Single-phase and three-phase input compatible switching power supply output circuit

Abstract

The utility model provides a switching power supply output circuit compatible with single-phase and three-phase input, which relates to the field of switching power supplies and comprises an alternating current input end, a rectifying circuit, a direct current output end, an input voltage detection unit, a voltage boosting unit and a mode switching switch unit, the input voltage detection unit is electrically connected with the alternating current input end, one end of the input voltage detection unit is electrically connected with the alternating current input end, the other end of the input voltage detection unit is electrically connected with the rectification circuit, and the mode switching switch unit is used for connecting the voltage boosting unit to the rectification circuit during single-phase input. When the mode change-over switch unit is in three-phase input, the connection between the voltage lifting unit and the rectifying circuit is cut off, and the single-phase input and three-phase input compatibility of the alternating-current input type switching power supply is realized.

Description

Technical Field

[0001] The utility model relates to the field of switching power supplies, in particular to a switching power supply output circuit compatible with single-phase and three-phase inputs. Background Art

[0002] AC input switching power supplies are divided into three-phase input and single-phase input. The three-phase input AC input switching power supply uses high-frequency pulse width modulation conversion technology in the main circuit, and the AC-DC-AC-DC main circuit topology to achieve the effect of DC input. The single-phase input AC input switching power supply uses high-frequency pulse width modulation conversion technology in the main circuit, and the AC-DC-AC-DC main circuit topology to achieve the effect of DC input.

[0003] Existing AC input switching power supplies cannot switch between three-phase input and single-phase input and need to be designed separately. Under certain specific working conditions, such as when a three-phase input is missing, the AC input switching power supply will not work properly.

[0004] Therefore, it is necessary to provide a switching power supply output circuit that is compatible with single-phase and three-phase inputs, so as to achieve compatibility with single-phase input and three-phase input of an AC input switching power supply. Utility Model Content

[0005] The utility model provides a switching power supply output circuit compatible with single-phase and three-phase inputs, comprising an AC input end, a rectifier circuit, a DC output end, an input voltage detection unit, a voltage boosting unit and a mode switching switch unit, wherein the AC input end, the rectifier circuit and the DC output end are electrically connected in sequence, the input voltage detection unit is electrically connected to the AC input end, one end of the input voltage detection unit is electrically connected to the AC input end, and the other end of the input voltage detection unit is electrically connected to the rectifier circuit, and the mode switching switch unit is used to connect the voltage boosting unit to the rectifier circuit when single-phase input is used, and the mode switching switch unit disconnects the voltage boosting unit from the rectifier circuit when three-phase input is used.

[0006] Furthermore, the input voltage detection unit includes a first rectifier diode component and an input voltage sensor, wherein the first rectifier diode component is electrically connected to the AC input end, and the output end of the first rectifier diode component is electrically connected to the input voltage sensor.

[0007] Furthermore, the rectifier circuit includes a rectifier bridge, an inductor, a first thin film capacitor, a second thin film capacitor, an inverter, a transformer and a third rectifier diode assembly, wherein the rectifier bridge is electrically connected to the AC input end, and the rectifier bridge, inverter, transformer and third rectifier diode assembly are electrically connected in sequence, one end of the first thin film capacitor is electrically connected to the positive output end of the rectifier bridge, the other end of the first thin film capacitor is electrically connected to the negative output end of the rectifier bridge, one end of the second thin film capacitor is electrically connected to the positive output end of the rectifier bridge, the other end of the second thin film capacitor is electrically connected to the negative output end of the rectifier bridge, and the inductor is connected in series between the positive output end of the rectifier bridge and the first thin film capacitor.

[0008] Furthermore, the voltage raising unit includes a current limiting resistor component, a second rectifier diode component and an electrolytic capacitor component electrically connected in sequence, wherein the input end of the current limiting resistor component is electrically connected to the AC input end, the positive output end of the electrolytic capacitor component is electrically connected to one end of the first thin film capacitor electrically connected to the positive output end of the rectifier bridge, and the negative output end of the electrolytic capacitor component is electrically connected to one end of the first thin film capacitor electrically connected to the negative output end of the rectifier bridge.

[0009] Furthermore, the mode switching switch unit includes a first switch component, a second switch component and a third switch component, wherein the first switch component is connected in series between the AC input end and the rectifier bridge, the second switch component is connected in series between the AC input end and the current limiting resistor component, and the third switch component is connected in series between the electrolytic capacitor component and the first film capacitor.

[0010] Furthermore, during three-phase input, the first switch component is in a closed state, and the second switch component and the third switch component are in an open state.

[0011] Furthermore, during single-phase input, the third switch component and the second switch component are in a closed state; after the electrolytic capacitor component is charged, the first switch component and the third switch component are in a closed state, and the second switch component is in an open state.

