Circuit unit and power conversion device comprising same
By using a zero-current switching technology with a single-pole double-throw relay and a series-connected switching resistor in the power conversion device, the problems of large relay size and interference during input redundancy switching in the prior art are solved, and a highly reliable and low-cost power conversion device is realized.
Patent Information
- Application Number
- CN202423207109.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-25
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2034-12-25
AI Technical Summary
Existing power conversion devices cannot achieve zero-current switching when implementing input redundancy, resulting in large relay size, high cost, and internal power supply interference, which affects reliability.
A single-pole double-throw relay and a series-connected switching resistor are used in conjunction with a control circuit to achieve zero-current switching. Switching between normally closed and normally open contacts is achieved through a control signal, avoiding relay arcing. A second switching unit is used to bypass the relay to simplify the control process.
It achieves zero-current switching, protects relays, extends service life, reduces the size and cost of power conversion devices, improves reliability, and reduces internal power supply interference.
Smart Images
Figure CN223613221U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of power supply, especially a circuit unit and a power conversion device comprising the same. BACKGROUND
[0002] With the development of power supply technology, higher requirements are put forward for power conversion devices.
[0003] For example, the reliability of internal electronic components of the power conversion device and the stability of power supply both affect the reliability of the power conversion device.
[0004] High reliability is one of the important indicators of the power conversion device, so how to design a high-reliability power conversion device has become the focus of the industry. SUMMARY
[0005] The present application provides a circuit unit, comprising: a single-pole double-throw relay, including a common terminal, a normally closed contact and a normally open contact; a switch resistance series branch, including a first switch unit and a resistance unit connected in series, the first end of the switch resistance series branch is connected to the normally closed contact, and the second end of the switch resistance series branch is connected to the normally open contact, wherein the common terminal of the single-pole double-throw relay is used to connect a power supply circuit, the second end of the switch resistance series branch is used to connect a power conversion circuit, and the output end of the power conversion circuit includes a bus capacitor.
[0006] Further, it further comprises: a second switch unit connected between the common terminal of the single-pole double-throw relay and the second end of the switch resistance series branch.
[0007] Further, the power supply circuit is a power source.
[0008] Further, the power supply circuit comprises: a relay switching unit comprising at least one relay, having a first input end, a second input end and an output end, the first input end is used to connect a first power source, the second input end is used to connect a second power source, and the output end is connected to the common terminal of the single-pole double-throw relay.
[0009] Further, the first switch unit is a thyristor, a MOS tube or a relay.
[0010] Further, the second switch unit is a thyristor, a MOS tube or a relay.
[0011] The application further provides a power conversion device, comprising: a relay switching unit comprising at least one relay, having a first input end, a second input end and an output end, the first input end being used for connecting a first power source, the second input end being used for connecting a second power source; a single-pole double-throw relay comprising a common end, a normally closed contact and a normally open contact, the output end of the relay switching unit being connected to the common end of the single-pole double-throw relay; a switch-resistor series branch comprising a first switch unit and a resistor unit connected in series, the first end of the switch-resistor series branch being connected to the normally closed contact, the second end of the switch-resistor series branch being connected to the normally open contact; a second switch unit connected between the common end of the single-pole double-throw relay and the second end of the switch-resistor series branch; a power conversion circuit, the input end of which being connected to the second end of the switch-resistor series branch, wherein the output end of the power conversion circuit comprises a bus capacitor; and a control circuit used for outputting control signals for controlling the single-pole double-throw relay, the first switch unit and the second switch unit.
[0012] Further, at the time of starting, the control circuit is configured to output control signals so that the first switch unit is turned on, the second switch unit is turned off, and the common end of the single-pole double-throw relay is connected to the normally closed contact of the single-pole double-throw relay; when the voltage of the bus capacitor is charged to a predetermined value, the control circuit is configured to output control signals so that the first switch unit and the second switch unit are turned off, and the common end of the single-pole double-throw relay is connected to the normally open contact of the single-pole double-throw relay.
