complexity and implementation cost.

Description

Technical Field

[0001] This application relates to the field of electronic circuit technology, and in particular to a power conversion circuit and an electrical device. Background Technology

[0002] In the power supply design of elevators and other electrical equipment, on the one hand, the power circuit needs to convert the mains power to meet the power supply requirements of various devices such as frequency converters, fans, and relays, thereby ensuring the normal operation of the equipment. On the other hand, to improve the reliability of the equipment, a backup power supply is also set up. When the control system detects a power outage, it quickly switches to the backup power supply to ensure that the equipment can continue to operate for a certain period of time in case of an emergency, avoiding the safety hazards and inconvenience caused by direct shutdown due to power outage.

[0003] However, the current control method has complex control logic, requiring the control system to accurately monitor the mains power status and promptly switch to backup power when the mains power fails. If a backup power source is connected when the mains power is normal, mutual interference may occur between the mains power and the backup power source, resulting in inaccurate output voltage. Such voltage fluctuations or anomalies directly affect the stable operation of electrical equipment, leading to low operational reliability. For example, it may cause instability in the inverter's output frequency, thereby affecting the elevator's operating speed and smoothness, and reducing the elevator's operational reliability. Utility Model Content

[0004] Therefore, it is necessary to provide a power conversion circuit and electrical equipment that can improve the operational reliability of electrical equipment.

[0005] A power conversion circuit, comprising:

[0006] A first conversion circuit, wherein the input terminal of the first conversion circuit is used to connect to a power supply, and the first conversion circuit is used to convert the voltage provided by the power supply into a first power supply voltage;

[0007] A one-way switch circuit is provided, wherein the input terminal of the one-way switch circuit is used to connect to a backup power supply, and the output terminal of the one-way switch circuit is connected to the output terminal of the first conversion circuit. The one-way switch circuit is turned on when the voltage at the output terminal of the first conversion circuit is lower than a preset voltage threshold, and is turned off when the voltage at the output terminal of the first conversion circuit is greater than or equal to the preset voltage threshold.

[0008] The second conversion circuit has its input terminals connected to the output terminals of the first conversion circuit and the unidirectional switch circuit, respectively. The output terminal of the second conversion circuit is used to connect to the first load. The second conversion circuit is used to convert the first power supply voltage or the voltage provided by the backup power supply into a second power supply voltage that matches the first load.

[0009] In one embodiment, the unidirectional switching circuit includes a power switching diode; the anode of the power switching diode serves as the input terminal of the unidirectional switching circuit, and the cathode of the power switching diode serves as the output terminal of the unidirectional switching circuit; the preset voltage threshold is determined based on the parameters of the backup power supply and the power switching diode.

[0010] In one embodiment, the first conversion circuit includes:

[0011] The first transformer, wherein the first end of the primary winding of the first transformer is used to connect to the power supply;

[0012] The first switching transistor has its first terminal connected to the second end of the primary winding of the first transformer, its second terminal connected to the power supply, and its control terminal used to receive a first control signal.

[0013] The first rectifier output unit is connected to the secondary winding of the first transformer, the input terminal of the second conversion circuit, and the output terminal of the unidirectional switch circuit. The first rectifier output unit is used to output the first power supply voltage.

[0014] In one embodiment, the second conversion circuit includes:

[0015] The second transformer has its primary winding connected at the first end to the output of the first conversion circuit and the output of the unidirectional switching circuit.

[0016] The second switching transistor has its first terminal connected to the second end of the primary winding of the second transformer, its second terminal connected to the output terminal of the first conversion circuit, and its control terminal used to receive a second control signal.

[0017] The second rectifier output unit is connected to the secondary winding of the second transformer and the first load, and is used to output the second power supply voltage to the first load.

[0018] In one embodiment, there are multiple secondary windings of the second transformer and multiple second rectifier output units. Each secondary winding of the second transformer is connected to a corresponding second rectifier output unit, and the second rectifier output unit is also used to be connected to a corresponding first load.

[0019] In one embodiment, there are multiple second conversion circuits, and the input terminal of each second conversion circuit is connected to the output terminal of the first conversion circuit. The output terminal of each second conversion circuit is used to connect to a corresponding first load.

[0020] In one embodiment, the first load includes a control chip, the power supply terminal of which is connected to the output terminal of one of the second conversion circuits, and the output terminal of which is connected to the control terminals of the first conversion circuit and the remaining second conversion circuits; the control chip is used to control the output state of the first conversion circuit and the remaining second conversion circuits.

[0021] In one embodiment, the output of the first conversion circuit and the output of the unidirectional switch circuit are also used to connect a second load, the second load having a different voltage level than the first load.

[0022] An electrical device includes a backup power supply, a first load, and a power conversion circuit as described above.

[0023] In one embodiment, the electrical equipment is an elevator, the first load includes a frequency converter circuit and a drive control circuit, the drive control circuit is connected to the output terminal of the second conversion circuit in the power conversion circuit, and the second power supply voltage output by the second conversion circuit supplies power to the drive control circuit;

[0024] The drive control circuit is also connected to the frequency converter circuit, and is used to control the operating state of the frequency converter circuit or to perform star-controlled operation on the frequency converter circuit.

[0025] In one embodiment, the drive control circuit includes a drive chip and a control chip, wherein the control chip is connected to the drive chip;

[0026] There are multiple second conversion circuits, and the input terminal of each second conversion circuit is connected to the output terminal of the first conversion circuit. The output terminal of one second conversion circuit is connected to the control chip, and the output terminal of another second conversion circuit is connected to the driver chip.