[0012] Furthermore, when the three-phase input is converted to single-phase input, the first switch component and the second switch component are in a closed state. After the electrolytic capacitor component is charged, the first switch component and the third switch component are in a closed state, and the second switch component is in an open state.

[0013] Furthermore, an output current detector is included, and the output current detector is electrically connected to the DC output end.

[0014] Furthermore, it also includes an output voltage detector, which is electrically connected to the DC output end.

[0015] Compared with the prior art, the present invention provides a switching power supply output circuit compatible with single-phase and three-phase inputs, which has at least the following beneficial effects:

[0016] Traditional switching power supplies may not function properly if a phase is missing from a three-phase input. However, this circuit, through its voltage booster and mode switching unit, provides sufficient voltage support for single-phase input, ensuring stable operation even in phase-loss conditions. This enhances the power supply's reliability and stability, reducing the risk of equipment failure due to abnormal input voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] This specification will be further described in the form of exemplary embodiments, which will be described in detail with reference to the accompanying drawings. These embodiments are not limiting, and in these embodiments, like numbers represent like structures, wherein:

[0018] Figure 1 This is a circuit diagram of a switching power supply output circuit compatible with single-phase and three-phase inputs according to some embodiments of this specification. DETAILED DESCRIPTION

[0019] To more clearly illustrate the technical solutions of the embodiments of this specification, the following briefly describes the drawings required for describing the embodiments. Obviously, the drawings described below are merely examples or embodiments of this specification. Those skilled in the art can apply this specification to other similar scenarios based on these drawings without inventive effort. Unless otherwise apparent from the context or otherwise noted, the same reference numerals in the figures represent the same structure or operation.

[0020] A switching power supply output circuit compatible with single-phase and three-phase inputs may include an AC input terminal, a rectifier circuit, a DC output terminal, an input voltage detection unit, a voltage boosting unit, and a mode switching switch unit, wherein the AC input terminal, the rectifier circuit, and the DC output terminal are electrically connected in sequence, the input voltage detection unit is electrically connected to the AC input terminal, one end of the input voltage detection unit is electrically connected to the AC input terminal, and the other end of the input voltage detection unit is electrically connected to the rectifier circuit; the mode switching switch unit is used to connect the voltage boosting unit to the rectifier circuit when single-phase input is used, and the mode switching switch unit is used to disconnect the voltage boosting unit from the rectifier circuit when three-phase input is used.

[0021] In some embodiments, the input voltage detection unit includes a first rectifier diode component D1 and an input voltage sensor VS1, wherein the first rectifier diode component D1 is electrically connected to the AC input end, and the output end of the first rectifier diode component D1 is electrically connected to the input voltage sensor VS1.

[0022] Specifically, the AC input passes through the first rectifier diode assembly D1, and the rectified voltage is input to the input voltage sensor VS1. The operator or controller can determine whether the input is three-phase or single-phase based on the output of the input voltage sensor VS1. For example, for a single-phase 380V±15% voltage, when the voltage is at +15% high, the average value after rectification by the first rectifier diode assembly D1 is approximately 393VDC. For a three-phase 380V±15% voltage, when the voltage is at -15% low, the average value after rectification by the first rectifier diode assembly D1 is approximately 436VDC. Both average values ​​are collected by the input voltage sensor VS1. Because there is a 43V difference between 393V and 436V, this is defined as a common range; within this voltage range, no switching is required. If the collected voltage is less than 393V, it is determined that the three-phase power supply is insufficient, indicating that the input is not three-phase. If the collected voltage is greater than 436V, it is determined that the three-phase power supply is sufficient, indicating that the input is not single-phase.

[0023] Figure 1 This is a circuit diagram of a switching power supply output circuit compatible with single-phase and three-phase inputs according to some embodiments of this specification, such as Figure 1 As shown, in some embodiments, the rectifier circuit includes a rectifier bridge BR1, an inductor L1, a first thin film capacitor C1, a second thin film capacitor C2, an inverter Q1, a transformer T1 and a third rectifier diode assembly D10, wherein the rectifier bridge BR1 is electrically connected to the AC input end, the rectifier bridge BR1, the inverter Q1, the transformer T1 and the third rectifier diode assembly D10 are electrically connected in sequence, one end of the first thin film capacitor C1 is electrically connected to the positive output end of the rectifier bridge BR1, the other end of the first thin film capacitor C1 is electrically connected to the negative output end of the rectifier bridge BR1, one end of the second thin film capacitor C2 is electrically connected to the positive output end of the rectifier bridge BR1, the other end of the second thin film capacitor C2 is electrically connected to the negative output end of the rectifier bridge BR1, and the inductor L1 is connected in series between the positive output end of the rectifier bridge BR1 and the first thin film capacitor C1.