[0013] Further, during the operation of the power conversion device, and when it is required to switch between the first power source and the second power source, the control circuit is configured to output control signals so that the second switch unit is turned on, and the first switch unit is turned off; at the same time or afterwards, the common end of the single-pole double-throw relay is switched from being connected to the normally open contact to being connected to the normally closed contact; then the second switch unit is turned off; at the same time or afterwards, the switching between the first power source and the second power source is performed; then the second switch unit is turned on; at the same time or afterwards, the common end of the single-pole double-throw relay is switched from being connected to the normally closed contact to being connected to the normally open contact; then the second switch unit is turned off.
[0014] The application also provides a power conversion device, comprising: a relay switching unit comprising at least one relay, having a first input end, a second input end and an output end, the first input end being used for connecting a first power source, the second input end being used for connecting a second power source; a single-pole double-throw relay comprising a common end, a normally closed contact and a normally open contact, the output end of the relay switching unit being connected to the common end of the single-pole double-throw relay; a switch-resistor series branch comprising a first switch unit and a resistor unit connected in series, the first end of the switch-resistor series branch being connected to the normally closed contact, the second end of the switch-resistor series branch being connected to the normally open contact; a power conversion circuit, the input end of which being connected to the second end of the switch-resistor series branch, wherein the output end of the power conversion circuit comprises a bus capacitor; and a control circuit, used for outputting control signals for controlling the single-pole double-throw relay, the first switch unit and the power conversion circuit.
[0015] Further, when starting, the control circuit is configured to output control signals such that the first switch unit is turned on and the common end of the single-pole double-throw relay is connected to the normally closed contact of the single-pole double-throw relay; when the voltage of the bus capacitor is charged to a predetermined value, the control circuit is configured to output control signals such that the first switch unit is turned off and the common end of the single-pole double-throw relay is connected to the normally open contact of the single-pole double-throw relay.
[0016] Further, during the operation of the power conversion device, when it is required to switch between the first power source and the second power source, the control circuit is configured to output control signals such that the first switch unit is turned off and the power conversion circuit is not operated; at the same time or subsequently, the common end of the single-pole double-throw relay is switched from being connected to the normally open contact to being connected to the normally closed contact; at the same time or subsequently, the switching between the first power source and the second power source is performed; at the same time or subsequently, the common end of the single-pole double-throw relay is switched from being connected to the normally closed contact to being connected to the normally open contact; and then the power conversion circuit is operated. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 The circuit unit of an embodiment of the application.
[0018] Figure 2 The circuit unit of another embodiment of the application.
[0019] Figure 3 The power conversion device comprising the circuit unit of Figure 1 of an embodiment of the application.
[0020] Figure 4 The power conversion device comprising the circuit unit of another embodiment of the application.Figure 2 Power conversion device schematic diagram of circuit unit in
[0021] Figure 5 Power conversion device schematic diagram of circuit unit in Figure 3 Power conversion device start-up control waveform schematic diagram in
[0022] Figure 6 Power conversion device schematic diagram of circuit unit in Figure 3 Power conversion device power supply end switching control waveform schematic diagram in
[0023] Figure 7 Power conversion device schematic diagram of circuit unit in Figure 4 Power conversion device start-up control waveform schematic diagram in
[0024] Figure 8 Power conversion device schematic diagram of circuit unit in Figure 4 Power conversion device power supply end switching control waveform schematic diagram in DETAILED DESCRIPTION
[0025] The technical solutions in the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.
[0026] In an embodiment of the present application, a circuit unit is provided. As shown in the circuit unit schematic diagram of the embodiment of the present application in Figure 1 The circuit unit comprises:
[0027] A single-pole double-throw relay Rc comprises a common terminal 1, a normally closed contact 2 and a normally open contact 3.
[0028] A switch resistor series branch 120 comprises a first switch unit S1 and a resistor unit R connected in series. The first end of the switch resistor series branch 120 is connected to the normally closed contact 2, and the second end of the switch resistor series branch 120 is connected to the normally open contact 3.