[0027] In one embodiment, the driving chips are configured as a plurality of them, and the control chip is connected to each of the driving chips;

[0028] One of the output terminals of the second conversion circuit is connected to the control chip, and the output terminals of the remaining second conversion circuits are connected one-to-one with the respective driver chips.

[0029] In one embodiment, the drive control circuit includes a drive chip and a control chip, wherein the control chip is connected to the drive chip;

[0030] The second conversion circuit includes a second transformer and a second rectifier output unit. The second transformer has multiple secondary windings and multiple second rectifier output units. Each secondary winding is connected to a second rectifier output unit to form multiple output circuits. The output terminal of one of the output circuits is connected to the control chip, and the output terminal of another output circuit is connected to the driver chip.

[0031] In one embodiment, the driving chips are configured as a plurality of them, and the control chip is connected to each of the driving chips;

[0032] One of the output circuits is connected to the control chip, and the outputs of the other output circuits are connected one-to-one with the respective driver chips.

[0033] In the aforementioned power conversion circuit and electrical equipment, when the power supply (such as mains power) is normal, the first conversion circuit converts the voltage provided by the power supply to a first power supply voltage, and the second conversion circuit converts the first power supply voltage to a second power supply voltage that matches the first load (such as the frequency converter circuit of an elevator), thus supplying power to the first load. At this time, because the voltage at the output of the first conversion circuit is higher than a preset voltage threshold, the one-way switch circuit is in the open state, and the backup power supply does not work. When the power supply malfunctions (such as a mains power failure), the voltage at the output of the first conversion circuit will drop below the preset voltage threshold. At this time, the one-way switch circuit will conduct, the backup power supply will be connected to the circuit, and the second conversion circuit will convert the voltage introduced by the backup power supply to the second power supply voltage, continuing to supply power to the first load. This power conversion circuit does not require complex control logic when switching backup power, reducing design complexity and implementation cost. At the same time, due to the one-way conduction characteristic of the one-way switch circuit, it effectively prevents problems such as current backflow that may occur at the moment of mains power restoration, further improving the safety of the power conversion circuit and avoiding damage to the backup power supply connected to the power conversion circuit. This improves the operational reliability of elevators and other electrical equipment, avoids safety hazards and inconvenience caused by direct shutdown due to power outages, and provides a strong guarantee for the stable operation of elevators and other equipment. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 This is a schematic diagram of a power conversion circuit module according to one embodiment;

[0036] Figure 2A schematic diagram of a power conversion circuit according to another embodiment;

[0037] Figure 3 This is a schematic diagram of the circuit structure of a power conversion circuit according to one embodiment;

[0038] Figure 4 A schematic diagram of the circuit structure of a power conversion circuit according to another embodiment;

[0039] Figure 5 This is a schematic diagram of a power conversion circuit according to yet another embodiment;

[0040] Figure 6 This is a schematic diagram of a power conversion circuit according to yet another embodiment;

[0041] Figure 7 This is a schematic diagram of some modules of an elevator according to one embodiment;

[0042] Figure 8 This is a schematic diagram of a partial circuit structure of an elevator according to one embodiment;

[0043] Figure 9 This is a schematic diagram of another module of an elevator according to one embodiment. Detailed Implementation

[0044] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0046] It is understood that the terms "first," "second," etc., used herein may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0047] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0048] It is understandable that "at least one" refers to one or more, and "multiple" refers to two or more. "At least a part of an element" refers to part or all of an element.

[0049] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0050] This application provides a power conversion circuit, such as... Figure 1 As shown, the power conversion circuit includes a first conversion circuit 100, a second conversion circuit 200, and a one-way switching circuit 300.

[0051] The input terminal of the first conversion circuit 100 is used to connect to a power supply, and the first conversion circuit 100 is used to convert the voltage provided by the power supply to a first power supply voltage. The input terminal of the one-way switch circuit 300 is used to connect to a backup power supply, and the output terminal of the one-way switch circuit 300 is connected to the output terminal of the first conversion circuit 100. The one-way switch circuit 300 is turned on when the voltage at the output terminal of the first conversion circuit 100 is lower than a preset voltage threshold, and turned off when the voltage at the output terminal of the first conversion circuit 100 is greater than or equal to the preset voltage threshold. The input terminal of the second conversion circuit 200 is connected to the output terminal of the first conversion circuit 100 and the output terminal of the one-way switch circuit 300, respectively. The output terminal of the second conversion circuit 200 is used to connect to a first load; the second conversion circuit 200 is used to convert the first power supply voltage or the voltage provided by the backup power supply to a second power supply voltage that matches the first load.

[0052] The power supply is the main power source for this power conversion circuit. Under normal operating conditions, the first conversion circuit 100 converts the power supply voltage into a first power supply voltage and outputs it to its output terminal. Since the first power supply voltage is greater than a preset voltage threshold, the unidirectional switch circuit 300 is in the open state, and the backup power supply does not participate in power supply. At this time, the second conversion circuit 200 receives the first power supply voltage output by the first conversion circuit 100 and converts it into a second power supply voltage that matches the first load, thus supplying power to the first load.

