Load power supply circuit based on commercial power and inverter

Abstract

The embodiment of the utility model provides a load power supply circuit based on commercial power and an inverter. The load power supply circuit comprises a commercial power supply circuit and an inverter power supply circuit, the inverter power supply circuit comprises an inverter circuit, a capacitive load circuit and a control circuit. Through the cooperation of the control circuit and the inverter circuit, when the commercial power supply circuit is switched to the inverter power supply circuit for power supply, the inverter voltage output by the inverter circuit can be basically consistent with the voltage of the first end of the capacitive load circuit, the situation that large surge current appears in the capacitive load circuit, the inverter circuit and a load are damaged is avoided, and the service life of the inverter circuit is prolonged. And the safety of the load power supply circuit is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the technical field of electronic circuits, and in particular to a load power supply circuit based on AC power and an inverter. Background Art

[0002] The load power supply can be AC ​​power from the mains directly supplying power to the load, or a DC power supply can supply power to the load through an inverter function. Specifically, the DC power supply is converted into AC power through an inverter to supply power to the load.

[0003] When the AC power is supplying power to the load, if the AC power is abnormal, it is necessary to disconnect the AC power and switch to the DC power supply to supply power to the load. However, when the AC power is disconnected, due to the presence of the capacitive load, there is a certain residual voltage at both ends of the capacitive load. The DC power supply outputs the inverter voltage through the inverter. If the difference between the inverter voltage and the residual voltage is too large, a large surge current will be generated, causing damage to the inverter and the capacitive load. Utility Model Content

[0004] In order to overcome the problems existing in the related art, the present application provides a load power supply circuit based on AC power and an inverter, which can avoid large surge currents and improve the safety of the load power supply circuit.

[0005] According to one aspect of an embodiment of the present application, there is provided a load power supply circuit based on a mains supply and an inverter, comprising a mains supply circuit and an inverter supply circuit;

[0006] The first input end of the mains power supply circuit is connected to the live wire of the alternating current, the second input end of the mains power supply circuit is connected to the neutral wire of the alternating current, the first output end of the mains power supply circuit is connected to the first end of the load, and the second output end of the mains power supply circuit is connected to the second end of the load;

[0007] The inverter power supply circuit includes an inverter circuit, a capacitive load circuit and a control circuit; a first input terminal of the inverter circuit is connected to the positive electrode of the DC power supply, a second input terminal of the inverter circuit is connected to the negative electrode of the DC power supply, a signal driving terminal of the inverter circuit is connected to the control signal output terminal of the control circuit, a first output terminal of the inverter circuit is connected to the first terminal of the capacitive load circuit, and a second output terminal of the inverter circuit is connected to the second terminal of the capacitive load circuit; a signal sampling terminal of the control circuit is connected to the first terminal of the capacitive load circuit; a third terminal of the capacitive load circuit is connected to the first terminal of the load, and a fourth terminal of the capacitive load circuit is connected to the second terminal of the load;

[0008] When the AC power supply circuit switches to the inverter power supply circuit, the control circuit samples the voltage of the first end of the capacitive load circuit through the signal sampling end, and outputs a control signal through the control signal output end to drive the inverter circuit to output an inverter voltage to power the load.

[0009] The embodiment of the present application cooperates with the control circuit and the inverter circuit. When the AC power supply circuit is switched to the inverter power supply circuit, the inverter voltage output by the inverter circuit can be basically consistent with the voltage of the first end of the capacitive load circuit, thereby avoiding large surge current in the capacitive load circuit, damaging the inverter circuit and the load, and improving the safety of the load power supply circuit.

[0010] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application.

[0011] In order to better understand and implement the present invention, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A schematic diagram of the circuit structure of a load power supply circuit based on mains power and an inverter according to an embodiment of the present application;

[0013] Figure 2 The specific circuit structure diagram of the load power supply circuit based on AC power and inverter shown in the embodiment of the present application. DETAILED DESCRIPTION

[0014] In order to make the objectives, technical solutions and advantages of the present application more clear, the embodiments of the present application will be further described in detail below with reference to the accompanying drawings.

[0015] It should be clear that the described embodiments are only 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 ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0016] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements.