[0029] The common terminal 1 of the single-pole double-throw relay Rc is used to connect a power supply circuit 210, the second end of the switch resistor series branch 120 is used to connect a power conversion circuit 300, and the output end of the power conversion circuit 300 comprises a bus capacitor Co.
[0030] Further, the circuit unit can further comprise a power supply circuit 210, a power conversion circuit 300 and a load circuit 400. Figure 2The circuit unit schematic diagram of another embodiment of the present application is shown, and the circuit unit further comprises a second switch unit S2 connected between the common terminal 1 of the single-pole double-throw relay Rc and the second terminal of the switch resistance series branch 120.
[0031] As shown in Figure 1 and Figure 2 , the first switch unit S1 is implemented as a bidirectional thyristor, but the present application is not limited thereto, and any switch tube capable of switching between conduction and non-conduction through control is applicable to the present application, such as a thyristor, a MOS tube or a relay, etc. The second switch unit S2 is similar to the first switch unit S1, and will not be described herein again.
[0032] As shown in Figure 1 and Figure 2 , the resistance unit R is implemented as a resistance, but the present application is not limited thereto, and it can also be a thermistor, or it can be a plurality of resistances in series or parallel, as long as it presents a resistance.
[0033] In actual implementation, the power supply circuit 210 can be implemented as a power source, such as a voltage source. It can be an alternating current or a direct current.
[0034] In actual implementation, the power supply circuit 210 can also be implemented as a double-input power supply. Specifically, it can participate in Figure 3 The power supply conversion device schematic diagram of an embodiment of the present application comprising the circuit unit in Figure 1 , and Figure 4 The power supply conversion device schematic diagram of another embodiment of the present application comprising the circuit unit in Figure 2 . As shown in Figure 3 and Figure 4 , the power supply circuit 210 comprises a relay switching unit 210 comprising at least one relay, having a first input terminal, a second input terminal and an output terminal, the first input terminal being used for connecting a first power source V1, the second input terminal being used for connecting a second power source V2, and the output terminal being connected to the common terminal 1 of the single-pole double-throw relay Rc.
[0035] More specifically, please refer to Figure 3 The power supply conversion device comprises:
[0036] a relay switching unit 210 comprising at least one relay, having a first input terminal, a second input terminal and an output terminal, the first input terminal being used for connecting a first power source V1, the second input terminal being used for connecting a second power source V2;
[0037] a single-pole double-throw relay Rc comprising a common terminal 1, a normally closed contact 2 and a normally open contact 3, the output terminal of the relay switching unit 210 being connected to the common terminal 1 of the single-pole double-throw relay Rc;
[0038] The series switch resistor branch 120 includes a first switch unit S1 and a resistor unit R connected in series. The first end of the series switch resistor branch 120 is connected to a normally closed contact 2, and the second end of the series switch resistor branch 120 is connected to a normally open contact 3.
[0039] The power conversion circuit 300 has its input terminal connected to the second terminal of the series branch 120 of the switching resistor, and its output terminal includes a bus capacitor Co.
[0040] The control circuit 400 is used to output control signals for controlling the single-pole double-throw relay Rc, the first switching unit S1, and the power conversion circuit 300.
[0041] See also Figure 5 shown Figure 3 The diagram shows the control waveforms of the power conversion device during startup, where DRV Rc is the control signal controlling the single-pole double-throw relay Rc, and DRV S1 is the control signal controlling the first switching unit S1. Figure 5 As shown, when the power conversion device is turned on, that is, when the power supply circuit 210 starts to provide the input voltage Vin to the power conversion circuit 300, the control circuit 400 is configured to output a control signal that causes the first switching unit S1 to be turned on and the common terminal 1 of the single-pole double-throw relay Rc to be connected to the normally closed contact 2 of the single-pole double-throw relay Rc; when the voltage of the bus capacitor Co is charged to a predetermined value, the control circuit 400 is configured to output a control signal that causes the first switching unit S1 to be turned off and the common terminal 1 of the single-pole double-throw relay Rc to be connected to the normally open contact 3 of the single-pole double-throw relay Rc.