[0053] When the power supply fails or malfunctions, causing the output voltage of the first conversion circuit 100 to drop below a preset voltage threshold, the one-way switch circuit 300 is activated. The backup power supply voltage is then transmitted to the input of the second conversion circuit 200 via the one-way switch circuit 300. The second conversion circuit 200 converts the voltage provided by the backup power supply into a second power supply voltage, continuing to supply power to the first load and ensuring that the first load can still operate normally when the main power supply fails. The first load can be the elevator's frequency converter circuit or other circuits, and can be specifically configured according to actual conditions.

[0054] The preset voltage threshold needs to be set according to specific circumstances, for example, determined based on the backup power supply voltage and the circuit parameters of the unidirectional switch circuit 300. It is understood that when the main power supply is normal, the first power supply voltage is greater than or equal to the preset voltage threshold to prioritize powering the first load. Furthermore, this allows the unidirectional switch circuit 300 to remain open when the main power supply is normal, preventing the backup power supply from participating in power supply. As an example, if the first power supply voltage is 26V and the backup power supply voltage is 24V when the main power supply is normal, the preset voltage threshold can be between 23V and 24V.

[0055] The method of drawing voltage from the power supply is not limited. For example, power can be drawn from the mains bus, from a half-bus, or from the live wire (L) and neutral wire (N) of the mains power. The mains bus can be the DC bus of the power system in the electrical equipment where the power conversion circuit is located, or the DC bus in the power transmission system, and the half-bus can be the actual connection point of the mains bus. For instance, when this power conversion circuit is applied to an elevator, the elevator's power system converts mains power to DC power, and the first conversion circuit 100 draws power from the DC bus of that power system.

[0056] In the aforementioned power conversion circuit, when the power supply is functioning normally, the first conversion circuit 100 converts the voltage provided by the power supply to a first power supply voltage, and the second conversion circuit 200 converts the first power supply voltage to a second power supply voltage that matches the first load (such as the frequency converter circuit of an elevator), thus supplying power to the first load. At this time, because the voltage at the output of the first conversion circuit 100 is higher than a preset voltage threshold, the one-way switch circuit 300 is in the open state, and the backup power supply does not operate. When the power supply malfunctions, the voltage at the output of the first conversion circuit 100 drops below the preset voltage threshold. At this time, the one-way switch circuit 300 conducts, the backup power supply is connected to the circuit, and the second conversion circuit 200 converts the voltage introduced by the backup power supply to the second power supply voltage, continuing to supply power to the first load. This power conversion circuit eliminates the need for complex control logic when switching the backup power supply, reducing design complexity and implementation costs. Simultaneously, due to the one-way conduction characteristic of the one-way switch circuit 300, problems such as current backflow that may occur at the moment of mains power restoration are effectively prevented, further improving the safety of the power conversion circuit and avoiding damage to the backup power supply connected to the power conversion circuit. This improves the operational reliability of elevators and other electrical equipment, avoids safety hazards and inconvenience caused by direct shutdown due to power outages, and provides a strong guarantee for the stable operation of elevators and other equipment.

[0057] In some embodiments, such as Figure 2 As shown, the output terminals of the first conversion circuit 100 and the unidirectional switch circuit 300 are also used to connect a second load.

[0058] The second load has a different voltage rating than the first load. For example, the second load is matched with a voltage rating of 24-26V, while the first load is matched with a voltage rating of 12V, 9V, 5V, etc.

[0059] In this embodiment, the first conversion circuit 100 and the backup power supply serve as primary power sources, supplying power to the second load and the second conversion circuit 200. The second conversion circuit 200 serves as a secondary power source, outputting a second power supply voltage to power the first load. This allows the first and second loads, with different voltage levels, to operate simultaneously, meeting the voltage requirements of various components in the electrical equipment. In the event of a power supply failure, the system automatically switches to the backup power supply, ensuring the continuous operation of both the first and second loads and improving the power supply reliability of the power conversion circuit.

[0060] In some embodiments, such as Figure 3 As shown, the unidirectional switching circuit 300 includes a power switching diode D1. The anode of the power switching diode D1 serves as the input terminal of the unidirectional switching circuit 300, and the cathode of the power switching diode D1 serves as the output terminal of the unidirectional switching circuit 300.

[0061] In this circuit, when the voltage connected to the first conversion circuit 100 drops to a certain level, its output voltage falls below a preset voltage threshold, triggering the power switching diode D1 to conduct, thus connecting the backup power supply to the circuit. The preset voltage threshold can be determined based on the parameters of the backup power supply and the power switching diode D1. As an example, the preset voltage threshold is equal to the backup power supply voltage minus the forward voltage drop of the power switching diode D1. For instance, if the backup power supply voltage is 24V, the forward voltage drop of the power switching diode D1 is approximately 0.7V, and the preset voltage threshold is approximately 23.3V. In other embodiments, the preset voltage threshold can be set to the backup power supply voltage minus the forward voltage drop of the diode, with a certain margin to cope with voltage fluctuations.

[0062] In this embodiment, power is supplied by a DC bus. When the bus voltage is normal, the first power supply voltage obtained by the first conversion circuit 100 is greater than the backup power supply voltage. That is, the voltage at the cathode of the power switching diode D1 is greater than the voltage at the anode. At this time, the power switching diode D1 is in reverse cutoff state, and the backup power supply cannot be connected to the subsequent circuit. The first power supply voltage directly supplies power to the second load and simultaneously provides input voltage to the second conversion circuit 200. The second conversion circuit 200 converts the first power supply voltage into a second power supply voltage that matches the first load, thus supplying power to the first load.