[0024] Specifically, the rectifier bridge BR1 converts input alternating current (AC) into direct current (DC). Consisting of six diodes, BR1 converts both the positive and negative half-cycles of the AC power into positive DC. Inductor L1 acts as a filter, smoothing the rectified DC power and reducing ripple. Inductor L1 dampens rapid current changes, thereby helping to reduce current fluctuations caused by the AC component during the rectification process. The first and second film capacitors C1 and C2 further smooth the DC power, especially at high frequencies. Together with inductor L1, they form a low-pass filter, allowing the DC component to pass while blocking high-frequency AC components. Inverter Q1 converts the smoothed DC power back into AC power. By controlling the switching states of the IGBTs, AC power with a specific frequency and waveform can be generated. Transformer T1 reduces the voltage of the inverted AC power. The primary side (input side) of transformer T1 is connected to the output of inverter Q1, while the secondary side (output side) provides stepped-down DC power. The third rectifier diode assembly D10 rectifies the output of the transformer T1.

[0025] like Figure 1 As shown, in some embodiments, a switching power supply output circuit compatible with single-phase and three-phase inputs may further include an output current detector and an output voltage detector, wherein the output current detector is electrically connected to the DC output terminal, and the output voltage detector is electrically connected to the DC output terminal to collect the output current feedback signal and the output voltage feedback signal.

[0026] like Figure 1 As shown, in some embodiments, the voltage raising unit includes a current limiting resistor component, a second rectifier diode component D2 and an electrolytic capacitor component electrically connected in sequence, wherein the input end of the current limiting resistor component is electrically connected to the AC input end, the positive output end of the electrolytic capacitor component is electrically connected to one end of the first film capacitor electrically connected to the positive output end of the rectifier bridge, and the negative output end of the electrolytic capacitor component is electrically connected to one end of the first film capacitor electrically connected to the negative output end of the rectifier bridge. Wherein, the electrolytic capacitor component may include a plurality of electrolytic capacitors, for example, electrolytic capacitors E1, E2, E3, and E4. The capacitance value of the electrolytic capacitor is calculated based on the load current, at least 4700uF600V, and the quantity is on demand. For example: a 4700uF600V electrolytic capacitor is required when the load power is about 6KW. The current limiting resistor component may include a plurality of current limiting resistors, for example, current limiting resistor R1, current limiting resistor R2 and current limiting resistor R3. The function of the current limiting resistor is to limit the current. After current limiting, a small current is used to charge the electrolytic capacitor component. Therefore, the resistance value of the current limiting resistor is configured as needed to keep the charging current of the electrolytic capacitor component within 10A.

[0027] In some embodiments, the mode switching switch unit includes a first switch component KM1, a second switch component KM2 and a third switch component KM3, wherein the first switch component KM1 is connected in series between the AC input end and the rectifier bridge, the second switch component KM2 is connected in series between the AC input end and the current limiting resistor component, and the third switch component KM3 is connected in series between the electrolytic capacitor component and the first film capacitor C1.

[0028] In some embodiments, during three-phase input, the first switch component KM1 is in a closed state, and the second switch component KM2 and the third switch component KM3 are in an open state.

[0029] In some embodiments, during single-phase input, the third switch component KM3 and the second switch component KM2 are in a closed state. After the electrolytic capacitor component is charged, the first switch component KM1 and the third switch component KM3 are in a closed state, and the second switch component KM2 is in an open state.

[0030] Specifically, when single-phase input is used, the electrolytic capacitor assembly is directly incorporated. Because the capacitance of the electrolytic capacitor is large, suddenly connecting it and then powering it on will cause overcharging, resulting in high voltage peaks and large currents, which can easily damage other components. Therefore, the third switch assembly KM3 is first closed to make the electrolytic capacitor assembly equal to the potential of the first film capacitor C1 and the second film capacitor C2. Then the second switch assembly KM2 is closed, and the electrolytic capacitor assembly and the first film capacitor C1 and the second film capacitor C2 are charged after the current is limited by the current limiting resistor assembly. When the three-phase 380V input is used, the DC voltage entering the inverter Q1 after rectification is approximately 513V. When there is a phase loss, it is two-phase 380V. The voltage entering the inverter Q1 after the rectifier bridge is approximately 342V, which will result in insufficient power voltage. After the electrolytic capacitor assembly is charged, the first switch assembly KM1 and the third switch assembly KM3 are in the closed state, and the electrolytic capacitor assembly is incorporated into the DC power at the back end of the rectifier bridge. In this way, when the two-phase 380V input is used, the output voltage will be raised to approximately 510V. Meet the power voltage requirements.