[0042] As can be seen, when the computer is powered on, if... Figure 5 At time T1, by controlling the single-pole double-throw relay Rc and the first switching unit S1, the start-up current flows through the common terminal 1 and normally closed contact 2 of the single-pole double-throw relay Rc, and the series branch 120 of the switching resistor. The resistor unit R then suppresses the start-up surge current and charges the bus capacitor Co of the power conversion circuit 300. When the voltage of the bus capacitor Co is charged to a predetermined value, such as... Figure 5 At time T2, the first switching unit S1 is turned off, and the common terminal 1 of the single-pole double-throw relay Rc is connected to the normally open contact 3 of the single-pole double-throw relay Rc. Then, the current flows through the common terminal 1 and the normally open contact 3 of the single-pole double-throw relay Rc to supply power to the subsequent power conversion circuit 300.
[0043] In actual implementation, the predetermined value of the bus capacitor Co can be set according to different converters, and this application does not limit it.
[0044] like Figure 5 As shown, when the control signal DRV S1 given to the first switching unit S1 is high, it is turned on; when it is low, it is turned off.Figure 5 As shown, when the control signal DRV Rc of the single-pole double-throw relay Rc is high, the common terminal 1 of the single-pole double-throw relay Rc is connected to the normally open contact 3; and when the control signal DRV Rc of the single-pole double-throw relay Rc is low, the common terminal 1 of the single-pole double-throw relay Rc is connected to the normally closed contact 2.
[0045] The surge current suppression method of the start-up process is also applicable to the embodiment in which the power supply circuit 210 is implemented as a power source, and the principle is the same, which will not be described here.
[0046] In actual applications, in the case of continuous operation and non-power-off, in order to prevent the device from being shut down due to abnormal power supply (such as unstable power supply, power-off, etc.), many occasions will set up two different power supply systems as backup, for example: mains power supply and generator power supply, mains power supply and battery power supply, mains power supply and UPS power supply, etc., that is, as shown in the double-output power conversion device, the input redundancy function is realized. In the above power consumption scenarios, an automatic transfer switch (Automatic Transfer Switch, hereinafter referred to as ATS) is often used to realize the fast load switching of the two power supplies, to ensure the stable and reliable long-term operation of the power supply and the power consumption device, and to avoid downtime caused by input abnormalities and economic losses. Figure 3 And Figure 4 As shown in the double-output power conversion device, the input redundancy function is realized. In the above power consumption scenarios, an automatic transfer switch (Automatic Transfer Switch, hereinafter referred to as ATS) is often used to realize the fast load switching of the two power supplies, to ensure the stable and reliable long-term operation of the power supply and the power consumption device, and to avoid downtime caused by input abnormalities and economic losses.
[0047] However, the current industry has many drawbacks in various schemes for realizing input redundancy on the same power supply. For example, zero-current switching cannot be achieved, which requires consideration of arc extinction, the use of relays with arc-extinguishing devices, resulting in large relay size, and significant internal interference to the power supply during load switching, greatly increasing the size and cost of the power supply.
[0048] For the power conversion device shown in the present application Figure 3 As shown, during the operation of the power conversion device, if the power supply of one power supply end needs to be switched to the power supply of another power supply end due to failure, the power conversion device of the present application can realize zero-current switching. For details, refer to the control waveform diagram of the power conversion device of an embodiment of the present application Figure 6 Figure 3 in the power conversion device during power supply end switching, wherein DRV Rc is the control signal for controlling the single-pole double-throw relay Rc, DRV S1 is the control signal for controlling the first switching unit S1, and DRV P is the control signal for controlling the power conversion circuit 300.
[0049] As shown in Figure 6 During the operation of the power conversion device, and when switching between the first power source V1 and the second power source V2 is required, the control circuit 400 is configured to output the control signal:
[0050] so that the first switching unit S1 is turned off, and the power conversion circuit 300 does not work;
[0051] At the same time or subsequently, the common terminal 1 of the single-pole double-throw relay Rc is switched from the normally open contact 3 connected to the single-pole double-throw relay Rc to the normally closed contact 2;
[0052] Simultaneously or subsequently, switching is performed between the first power source V1 and the second power source V2;
[0053] At the same time or subsequently, the common terminal 1 of the single-pole double-throw relay Rc is switched from the normally closed contact 2 connected to the single-pole double-throw relay Rc to the normally open contact 3;
[0054] This then enables the power conversion circuit 300 to operate.