[0063] When the bus voltage drops due to mains power failure or other reasons, the output voltage of the first conversion circuit 100 decreases. When the first power supply voltage drops below a preset voltage threshold, the difference between the anode voltage (backup power supply voltage) and the cathode voltage (output voltage of the first conversion circuit 100) of the power switching diode D1 meets its forward conduction condition, and the power switching diode D1 conducts. The backup power supply voltage is then transmitted to the input of the second load and the second conversion circuit 200 through the power switching diode D1. At this time, the backup power supply powers the second load, and the second conversion circuit 200 converts the backup power supply voltage to the second power supply voltage to continue powering the first load, ensuring that the first and second loads can still operate normally when the main power supply fails.

[0064] In this embodiment, the unidirectional switch circuit 300 is implemented using a power switching diode D1. The circuit structure is simple and does not require complex control devices such as controllers, resulting in low design complexity and implementation cost. Moreover, due to the unidirectional conduction characteristic of the diode, it can effectively prevent problems such as current backflow that may occur when the mains power is restored and the bus power supply is restored, further improving the safety of the power conversion circuit and avoiding damage to the backup power supply connected to the power conversion circuit.

[0065] In other embodiments, the one-way switch circuit 300 can also be implemented using other devices, such as manual switches, relays, etc., which can be implemented by those skilled in the art according to specific circumstances.

[0066] The circuit structure of the first conversion circuit 100 is not unique. In some embodiments, the first conversion circuit 100 adopts a flyback converter topology. Specifically, the first conversion circuit 100 includes a first transformer T1, a first switching transistor Q1, and a first rectifier output unit 110. The first end of the primary winding of the first transformer T1 is used to connect to a power supply. The first terminal of the first switching transistor Q1 is connected to the second end of the primary winding of the first transformer T1, the second terminal of the first switching transistor Q1 is connected to the power supply, and the control terminal of the first switching transistor Q1 is used to connect to a first control signal. The first rectifier output unit 110 is connected to the secondary winding of the first transformer T1, the input terminal of the second conversion circuit 200, and the output terminal of the unidirectional switching circuit 300, and is used to output a first power supply voltage.

[0067] Specifically, the first end of the primary winding of the first transformer T1 can be connected to the positive terminal of the bus, and the second terminal of the first switching transistor Q1 is connected to the negative terminal of the bus. The first switching transistor Q1 is used to control the switching of current in the primary winding of the first transformer T1, thereby realizing the storage and release of energy.

[0068] The type of the first switching transistor Q1 can be selected according to specific needs. As an example, the first switching transistor Q1 is an NMOS (N-Metal-Oxide-Semiconductor), with the gate as the control electrode, the drain as the first electrode, and the source as the second electrode. The first control signal is generated by a control circuit, which adjusts the on and off times (duty cycle) of the first switching transistor Q1 based on feedback signals such as the output voltage and current of the first rectifier output unit 110, thereby achieving stable control of the output first power supply voltage. Furthermore, the first control signal can also ensure that the output voltage of the first transformer T1 is not lower than a preset voltage threshold by adjusting the duty cycle of the first switching transistor Q1. This allows the first conversion circuit 100 to continuously and stably output the first power supply voltage to the second conversion circuit 200 when the power supply (such as mains power) is operating normally, while simultaneously preventing the backup power supply from being connected when the power supply is normal.

[0069] In some embodiments, the first rectifier output unit 110 includes a first rectifier diode D2 and a first filter capacitor C1. The anode of the first rectifier diode D2 is connected to the first terminal of the secondary winding of the first transformer T1, the cathode of the first rectifier diode D2 is connected to the first terminal of the first filter capacitor C1, and the second terminal of the first filter capacitor C1 is connected to the second terminal of the secondary winding. The two ends of the first filter capacitor C1 are used to connect the input terminal of the second conversion circuit 200 and the cathode of the power switching diode D1. This achieves effective rectification and filtering of the output voltage of the secondary winding of the first transformer T1 to provide a stable and reliable first power supply voltage.

[0070] In this embodiment, the first conversion circuit 100, which adopts a flyback converter topology, achieves effective conversion of the power supply, providing a stable primary power supply for subsequent circuits.

[0071] In other embodiments, the first conversion circuit 100 may also adopt other topologies, such as BUCK circuit, BOOST circuit, forward converter, push-pull circuit, etc.

[0072] The circuit structure of the second conversion circuit 200 is not unique. In some embodiments, the second conversion circuit 200 also adopts a flyback converter topology. Specifically, the second conversion circuit 200 includes a second transformer T2, a second switch Q2, and a second rectifier output unit 210. The first end of the primary winding of the second transformer T2 is connected to the output terminal of the first conversion circuit 100 and the output terminal of the unidirectional switching circuit 300. The first terminal of the second switch Q2 is connected to the second end of the primary winding of the second transformer T2, the second terminal of the second switch Q2 is connected to the output terminal of the first conversion circuit 100, and the control terminal of the second switch Q2 is used to receive a second control signal. The second rectifier output unit 210 is connected to the secondary winding of the second transformer T2 and the first load, and the second rectifier output unit 210 is used to output a second power supply voltage to the first load.

[0073] Specifically, the first terminal of the primary winding of the second transformer T2 can be connected to the cathode of the first rectifier diode D2, and the second terminal of the second switching transistor Q2 is connected to the second terminal of the first filter capacitor C1. The second switching transistor Q2 is used to control the switching of current in the primary winding of the second transformer T2, thereby realizing the storage and release of energy.