[0017] In the description of the present application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. The singular forms of "a", "said", and "the" used in the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. The words "if" / "if" used herein can be interpreted as "at the time of" or "when" or "in response to determination". In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships can exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0018] See also Figure 1 , which is a circuit structure diagram of a load power supply circuit based on mains power and an inverter shown in an embodiment of the present application. The load power supply circuit based on mains power and an inverter in an embodiment of the present application is applied to power supply of various loads, and is mainly used to provide a stable AC voltage for the load. Specifically, the load power supply circuit based on mains power and an inverter in an embodiment of the present application includes a mains power supply circuit 100 and an inverter power supply circuit 200.

[0019] The first input end of the mains power supply circuit 100 is connected to the live wire of the alternating current, the second input end of the mains power supply circuit 100 is connected to the neutral wire of the alternating current, the first output end of the mains power supply circuit 100 is connected to the first end of the load, and the second output end of the mains power supply circuit 100 is connected to the second end of the load;

[0020] The inverter power supply circuit 200 includes an inverter circuit 210, a capacitive load circuit 220 and a control circuit 230; a first input terminal of the inverter circuit 210 is connected to the positive electrode of the DC power supply, a second input terminal of the inverter circuit 210 is connected to the negative electrode of the DC power supply, a signal driving terminal of the inverter circuit 210 is connected to the control signal output terminal of the control circuit 230, a first output terminal of the inverter circuit 210 is connected to the first terminal of the capacitive load circuit 220, and a second output terminal of the inverter circuit 210 is connected to the second terminal of the capacitive load circuit 220; a signal sampling terminal of the control circuit 230 is connected to the first terminal of the capacitive load circuit 220; a third terminal of the capacitive load circuit 220 is connected to the first terminal of the load, and a fourth terminal of the capacitive load circuit 220 is connected to the second terminal of the load;

[0021] When the AC power supply circuit 100 switches to the inverter power supply circuit 200 for power supply, the control circuit 230 samples the voltage of the first end of the capacitive load circuit 220 through the signal sampling end, and outputs a control signal through the control signal output end to drive the inverter circuit 210 to output an inverter voltage to power the load.

[0022] The AC power supply circuit 100 is used to directly output AC power to supply power to the load.

[0023] The inverter power supply circuit 200 is used to convert a DC power supply into an AC power supply to supply power to a load. Specifically, the inverter power supply circuit 200 includes an inverter circuit 210, a capacitive load circuit 220, and a control circuit 230. The control circuit 230 is used to collect the voltage at the first end of the capacitive load circuit 220, and output a control signal to drive the inverter circuit 210 to output an inverter voltage according to the voltage at the first end of the capacitive load circuit 220. The inverter circuit 210 is used to output an inverter voltage according to the control signal. The control circuit 230 is a phase-locked loop.

[0024] When an abnormality is detected in the AC power supply circuit 100, for example, the voltage, frequency or waveform of the AC power does not meet the output quality requirements, the AC power needs to be disconnected. However, due to the presence of the capacitive load, there will be a residual voltage across the capacitive load. When switching to the inverter power supply circuit 200 to power the load, if the difference between the voltage output by the inverter power supply circuit 200 and the residual voltage is too large, it will cause an excessive surge circuit in the circuit, which will damage the inverter power supply circuit 200 and the load.

[0025] In the embodiment of the present application, through the cooperation of the control circuit 230 and the inverter circuit 210, when the AC power supply circuit 100 switches to the inverter power supply circuit 200 for power supply, the inverter voltage output by the inverter circuit 210 can be basically consistent with the voltage of the first end of the capacitive load circuit 220, thereby avoiding the occurrence of large surge current in the capacitive load circuit 220, damaging the inverter circuit 210 and the load, and improving the safety of the load power supply circuit.

[0026] See also Figure 2 , which is a schematic diagram of a specific circuit structure of a load power supply circuit based on mains power and an inverter shown in an embodiment of the present application; Figure 2 The structures of various parts of this application are described in detail.