[0055] like Figure 6 As shown, during the operation of the power conversion device, if it is detected that the first power source V1 cannot supply power normally, but the second power source V2 can still supply power normally, then it is necessary to switch from the first power source V1 to the second power source V2 to extract the input voltage Vin.
[0056] like Figure 6 As shown, at time T1, if the first power source V1 is detected to be de-energized, the control signal to the power conversion circuit 300 is switched to a low level, causing the power conversion circuit 300 to stop working and the first switching unit S1 to be in the off state. Since the power conversion circuit 300 is not working and the first switching unit S1 is in the off state, the current flowing through the single-pole double-throw relay Rc is zero. Therefore, if at this time or later, such as Figure 6 As shown, at time T2, the control signal for the single-pole double-throw relay Rc is switched to a low level, causing the common terminal 1 of the single-pole double-throw relay Rc to switch from the normally open contact 3 to the normally closed contact 2. This enables zero-current switching of the single-pole double-throw relay Rc, avoiding arcing during relay switching, protecting the relay, extending its service life, and eliminating the need for an arc-extinguishing device.
[0057] Simultaneously or subsequently, switching occurs between the first power source V1 and the second power source V2, such as... Figure 6 As shown, the switching between the first power source V1 and the second power source V2 is completed between time T2 and time T3. Specifically, as follows... Figure 3 As shown, the control circuit 400 also outputs a control signal to control the relay switching unit 210, which can then control the relays within the relay switching unit 210 to switch from the first power source V1 to the second power source V2. For example... Figure 6As shown, at T3, the input voltage Vin is provided by the second power source V2, that is, the switching between the first power source V1 and the second power source V2 is completed. During this period, the first switch unit S1 is off, and the power conversion circuit 300 is not working, so that the zero current switching between the first power source V1 and the second power source V2 is realized, the inrush current during the switching between the two inputs is reduced, and the reliability of the power conversion device is improved.
[0058] Then or simultaneously, the common terminal 1 of the single-pole double-throw relay Rc is switched from the normally closed contact 2 to the normally open contact 3. As shown, Figure 6 As shown, at T3, the common terminal 1 of the single-pole double-throw relay Rc is switched from the normally closed contact 2 to the normally open contact 3. As analyzed above, the zero current switching of the single-pole double-throw relay Rc is also realized.
[0059] Then, the power conversion circuit 300 is enabled. As shown, Figure 6 As shown, at T4, the power conversion circuit 300 is enabled to ensure the zero current switching of the single-pole double-throw relay Rc at T3.
[0060] As can be seen from the above description, Figure 3 The power conversion device shown not only realizes the start-up surge suppression, but also realizes the zero current switching during the switching between the multiple inputs, thereby improving the reliability of the power conversion device and reducing the volume thereof.
[0061] For more details, please refer to Figure 4 The power conversion device shown comprises:
[0062] The relay switching unit 210 comprises at least one relay, has a first input terminal, a second input terminal and an output terminal, the first input terminal is used to connect the first power source V1, and the second input terminal is used to connect the second power source V2;
[0063] The single-pole double-throw relay Rc comprises a common terminal 1, a normally closed contact 2 and a normally open contact 3, and the output terminal of the relay switching unit 210 is connected to the common terminal 1 of the single-pole double-throw relay Rc;
[0064] The switch resistance series branch 120 comprises a first switch unit S1 and a resistance unit R connected in series, the first end of the switch resistance series branch 120 is connected to the normally closed contact 2, and the second end of the switch resistance series branch 120 is connected to the normally open contact 3;
[0065] The second switch unit S2 is connected between the common terminal 1 of the single-pole double-throw relay Rc and the second end of the switch resistance series branch 120;
[0066] The power conversion circuit 300 has its input terminal connected to the second terminal of the series branch 120 of the switching resistor, and its output terminal includes a bus capacitor Co.