[0074] The type of the second switch Q2 can be selected according to specific needs. As an example, the second switch Q2 is of the same type as the first switch Q1. The second control signal is generated by the control circuit. The control circuit adjusts the on and off times (duty cycle) of the second switch Q2 based on feedback signals such as the output voltage and current of the second rectifier output unit 210 to achieve stable control of the output second power supply voltage. In actual implementation, the control circuits generating the first and second control signals can be the same circuit or independent circuits; this embodiment does not limit this.

[0075] The second rectifier output unit 210 may include a second rectifier diode D3 and a second filter capacitor C2. The anode of the second rectifier diode D3 is connected to the first terminal of the secondary winding of the second transformer T2, and the cathode of the second rectifier diode D3 is connected to the first terminal of the second filter capacitor C2. The second terminal of the second filter capacitor C2 is connected to the second terminal of the secondary winding. The two ends of the second filter capacitor C2 are used to connect to a first load. This achieves effective rectification and filtering of the output voltage of the secondary winding of the second transformer T2 to provide a stable and reliable second power supply voltage.

[0076] In this embodiment, by employing a second conversion circuit 200 with a flyback converter topology, the effective conversion of the voltage provided by the first power supply voltage or the backup power supply is achieved, which can provide a stable secondary power supply for the first load.

[0077] It is understood that in other embodiments, the second conversion circuit 200 may also adopt other topologies, such as BUCK circuit, BOOST circuit, forward converter, push-pull circuit, etc., and those skilled in the art can set them according to the actual situation.

[0078] The number of secondary windings of the second transformer T2 and the number of second rectifier output units 210 can be flexibly set according to actual needs. In scenarios where there are multiple first loads, the number of secondary windings of the second transformer T2 and the number of second rectifier output units 210 can be multiple, for example, the same as the number of first loads. The secondary windings of the second transformer T2 are connected one-to-one with the first loads through the second rectifier output units 210.

[0079] Each secondary winding has a specific turns ratio to meet different voltage transformation requirements. For example, such as... Figure 4 As shown, the two primary loads in the electrical equipment, such as the driver chip and control chip of the frequency converter circuit, require power supply voltages of 15V and 5V respectively. Then, the two secondary windings of the second transformer T2 will be designed according to the corresponding turns ratio to output voltages suitable for the driver chip and the control chip respectively.

[0080] In this embodiment, by equipping each first load with an independent secondary winding and a second rectifier output unit 210, the second power supply voltage can be precisely adjusted according to the specific needs of each first load, thereby improving the working stability of each load.

[0081] In practical applications, the number of second conversion circuits 200 can also be flexibly set according to actual needs, such as... Figure 5 As shown, there are multiple second conversion circuits 200, for example, the number can be the same as the number of first loads. The input terminal of each second conversion circuit 200 is connected to the output terminal of the first conversion circuit 100, and the output terminal of each second conversion circuit 200 is used to connect to a corresponding first load.

[0082] In this embodiment, each second conversion circuit 200 has an independent topology, and the topologies of each second conversion circuit 200 may be the same or different. The input terminal of each second conversion circuit 200 is connected to the output terminal of the first conversion circuit 100, and is connected to the first power supply voltage or the backup power supply voltage to convert it into a power supply voltage suitable for each first load.

[0083] Taking an elevator as an example, which includes a frequency converter circuit's drive chip and control chip, the drive chip and control chip require 15V and 5V power supply voltages respectively. Then, the output of one of the second conversion circuits 200 is connected to the drive chip, and the output of the other second conversion circuit 200 is connected to the control chip. The two second conversion circuits 200 output voltages suitable for the drive chip and control chip respectively.

[0084] It is understandable that when the number of second conversion circuits 200 exceeds the number of first loads, the output terminals of the extra second conversion circuits 200 do not need to be connected, and these second conversion circuits 200 can stop outputting.

[0085] In this embodiment, each of the second conversion circuits 200 is independent of each other. When one of the second conversion circuits 200 or its corresponding first load fails, it will not affect the normal operation of other parts. Therefore, the reliability and stability of the electrical equipment can be improved, and fault diagnosis and maintenance are facilitated.

[0086] In some embodiments, such as Figure 6 As shown, the first load includes a control chip 400. The power supply terminal of the control chip is connected to the output terminal of one of the second conversion circuits 200, and the output terminal of the control chip is connected to the control terminals of the first conversion circuit 100 and the remaining second conversion circuits 200. The control chip is used to control the output state of the first conversion circuit 100 and the remaining second conversion circuits 200.

[0087] It is understandable that a second conversion circuit 200 connected to the power supply terminal of the control chip has an output power supply with voltage and current specifications suitable for the control chip, which can meet the normal needs of the control chip. For example, if the control chip requires a stable 5V DC power supply, and a certain second conversion circuit 200 outputs a 5V power supply, then it can be used as the power source for the control chip.

[0088] The output terminal of the control chip is connected to the control terminals of the first conversion circuit 100 and the other second conversion circuits 200, thereby enabling the sending of control signals to the first conversion circuit 100 and the second conversion circuits 200 to control their output states.