[0027] In one embodiment, the mains power supply circuit 100 includes a third filter circuit 110, a first relay RL1 and a second relay RL3; the first relay RL1 includes a first control coil, a first contact and a second contact, and the second relay RL3 includes a second control coil, a third contact, a fourth contact and a fifth contact;

[0028] A first end of the third filter circuit 110 is connected to the live wire of the alternating current, a second end of the third filter circuit 110 is connected to the neutral wire of the alternating current, a third end of the third filter circuit 110 is connected to the first contact, the second contact is connected to the first end of the load, a fourth end of the third filter circuit 110 is connected to the third contact, the fourth contact is connected to the second end of the load, and the fifth contact is grounded; a first end of the first control coil is connected to a DC power supply, a second end of the first control coil is connected to a first end of the first switch circuit, a second end of the first switch circuit is connected to a first control port of the single-chip microcomputer, and a third end of the first switch circuit is grounded; a first end of the second control coil is connected to a DC power supply, a second end of the second control coil is connected to a first end of the second switch circuit, a second end of the second switch circuit is connected to a second control port of the single-chip microcomputer, and a third end of the second switch circuit is grounded.

[0029] The third filter circuit 110 is used to filter out high-frequency interference in the alternating current, and the first relay RL1 and the second relay RL3 cooperate with each other to control the on and off of the AC power supply circuit 100 to supply power to the load.

[0030] Specifically, when the AC power supply circuit 100 supplies power to the load, the first control port of the single-chip microcomputer outputs a high level, controls the first switch circuit to be turned on, thereby energizing the first control coil and connecting the first contact to the second contact; the second control port of the single-chip microcomputer outputs a high level, controls the second switch circuit to be turned on, thereby energizing the second control coil and connecting the third contact to the fourth contact.

[0031] When the AC power supply circuit 100 is powered off, the first control port of the single-chip microcomputer outputs a low level, controlling the first switch circuit to be disconnected, so that no current flows through the first control coil, and the first contact is disconnected from the second contact; the second control port of the single-chip microcomputer outputs a high level, controlling the second switch circuit to be disconnected, so that no current flows through the second control coil, the third contact is disconnected from the fourth contact, and the third contact is connected to the fifth contact.

[0032] In one embodiment, the third filtering circuit 110 includes a thirteenth capacitor C24, a fourteenth capacitor C19 and a fifteenth capacitor C39, a first end of the thirteenth capacitor C24 is connected to the live wire of the alternating current, a second end of the thirteenth capacitor C24 is connected to the neutral wire of the alternating current, a first end of the fourteenth capacitor C19 is connected to the live wire of the alternating current, a second end of the fourteenth capacitor C19 is connected to the first end of the fifteenth capacitor C39 and the ground, and a second end of the fifteenth capacitor C39 is connected to the neutral wire of the alternating current.

[0033] Specifically, the thirteenth capacitor C24 is connected between the live wire and the neutral wire to buffer the voltage fluctuation of the AC power and filter out the high-frequency interference in the AC power. The fourteenth capacitor C19 and the fifteenth capacitor C39 are connected in series and connected between the live wire and the neutral wire to form a safety capacitor to filter out the high-frequency interference in the AC power.

[0034] In one embodiment, the inverter circuit 210 includes an inverter 212 , a first filter circuit 214 , and a second filter circuit 216 ;

[0035] The first end of the inverter 212 is the first input end of the inverter circuit 210, which is used to connect to the positive electrode of the DC power supply; the second end of the inverter 212 is the second input end of the inverter circuit 210, which is used to connect to the negative electrode of the DC power supply; the third end of the inverter 212 is the signal driving end of the inverter circuit 210, which is used to connect to the control circuit 230 ( Figure 2 The fourth end of the inverter 212 is connected to the first end of the second filter circuit 216, and the fifth end of the inverter 212 is the second output end of the inverter circuit 210, which is used to be connected to the second end of the capacitive load circuit 220; the second end of the second filter circuit 216 is connected to the first end of the capacitive load circuit 220; the first end of the first filter circuit 214 is connected to the positive electrode of the DC power supply, and the second end of the first filter circuit 214 is connected to the negative electrode of the DC power supply.

[0036] The AC power outputted by the inverter 212 is an unsmooth, non-sinusoidal AC power with many sawtooth waves. The second filter circuit 216 is used to filter and freewheel the AC power outputted by the inverter 212, and filter the intermittent, sawtooth AC current into a continuous and smooth current. The first filter circuit 214 is used to filter the noise at both ends of the DC power supply.

[0037] Specifically, the control signal output terminal of the control circuit 230 outputs a control signal to the signal driving terminal of the inverter circuit 210, and the inverter circuit 210 outputs alternating current, which is filtered and freewheeled by the second filter circuit 216 to obtain a continuous and smooth alternating current.