[0067] The control circuit 400 is used to output control signals for controlling the single-pole double-throw relay Rc, the first switching unit S1, and the second switching unit S2.
[0068] See also Figure 7 shown Figure 4 A schematic diagram of the control waveforms when the power conversion device in the circuit is turned on. (Example:) Figure 7 As shown, DRV Rc is the control signal controlling the single-pole double-throw relay Rc, DRV S1 is the control signal controlling the first switching unit S1, and DRV S2 is the control signal controlling the second switching unit S2. Figure 7 As shown, when the power conversion device is powered on, the control circuit 400 is configured to output a control signal that causes the first switch unit S1 to be turned on, the second switch unit S2 to be turned off, and the common terminal 1 of the single-pole double-throw relay Rc to be connected to the normally closed contact 2 of the single-pole double-throw relay Rc; when the voltage of the bus capacitor Co is charged to a predetermined value, the control circuit 400 is configured to output a control signal that causes the first switch unit S1 and the second switch unit S2 to be turned off, and the common terminal 1 of the single-pole double-throw relay Rc to be connected to the normally open contact 3 of the single-pole double-throw relay Rc.
[0069] and Figure 3 and Figure 5 It is similar, except that the second switching unit S2 is put in the off state. Since the principle is the same, it will not be described in detail here.
[0070] The surge current method for this startup process is also applicable to embodiments where the power supply circuit 210 is implemented as a power source, and the principle is the same, so it will not be described again here.
[0071] Similarly, for Figure 4 The power conversion device shown can achieve zero-current switching if a power supply failure occurs at one power supply terminal and switching to another power supply terminal is required during operation. For details, please refer to [link to relevant documentation]. Figure 8 An embodiment of this application is shown. Figure 4 Control waveform diagram of the power supply switching device during power conversion.
[0072] like Figure 8 As shown, during the operation of the power conversion device, and when switching between the first power source V1 and the second power source V2 is required, the control circuit 400 is configured to output the following control signal:
[0073] This causes the second switching unit S2 to be turned on and the first switching unit S1 to be turned off.
[0074] At the same time or subsequently, the common terminal 1 of the single-pole double-throw relay Rc is switched from the normally open contact 3 connected to the single-pole double-throw relay Rc to the normally closed contact 2;
[0075] Then the second switching unit S2 is turned off;
[0076] Simultaneously or subsequently, switching is performed between the first power source V1 and the second power source V2;
[0077] Then the second switching unit S2 is turned on;
[0078] At the same time or subsequently, the common terminal 1 of the single-pole double-throw relay Rc is switched from the normally closed contact 2 connected to the single-pole double-throw relay Rc to the normally open contact 3;
[0079] Then the second switching unit S2 is turned off.
[0080] like Figure 8 As shown, at time T1, a power outage of the first power source V1 is detected, causing the first switching unit S1 to be in the off state and the second switching unit S2 to be switched on. The second switching unit S2 then bypasses the single-pole double-throw relay Rc and the series resistor branch 120, resulting in zero current flowing through the single-pole double-throw relay Rc. Therefore, if at this time or later, such as... Figure 8 As shown, at time T2, the control signal for the single-pole double-throw relay Rc is switched to a low level, causing the common terminal 1 of the single-pole double-throw relay Rc to switch from the normally open contact 3 to the normally closed contact 2. This enables zero-current switching of the single-pole double-throw relay Rc, avoiding arcing during relay switching, protecting the relay, extending its service life, and eliminating the need for an arc-extinguishing device.