[0089] Specifically, the control chip can control the first conversion circuit 100 to output or stop outputting the first power supply voltage. The control chip can also adjust the magnitude of the first power supply voltage output by the first conversion circuit 100. For example, one pin of the control chip's output is connected to the gate of the first switching transistor Q1 of the first conversion circuit 100, and outputs a first control signal, which is a pulse width modulation (PWM) signal, to the first switching transistor Q1. By adjusting the duty cycle of the first control signal, the on and off times of the first switching transistor Q1 are controlled, thereby controlling the output state of the first conversion circuit 100.

[0090] The control chip can also control the second conversion circuit 200 to output or stop outputting the second power supply voltage, and can also adjust the voltage value of the second power supply voltage output by the second conversion circuit 200. For example, another pin of the control chip's output terminal is connected to the gate of the second switch Q2 of the second conversion circuit 200, and outputs a second control signal to the second switch Q2. By adjusting the duty cycle of the second control signal, the on and off times of the second switch Q2 can be controlled, thereby controlling the output state of the second conversion circuit 200.

[0091] When the electrical equipment is working normally, the control chip can adjust the first power supply voltage of the first conversion circuit 100 to the expected value, adjust the second power supply voltage of the second conversion circuit 200 to the expected value, and can also control the second conversion circuit 200 that does not need power to stop outputting.

[0092] When the device needs to be in standby mode, the control chip can output a corresponding control signal to stop the first conversion circuit 100 from outputting, allowing an external backup power supply to provide the power voltage so that the second conversion circuit 200, which powers the control chip, can continue to supply power. At this time, the control chip also controls the remaining second conversion circuits 200 to stop outputting, thus achieving low-power standby functionality. The control chip can also control the first conversion circuit 100 to reduce its output, allowing the second conversion circuit 200 to continue supplying power, while simultaneously controlling the remaining second conversion circuits 200 to stop outputting, thereby reducing the device's standby power consumption.

[0093] In actual implementation, the control chip can also be connected to the second conversion circuit 200 that powers it, and output corresponding control signals to control the output state of the second conversion circuit 200. The specific settings can be configured according to actual needs.

[0094] This application also provides an electrical device, including a backup power supply, a first load, and a power conversion circuit. The power conversion circuit can be configured as described in the above embodiments, and will not be repeated here.

[0095] In some embodiments, the electrical equipment further includes a second load, and the output terminals of the first conversion circuit and the unidirectional switch circuit in the power conversion circuit are both connected to the second load, so that the first load and the second load are powered simultaneously.

[0096] In some embodiments, the electrical equipment is an elevator, the first load includes a frequency conversion circuit and a drive control circuit, the drive control circuit is connected to the output terminal of the second conversion circuit 200 in the power conversion circuit, and the second power supply voltage output by the second conversion circuit 200 supplies power to the drive control circuit.

[0097] The drive control circuit is also connected to the frequency converter circuit. When the second power supply voltage is received, the drive control circuit is used to control the operating state of the frequency converter circuit or to perform star control on the frequency converter circuit.

[0098] like Figure 7 As shown, the elevator includes a frequency converter circuit 500, a drive control circuit 600, a motor 700, and a car (not shown). The frequency converter circuit 500 is electrically connected to both the drive control circuit 600 and the motor 700, and the motor 700 is mechanically connected to the car.

[0099] When the power supply is normal, the drive control circuit 600 operates based on the second power supply voltage output by the second conversion circuit 200, and adjusts the output parameters of the frequency converter circuit 500 according to actual needs, thereby controlling the speed and direction of the motor 700 and driving the car to accelerate, decelerate, and stop smoothly. When the power supply is abnormal, a backup power supply is quickly connected to the circuit, allowing the second conversion circuit 200 to continue outputting the second power supply voltage, and the drive control circuit 600 to continue operating. At this time, the drive control circuit 600 performs satellite control of the frequency converter circuit 500 to prevent accidents such as car collisions or falls, ensuring the safe operation of the car.

[0100] In some embodiments, such as Figure 8 As shown, the drive control circuit 600 includes a control chip 400 and a drive chip 610.

[0101] The driver chip 610 is connected to the control chip 400, and the driver chip 610 is also connected to the frequency converter circuit 500. The control chip 400 is used to output operating control signals to the driver chip 610, and the driver chip 610 outputs driving signals to the frequency converter circuit 500 according to the operating control signals, so as to control the operating status of the frequency converter circuit 500 or to perform satellite control on the frequency converter circuit 500.

[0102] As an example, the frequency converter circuit 500 includes a bus capacitor Cbus and an inverter circuit. The inverter circuit includes a first transistor Q3, a second transistor Q4, a third transistor Q5, a fourth transistor Q6, a fifth transistor Q7, and a sixth transistor Q8. The control electrode (such as the gate) of each transistor is connected to the driver chip 610. The driver chip 610 outputs corresponding drive signals to each transistor based on the operating control signal output by the control chip. Through the switching action of each transistor, the DC bus voltage is converted into a three-phase AC voltage, driving the motor M to run, thereby moving the car.

[0103] In this embodiment, at least two second conversion circuits are used. The input terminal of each second conversion circuit is connected to the output terminal of the first conversion circuit. The output terminal of one of the second conversion circuits is connected to the control chip to supply control power voltage to the control chip 400, and the output terminal of the other second conversion circuit is connected to the driver chip to supply drive power voltage to the driver chip 610. In the event of a power supply failure, the power switching diode D1 switches to the backup power supply, allowing the driver chip 610 and the control chip 400 to continue operating. By shorting the windings of the motor M through the fourth transistor Q6, the fifth transistor Q7, and the sixth transistor Q8, a star-sealing operation is achieved, ensuring the safe operation of the elevator.