[0038] In one embodiment, the control signal output terminal of the control circuit 230 includes a first control signal output terminal, a second control signal output terminal, a third control signal output terminal and a fourth control signal output terminal; the third terminal of the inverter 212 includes a first signal driving terminal, a second signal driving terminal, a third signal driving terminal and a fourth signal driving terminal;

[0039] The inverter 212 includes a first transistor D36, a second transistor Q14, a third transistor Q6, a fourth transistor Q16, a first diode D36, a second diode D3, a third diode D2, a fourth diode D4, a first resistor R4, a second resistor R16, a third resistor R11, a fourth resistor R24, a fifth resistor R3, a sixth resistor R34, a seventh resistor R6, an eighth resistor R1, a ninth resistor R13, a tenth resistor R26, an eleventh resistor R5, and a twelfth resistor R36;

[0040] The collector of the first triode Q4 is connected to the positive electrode of the DC power supply, the base of the first triode Q4 is connected to the first end of the second resistor R16 through the first resistor R4, the second end of the second resistor R16 is a first signal driving end, which is used to be connected to the first control signal output end, the emitter of the first triode Q4 is connected to the collector of the second triode Q14, the first diode D36 is connected in parallel to the two ends of the second resistor R16, and the third resistor R11 is connected between the base of the first triode Q4 and the emitter of the first triode Q4;

[0041] The base of the second triode Q14 is connected to the first end of the fifth resistor R3 through the fourth resistor R24, the second end of the fifth resistor R3 is a second signal driving end, which is used to be connected to the second control signal output end, the emitter of the second triode Q14 is connected to the negative electrode of the DC power supply, the second diode D3 is connected in parallel to the two ends of the fifth resistor R3, and the sixth resistor R34 is connected between the base of the second triode Q14 and the emitter of the second triode Q14;

[0042] The collector of the third triode Q6 is connected to the positive electrode of the DC power supply, the base of the third triode Q6 is connected to the first end of the eighth resistor R1 through the seventh resistor R6, the second end of the eighth resistor R1 is a third signal driving end, which is used to be connected to the third control signal output end, the emitter of the third triode Q6 is connected to the collector of the fourth triode Q16 and the first end of the capacitive load circuit 220, the third diode D2 is connected in parallel to the two ends of the eighth resistor R1, and the ninth resistor R13 is connected between the base of the third triode Q6 and the emitter of the third triode Q6;

[0043] The base of the fourth triode Q16 is connected to the first end of the eleventh resistor R5 through the tenth resistor R26. The second end of the eleventh resistor R5 is a fourth signal driving end, which is used to be connected to the fourth control signal output end. The emitter of the fourth triode Q16 is connected to the negative electrode of the DC power supply. The fourth diode D4 is connected in parallel at both ends of the eleventh resistor R5. The twelfth resistor R36 is connected between the base of the fourth triode Q16 and the emitter of the fourth triode Q16.

[0044] Among them, the first transistor Q4, the second transistor Q14, the third transistor Q6, and the fourth transistor Q16 are all IGBT transistors.

[0045] Specifically, the first control signal output terminal, the second control signal output terminal, the third control signal output terminal and the fourth control signal output terminal of the control circuit 230 respectively output pulse width modulation signals for controlling the conduction and disconnection of the first triode Q4, the second triode Q14, the third triode Q6 and the fourth triode Q16. After the first triode Q4, the second triode Q14, the third triode Q6 and the fourth triode Q16 are turned on, the DC power supply can be converted into AC power.

[0046] In one embodiment, the first filter circuit 214 includes a third capacitor C14, a fourth capacitor C15, a thirteenth resistor R17 and a fourteenth resistor R18; the third capacitor C14, the fourth capacitor C15, the thirteenth resistor R17 and the fourteenth resistor R18 are all connected in parallel between the first end of the inverter 212 and the second end of the inverter 212.

[0047] Specifically, the third capacitor C14, the fourth capacitor C15, the thirteenth resistor R17 and the fourteenth resistor R18 are connected in parallel to filter out high-frequency interference in the circuit.