[0031] In some embodiments, when three-phase input is converted to single-phase input, the first switch assembly KM1 and the second switch assembly KM2 are in the closed state. After the electrolytic capacitor assembly is charged, the first switch assembly KM1 and the third switch assembly KM3 are in the closed state, and the second switch assembly KM2 is in the open state. Unlike the scenario where only single-phase input is used, when three-phase input is converted to single-phase input, there will be a certain amount of electricity in the electrolytic capacitor assembly, and the voltage is relatively high, about 513V, and the electrolytic capacitor cannot be directly incorporated. Otherwise, it is easy to cause voltage unevenness, overcharging, or even sparking. After the electrolytic capacitor assembly is charged and maintains a certain voltage, the third switch assembly KM3 is controlled to be closed to incorporate the electrolytic capacitor assembly into the main circuit.

[0032] Finally, it should be understood that the embodiments described in this specification are intended only to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, by way of example and not limitation, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly described and illustrated in this specification.

Claims

1. A switching power supply output circuit compatible with single-phase and three-phase inputs, characterized in that: It includes an AC input end, a rectifier circuit, a DC output end, an input voltage detection unit, a voltage boosting unit and a mode switching switch unit, wherein the AC input end, the rectifier circuit and the DC output end are electrically connected in sequence, the input voltage detection unit is electrically connected to the AC input end, one end of the input voltage detection unit is electrically connected to the AC input end, and the other end of the input voltage detection unit is electrically connected to the rectifier circuit. The mode switching switch unit is used to connect the voltage boosting unit to the rectifier circuit when single-phase input is used, and the mode switching switch unit disconnects the voltage boosting unit from the rectifier circuit when three-phase input is used.

2. The switching power supply output circuit compatible with single-phase and three-phase inputs according to claim 1, characterized in that: The input voltage detection unit includes a first rectifier diode component and an input voltage sensor, wherein the first rectifier diode component is electrically connected to the AC input end, and the output end of the first rectifier diode component is electrically connected to the input voltage sensor.

3. The switching power supply output circuit compatible with single-phase and three-phase inputs according to claim 1, characterized in that: The rectifier circuit includes a rectifier bridge, an inductor, a first thin film capacitor, a second thin film capacitor, an inverter, a transformer and a third rectifier diode assembly, wherein the rectifier bridge is electrically connected to the AC input end, and the rectifier bridge, inverter, transformer and third rectifier diode assembly are electrically connected in sequence, one end of the first thin film capacitor is electrically connected to the positive output end of the rectifier bridge, the other end of the first thin film capacitor is electrically connected to the negative output end of the rectifier bridge, one end of the second thin film capacitor is electrically connected to the positive output end of the rectifier bridge, the other end of the second thin film capacitor is electrically connected to the negative output end of the rectifier bridge, and the inductor is connected in series between the positive output end of the rectifier bridge and the first thin film capacitor.

4. The switching power supply output circuit compatible with single-phase and three-phase inputs according to claim 3, characterized in that: The voltage raising unit includes a current limiting resistor component, a second rectifier diode component and an electrolytic capacitor component electrically connected in sequence, wherein the input end of the current limiting resistor component is electrically connected to the AC input end, the positive output end of the electrolytic capacitor component is electrically connected to one end of the first thin film capacitor electrically connected to the positive output end of the rectifier bridge, and the negative output end of the electrolytic capacitor component is electrically connected to one end of the first thin film capacitor electrically connected to the negative output end of the rectifier bridge.

5. The switching power supply output circuit compatible with single-phase and three-phase inputs according to claim 4, characterized in that: The mode switching switch unit includes a first switch component, a second switch component and a third switch component, wherein the first switch component is connected in series between the AC input end and the rectifier bridge, the second switch component is connected in series between the AC input end and the current limiting resistor component, and the third switch component is connected in series between the electrolytic capacitor component and the first film capacitor.

6. The switching power supply output circuit compatible with single-phase and three-phase inputs according to claim 5, characterized in that: During three-phase input, the first switch component is in a closed state, and the second switch component and the third switch component are in an open state.

7. The switching power supply output circuit compatible with single-phase and three-phase inputs according to claim 5, characterized in that: During single-phase input, the third switch component and the second switch component are in a closed state. After the electrolytic capacitor component is charged, the first switch component and the third switch component are in a closed state, and the second switch component is in an open state.

8. The switching power supply output circuit compatible with single-phase and three-phase inputs according to claim 5, characterized in that: When the three-phase input is converted to single-phase input, the first switch component and the second switch component are in a closed state. After the electrolytic capacitor component is charged, the first switch component and the third switch component are in a closed state, and the second switch component is in an open state.

9. A switching power supply output circuit compatible with single-phase and three-phase inputs according to any one of claims 1 to 8, characterized in that: It also includes an output current detector, which is electrically connected to the DC output terminal.

10. A switching power supply output circuit compatible with single-phase and three-phase inputs according to any one of claims 1 to 8, characterized in that: It also includes an output voltage detector, which is electrically connected to the DC output terminal.

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