[0104] Understandable. Figure 8 The diagram illustrates the connection between the transistors related to the star-sealing circuit and the driver chip 610. In practical applications, all transistors in the inverter circuit can be connected to the driver chip 610, or some transistors can be connected to the driver chip 610 and some transistors can be connected to other driver chips.

[0105] In some embodiments, such as Figure 9 As shown, there are multiple drive chips 610, each of which is connected to the control chip 400. Each drive chip 610 is used to connect one-to-one with the control electrode of the transistor in the frequency conversion circuit 500.

[0106] The control chip 400 outputs operating control signals to each drive chip 610. Each drive chip 610 outputs a corresponding drive signal to each transistor in the frequency converter circuit 500 based on the received operating control signal. The switching action of each transistor converts the DC bus voltage into a three-phase AC voltage, driving the motor M to run and thus moving the car. Alternatively, by shorting the windings of the motor M with the fourth transistor Q6, the fifth transistor Q7, and the sixth transistor Q8, a star-sealing operation is achieved to ensure the safety of elevator operation.

[0107] The control chip 400 and each driver chip 610 may require the same or different power supply voltages. Therefore, the number of second conversion circuits 200 can correspond to the total number of control chips 400 and driver chips 610. One of the second conversion circuits 200 has its output connected to the control chip 400, providing it with a control power supply voltage. The outputs of the remaining second conversion circuits 200 are connected one-to-one to each driver chip 610, providing a suitable drive power supply voltage for each driver chip 610.

[0108] Furthermore, the power supply terminal of the control chip 400 is connected to the output terminal of one of the second conversion circuits 200, and the output terminal of the control chip 400 is connected to the control terminals of the first conversion circuit 100 and the remaining second conversion circuits 200; the control chip 400 is used to control the output state of the first conversion circuit 100 and the remaining second conversion circuits 200.

[0109] When the elevator needs to be in standby mode, the control chip 400 can output a corresponding control signal to stop the first conversion circuit 100 from outputting, and the power supply voltage is provided by an external backup power supply so that the second conversion circuit 200, which powers the control chip 400, can continue to be powered. At this time, the control chip 400 controls the remaining second conversion circuits 200 to stop outputting, thereby realizing the low-power standby function.

[0110] In some embodiments, when the drive control circuit 600 includes a control chip 400 and a drive chip 610, the control chip 400 is connected to the drive chip 610; when such a configuration is used... Figure 4 When the flyback topology shown is used as the topology of the second conversion circuit 200, the secondary winding of the second transformer T2 and the number of second rectifier output units 210 can be multiple. Each secondary winding is connected to a corresponding second rectifier output unit 210 to form multiple output circuits. The output terminal of one of the output circuits is connected to the control chip 400 to provide a suitable control power supply voltage for the control chip 400, and the output terminal of another output circuit is connected to the driver chip to provide a suitable drive power supply voltage for the driver chip 610. In the event of an abnormal power supply, the power switching diode D1 switches to the backup power supply, allowing the driver chip 610 and the control chip 400 to continue operating. By shorting the winding of the motor M through the fourth transistor Q6, the fifth transistor Q7, and the sixth transistor Q8, a star-sealing operation is achieved, ensuring the safe operation of the elevator.

[0111] Understandable. Figure 8 The diagram illustrates the connection between the transistors related to the star-sealing circuit and the driver chip 610. In practical applications, all transistors in the inverter circuit can be connected to the driver chip 610, or some transistors can be connected to the driver chip 610 and some transistors can be connected to other driver chips.

[0112] In some embodiments, such as Figure 9 As shown, the number of driver chips 610 is set to multiple, and each driver chip 610 is connected to the control chip 400. When a driver chip 610 is selected, the following applies: Figure 4 When the flyback topology shown is used as the topology of the second conversion circuit 200, the number of secondary windings of the second transformer T2 and the number of second rectifier output units 210 can be multiple. Each secondary winding is connected to a corresponding second rectifier output unit 210 to form multiple output circuits. The output terminal of one of the output circuits is connected to the control chip 400 to provide a suitable control power supply voltage for the control chip 400, and the output terminals of the other output circuits are connected one-to-one with each driver chip 610 to provide a suitable drive power supply voltage for each driver chip 610.

[0113] In this embodiment, a two-stage power supply architecture is constructed using the first conversion circuit 100 and the second conversion circuit 200. The first-stage power supply draws power from the bus to generate the first-stage output (first power supply voltage). The first power supply voltage is typically 26V, which can power the elevator fan, soft-start relay, and other second-stage loads, as well as the second-stage power supply. The backup power supply is connected to the output of the first-stage power supply via a power switching diode D1. The backup power supply is typically 24V, lower than the output of the first-stage power supply, ensuring bus power supply during normal operation. When the mains power fails, causing the output to drop below 24V, the external backup power supply automatically switches in, enabling rapid switching and powering the downstream control chip 400 and driver chip 610, etc., to achieve satellite shutdown and emergency response.

[0114] In the description of this specification, references to terms such as "some embodiments," "other embodiments," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative descriptions of the above terms do not necessarily refer to the same embodiments or examples.