[0081] Then as Figure 8 As shown, at time T3, the second switching unit S2 is turned off, which disconnects the relay switching unit 210 from the subsequent power circuit. This simultaneously or subsequently causes a switch between the first power source V1 and the second power source V2, as... Figure 8 As shown, the switching between the first power source V1 and the second power source V2 is completed between time T3 and time T4. Figure 8 As shown, starting at time T4, the second power source V2 provides the input voltage Vin, thus completing the switching between the first power source V1 and the second power source V2. Furthermore, as mentioned above, during this period, the relay switching unit 210 is disconnected from the subsequent power circuit, enabling zero-current switching between the first power source V1 and the second power source V2. This reduces the inrush current during the switching of the two input paths and improves the reliability of the power conversion device.
[0082] Then the second switching unit S2 is turned on, such as Figure 8As shown in T4, the second switch unit S2 is turned on, and the second switch unit S2 bypasses the single-pole double-throw relay Rc and the switch resistor series branch 120 again, so that the current flowing through the single-pole double-throw relay Rc is zero,
[0083] At the same time or later, the common terminal 1 of the single-pole double-throw relay Rc is switched from the normally closed contact 2 to the normally open contact 3 by connecting the normally closed contact 2 of the single-pole double-throw relay Rc. As Figure 8 As shown, that is, at T4, the common terminal 1 of the single-pole double-throw relay Rc is switched from the normally closed contact 2 to the normally open contact 3 by connecting the normally closed contact 2 of the single-pole double-throw relay Rc. As analyzed above, zero current switching of the single-pole double-throw relay Rc is achieved.
[0084] Then the second switch unit S2 is turned off. As Figure 8 As shown, at T5, the second switch unit S2 is turned off, and the common terminal 1 of the single-pole double-throw relay Rc is connected to the normally open contact 3 to supply power to the power conversion circuit 300.
[0085] As described above, the power conversion device in Figure 3 , Figure 4 The power conversion device in Figure 3 The power conversion device in Figure 4 The power conversion device shown in
[0086] As described above, Figure 1 and Figure 2 The power supply unit and the power conversion device using the same in
[0087] In actual implementation, the power sources input to the first power supply terminal V1 and the second power supply terminal V2 can be alternating voltages or direct currents, which are not limited in the present application
[0088] In actual implementation, the first power supply terminal V1 can be selected as the main input, or the second power supply terminal V2 can be selected as the main input.
[0089] In actual implementation, the power conversion device can further include a plurality of filter circuits to improve the EMI performance of the power conversion device.
[0090] In actual implementation, the power conversion circuit 300 can be a boost circuit, but the present application does not limit the power conversion circuit 300, which can be modified according to different application requirements.
[0091] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not limited to them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A circuit unit, characterized in that, The application relates to a power supply circuit, comprising: a single-pole double-throw relay comprising a common terminal, a normally closed contact and a normally open contact; a switch-resistor series branch comprising a first switch unit and a resistor unit connected in series, a first end of the switch-resistor series branch being connected to the normally closed contact, and a second end of the switch-resistor series branch being connected to the normally open contact, wherein the common terminal of the single-pole double-throw relay is used for connecting a power supply circuit, the second end of the switch-resistor series branch is used for connecting a power conversion circuit, and an output end of the power conversion circuit comprises a bus capacitor.
2. The circuit unit according to claim 1, characterized in that, Further comprising: a second switch unit connected between the common terminal of the single-pole double-throw relay and the second end of the switch-resistor series branch.
3. The circuit unit according to claim 1 or 2, characterized in that, The power supply circuit is a power source.
4. The circuit unit according to claim 1 or 2, characterized by The power supply circuit comprises: a relay switching unit comprising at least one relay, having a first input end, a second input end and an output end, the first input end being used for connecting a first power source, the second input end being used for connecting a second power source, and the output end being connected to the common terminal of the single-pole double-throw relay.