[0048] In one embodiment, the second filtering circuit 216 includes a current sensor HCT2, a first inductor L7, a second inductor L2, a first capacitor and a second capacitor; the first end of the current sensor HCT2 is the first end of the second filtering circuit 216, which is used to be connected to the fourth end of the inverter 212, the second end of the current sensor HCT2 is connected to the first end of the first inductor L7, the first end of the first inductor L7 is the second end of the second filtering circuit 216, which is used to be connected to the first end of the capacitive load circuit 220; the third end of the current sensor HCT2 is grounded via the first capacitor, the fourth end of the current sensor HCT2 and the fifth end of the current sensor HCT2 are respectively connected to the first signal sampling chip, the sixth end of the current sensor HCT2 is grounded, one end of the second capacitor is connected to the third end of the current sensor HCT2 and the DC power supply, and the other end of the second capacitor is grounded; the first end of the second inductor L2 is connected to the fourth end of the inverter 212, and the second end of the second inductor L2 is connected to the first end of the capacitive load circuit 220.

[0049] Specifically, the current sensor HCT2 is a Hall current sensor, and the first signal sampling chip is used to collect high-frequency AC current signals. The first inductor L7 and the second inductor L2 are used to hinder the change of AC power, so that the AC power fluctuates slowly. The first capacitor and the second capacitor are used to filter out common-mode interference.

[0050] In one embodiment, the capacitive load circuit 220 includes a fifteenth resistor R32, a seventh capacitor C20, an eighth capacitor C7, a ninth capacitor C6, a tenth capacitor C27, an eleventh capacitor C17, a twelfth capacitor C33, a common mode inductor L4, a first varistor MOV3, a second varistor MOV2, a third varistor MOV5 and a gas discharge tube GT2;

[0051] A first end of the common mode inductor L4 is connected to a second end of the second filter circuit 216, a second end of the common mode inductor L4 is connected to a fifth end of the inverter 212, a third end of the common mode inductor L4 is connected to a first end of the load, and a fourth end of the common mode inductor L4 is connected to a second end of the load;

[0052] The fifteenth resistor R32 and the seventh capacitor C20 are respectively connected between the first end of the common mode inductor L4 and the second end of the common mode inductor L4, the first end of the eighth capacitor C7 is connected to the first end of the common mode inductor L4, and the second end of the eighth capacitor C7 is connected to the second end of the common mode inductor L4 via the ninth capacitor C6;

[0053] The tenth capacitor C27 and the first varistor MOV3 are respectively connected between the third end of the common-mode inductor L4 and the fourth end of the common-mode inductor L4; the first end of the eleventh capacitor C17 is connected to the third end of the common-mode inductor L4, and the second end of the eleventh capacitor C17 is connected to the fourth end of the common-mode inductor L4 via the twelfth capacitor C33; the first end of the second varistor MOV2 is connected to the third end of the common-mode inductor L4, the second end of the second varistor MOV2 is connected to the first end of the third varistor MOV5, and the second end of the third varistor MOV5 is connected to the fourth end of the common-mode inductor L4; one end of the gas discharge tube GT2 is connected between the second end of the second varistor MOV2 and the first end of the third varistor MOV5, and the other end of the gas discharge tube GT2 is grounded.

[0054] Specifically, the seventh capacitor C20, the eighth capacitor C7, the ninth capacitor C6, the tenth capacitor C27, the eleventh capacitor C17, and the twelfth capacitor C33 are all capacitive loads of alternating current. When the mains is disconnected, residual voltage exists at both ends of these capacitive loads. The first varistor MOV3, the second varistor MOV2, and the third varistor MOV5 are used to discharge the capacitive loads. The gas discharge tube GT2 is used for overvoltage protection.

[0055] In one embodiment, the inverter 212 power supply circuit 200 includes a tank circuit 240;

[0056] The first output end of the mains power supply circuit 100 is connected to the first end of the energy storage circuit 240 via the capacitive load circuit 220, the second filter circuit 216, and the inverter 212; the second output end of the mains power supply circuit 100 is connected to the second end of the energy storage circuit 240 via the capacitive load circuit 220, the second filter circuit 216, and the inverter 212;

[0057] When the AC power supply circuit 100 is supplying power, the AC power supply circuit 100 outputs the AC voltage to charge the energy storage circuit 240; when the AC power supply circuit 100 is switched to the inverter 212 to supply the circuit 200, the first end of the energy storage circuit 240 serves as the positive electrode of the DC power supply, and the second end of the energy storage circuit 240 serves as the negative electrode of the DC power supply.