[0115] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0116] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this application. 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 modifications and improvements all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A power conversion circuit, characterized in that, include: A first conversion circuit, wherein the input terminal of the first conversion circuit is used to connect to a power supply, and the first conversion circuit is used to convert the voltage provided by the power supply into a first power supply voltage; A one-way switch circuit is provided, wherein the input terminal of the one-way switch circuit is used to connect to a backup power supply, and the output terminal of the one-way switch circuit is connected to the output terminal of the first conversion circuit. The one-way switch circuit is turned on when the voltage at the output terminal of the first conversion circuit is lower than a preset voltage threshold, and is turned off when the voltage at the output terminal of the first conversion circuit is greater than or equal to the preset voltage threshold. The second conversion circuit has its input terminals connected to the output terminals of the first conversion circuit and the unidirectional switch circuit, respectively. The output terminal of the second conversion circuit is used to connect to the first load. The second conversion circuit is used to convert the first power supply voltage or the voltage provided by the backup power supply into a second power supply voltage that matches the first load.

2. The power conversion circuit according to claim 1, characterized in that, The unidirectional switching circuit includes a power switching diode; the anode of the power switching diode serves as the input terminal of the unidirectional switching circuit, and the cathode of the power switching diode serves as the output terminal of the unidirectional switching circuit; the preset voltage threshold is determined based on the parameters of the backup power supply and the power switching diode.

3. The power conversion circuit according to claim 1, characterized in that, The first conversion circuit includes: The first transformer, wherein the first end of the primary winding of the first transformer is used to connect to the power supply; The first switching transistor has its first terminal connected to the second end of the primary winding of the first transformer, its second terminal connected to the power supply, and its control terminal used to receive a first control signal. The first rectifier output unit is connected to the secondary winding of the first transformer, the input terminal of the second conversion circuit, and the output terminal of the unidirectional switch circuit. The first rectifier output unit is used to output the first power supply voltage.

4. The power conversion circuit according to claim 1, characterized in that, The second conversion circuit includes: The second transformer has its primary winding connected at the first end to the output of the first conversion circuit and the output of the unidirectional switching circuit. The second switching transistor has its first terminal connected to the second end of the primary winding of the second transformer, its second terminal connected to the output terminal of the first conversion circuit, and its control terminal used to receive a second control signal. The second rectifier output unit is connected to the secondary winding of the second transformer and the first load, and is used to output the second power supply voltage to the first load.

5. The power conversion circuit according to claim 4, characterized in that, The number of the secondary windings of the second transformer and the number of the second rectifier output units are both multiple. Each secondary winding of the second transformer is connected to a corresponding second rectifier output unit, and the second rectifier output unit is also used to be connected to a corresponding first load.

6. The power conversion circuit according to claim 1, characterized in that, There are multiple second conversion circuits, and the input terminal of each second conversion circuit is connected to the output terminal of the first conversion circuit. The output terminal of each second conversion circuit is used to connect to a corresponding first load.

7. The power conversion circuit according to claim 6, characterized in that, The first load includes a control chip, the power supply terminal of which is connected to the output terminal of one of the second conversion circuits, and the output terminal of which is connected to the control terminals of the first conversion circuit and the remaining second conversion circuits. The control chip is used to control the output state of the first conversion circuit and the remaining second conversion circuits.

8. The power conversion circuit according to any one of claims 1-7, characterized in that, The output terminals of the first conversion circuit and the unidirectional switch circuit are also used to connect a second load, the second load having a different voltage level than the first load.

9. An electrical appliance, characterized in that, It includes a backup power supply, a first load, and a power conversion circuit as described in any one of claims 1-8.

10. The electrical equipment according to claim 9, characterized in that, The electrical equipment is an elevator, and the first load includes a frequency converter circuit and a drive control circuit; the drive control circuit is connected to the output terminal of the second conversion circuit in the power conversion circuit, and the second power supply voltage output by the second conversion circuit supplies power to the drive control circuit. The drive control circuit is also connected to the frequency converter circuit, and is used to control the operating state of the frequency converter circuit or to perform star-controlled operation on the frequency converter circuit.

11. The electrical equipment according to claim 10, characterized in that, The drive control circuit includes a drive chip and a control chip, and the control chip is connected to the drive chip. There are multiple second conversion circuits, and the input terminal of each second conversion circuit is connected to the output terminal of the first conversion circuit. The output terminal of one second conversion circuit is connected to the control chip, and the output terminal of another second conversion circuit is connected to the driver chip.

12. The electrical equipment according to claim 11, characterized in that, The number of the driving chips is set to multiple, and the control chip is connected to each of the driving chips; One of the output terminals of the second conversion circuit is connected to the control chip, and the output terminals of the remaining second conversion circuits are connected one-to-one with the respective driver chips.

13. The electrical equipment according to claim 10, characterized in that, The drive control circuit includes a drive chip and a control chip, and the control chip is connected to the drive chip. The second conversion circuit includes a second transformer and a second rectifier output unit. The second transformer has multiple secondary windings and multiple second rectifier output units. Each secondary winding is connected to a second rectifier output unit to form multiple output circuits. The output terminal of one of the output circuits is connected to the control chip, and the output terminal of another output circuit is connected to the driver chip.

14. The electrical equipment according to claim 13, characterized in that, The driving chip is configured as a plurality of the driving chips, and the control chip is connected to each of the driving chips; One of the output circuits is connected to the control chip, and the outputs of the other output circuits are connected one-to-one with the respective driver chips.

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