5. The circuit unit according to claim 1, characterized by The first switch unit is a thyristor, a MOS tube or a relay.
6. The circuit unit according to claim 2, characterized by The second switch unit is a thyristor, a MOS tube or a relay.
7. A power conversion device, characterized by comprising: The application relates to a power supply circuit, comprising: a relay switching unit comprising at least one relay, having a first input end, a second input end and an output end, the first input end being used for connecting a first power source, the second input end being used for connecting a second power source; a single-pole double-throw relay comprising a common terminal, a normally closed contact and a normally open contact, the output end of the relay switching unit being connected to the common terminal of the single-pole double-throw relay; a switch-resistor series branch comprising a first switch unit and a resistor unit connected in series, a first end of the switch-resistor series branch being connected to the normally closed contact, and a second end of the switch-resistor series branch being connected to the normally open contact; a second switch unit connected between the common terminal of the single-pole double-throw relay and the second end of the switch-resistor series branch; a power conversion circuit, an input end of the power conversion circuit being connected to the second end of the switch-resistor series branch, wherein an output end of the power conversion circuit comprises a bus capacitor; a control circuit used for outputting control signals for controlling the single-pole double-throw relay, the first switch unit and the second switch unit.
8. The power conversion device of claim 7, wherein, When starting, the control circuit is configured to output the control signals so that the first switch unit is turned on, the second switch unit is turned off, and the common terminal of the single-pole double-throw relay is connected to the normally closed contact of the single-pole double-throw relay. When the voltage of the bus capacitor is charged to a predetermined value, the control circuit is configured to output the control signals so that the first switch unit and the second switch unit are turned off, and the common terminal of the single-pole double-throw relay is connected to the normally open contact of the single-pole double-throw relay.
9. The power conversion device of claim 7, wherein, During the working process of the power conversion device and when it is required to switch between the first power source and the second power source, the control circuit is configured to output the control signals so that: the second switch unit is turned on, and the first switch unit is turned off; at the same time or subsequently, the common terminal of the single-pole double-throw relay is switched from being connected to the normally open contact of the single-pole double-throw relay to being connected to the normally closed contact of the single-pole double-throw relay. then the second switch unit is turned off; simultaneously or subsequently, switching between the first power source and the second power source is enabled; then the second switch unit is turned on; simultaneously or subsequently, the common terminal of the single-pole double-throw relay is switched from the normally closed contact to the normally open contact connected to the single-pole double-throw relay; then the second switch unit is turned off.
10. A power conversion device, characterized by comprising: comprising: a relay switching unit comprising at least one relay, having a first input terminal, a second input terminal and an output terminal, the first input terminal being used for connecting a first power source, the second input terminal being used for connecting a second power source; a single-pole double-throw relay comprising a common terminal, a normally closed contact and a normally open contact, the output terminal of the relay switching unit being connected to the common terminal of the single-pole double-throw relay; a switch-resistor series branch comprising a first switch unit and a resistor unit connected in series, the first terminal of the switch-resistor series branch being connected to the normally closed contact, the second terminal of the switch-resistor series branch being connected to the normally open contact; a power supply conversion circuit, the input terminal of which being connected to the second terminal of the switch-resistor series branch, wherein the output terminal of the power supply conversion circuit comprises a bus capacitor; a control circuit for outputting control signals for controlling the single-pole double-throw relay, the first switch unit and the power supply conversion circuit.
11. The power conversion device of claim 10, wherein, At startup, the control circuit is configured to output control signals such that: the first switch unit is turned on, and the common terminal of the single-pole double-throw relay is connected to the normally closed contact of the single-pole double-throw relay. When the voltage of the bus capacitor is charged to a predetermined value, the control circuit is configured to output control signals such that: the first switch unit is turned off, and the common terminal of the single-pole double-throw relay is connected to the normally open contact of the single-pole double-throw relay.
12. The power conversion device of claim 10, wherein, During the operation of the power supply conversion device, and when it is necessary to switch between the first power source and the second power source, the control circuit is configured to output control signals: such that the first switch unit is turned off, and the power supply conversion circuit is not operated; simultaneously or subsequently, the common terminal of the single-pole double-throw relay is switched from the normally open contact to the normally closed contact connected to the single-pole double-throw relay; simultaneously or subsequently, switching between the first power source and the second power source is enabled; simultaneously or subsequently, the common terminal of the single-pole double-throw relay is switched from the normally closed contact to the normally open contact connected to the single-pole double-throw relay; then the power supply conversion circuit is operated.