[0058] The energy storage circuit 240 may be an electrolytic capacitor.

[0059] Specifically, when the mains power supply circuit 100 supplies power to the load, the AC power output by the mains power supply circuit 100 can charge the energy storage circuit 240. When the mains power supply circuit 100 is disconnected, the energy storage circuit 240 can act as a DC power supply, supply the power supply circuit 200 via the inverter 212, output an inverter voltage, and supply power to the load.

[0060] In one embodiment, the energy storage circuit 240 includes a fifth capacitor E1 and a sixth capacitor E2 ; the fifth capacitor E1 and the sixth capacitor E2 are connected in parallel between the first terminal of the inverter 212 and the second terminal of the inverter 212 .

[0061] Specifically, the fifth capacitor E1 and the sixth capacitor E2 are both polarized electrolytic capacitors, and when the mains power supply circuit 100 supplies power to the load, the fifth capacitor E1 and the sixth capacitor E2 are in a charging state, and when the mains power supply circuit 100 is disconnected, the fifth capacitor E1 and the sixth capacitor E2 are in a discharging state.

[0062] In one embodiment, based on the load power supply circuit of the mains and the inverter 212, the voltage conversion circuit 300 includes a transformer CT2, a third relay RL2 and a fourth filter circuit 310, the transformer CT2 includes a first primary winding, a second primary winding and a secondary winding; the third relay RL2 includes a third control coil, a sixth contact and a seventh contact; the fourth filter circuit 310 includes a sixteenth capacitor C25, a seventeenth capacitor C18 and an eighteenth capacitor C38;

[0063] The opposite-name end of the first primary winding is connected to the first output end of the mains power supply circuit 100 and the first output end of the inverter circuit 210, the same-name end of the first primary winding is connected to the sixth contact, and the seventh contact is connected to the first end of the load; the opposite-name end of the second primary winding is connected to the first output end of the mains power supply circuit 100, and the same-name end of the second primary winding is connected to the sixth contact; the same-name end of the secondary winding is grounded; the first end of the third control coil is connected to the DC power supply, and the second end of the third control coil is grounded;

[0064] The first end of the sixteenth capacitor C25 is connected to the seventh contact, and the second end of the sixteenth capacitor C25 is connected to the first end of the load; the first end of the seventeenth capacitor C18 is connected to the seventh contact, the second end of the seventeenth capacitor C18 is connected to the first end of the eighteenth capacitor C38 and the ground terminal, and the second end of the eighteenth capacitor C38 is connected to the second end of the load.

[0065] The transformer CT2 is used to step up or down the voltage, and the fourth filter circuit 310 is used to filter the voltage across the load. The third relay RL2 is used to control the on or off of the AC power supply circuit 100 and the inverter 212 power supply circuit 200 to supply power to the load.

[0066] Specifically, a first end of the third control coil is connected to a DC power supply, a second end of the third control coil is grounded, current always flows through the third control coil, and the sixth contact and the seventh contact are always connected.

[0067] See also Figure 2 , the following will combine Figure 2 The working process of this application is described in detail:

[0068] The alternating current is connected to the load power supply circuit through the first input terminal of the mains power supply circuit 100 and the second input terminal of the mains power supply circuit 100, wherein IN.L represents the live wire and IN.N represents the neutral wire.

[0069] The first control port of the single-chip microcomputer outputs a high level, controls the first switch circuit to conduct, thereby energizing the first control coil and connecting the first contact to the second contact; the second control port of the single-chip microcomputer outputs a high level, controls the second switch circuit to conduct, thereby energizing the second control coil and connecting the third contact to the fourth contact. The AC 380V is stepped down to 220V by transformer CT2 to supply power to the load.

[0070] The single-chip microcomputer detects an abnormality in the alternating current, and the first control port of the single-chip microcomputer outputs a low level, controlling the first switch circuit to be disconnected, so that no current flows through the first control coil, and the first contact is disconnected from the second contact; the second control port of the single-chip microcomputer outputs a high level, controlling the second switch circuit to be disconnected, so that no current flows through the second control coil, the third contact is disconnected from the fourth contact, and the third contact is connected to the fifth contact. The AC power supply circuit 100 is disconnected, and the inverter 212 power supply circuit 200 starts to supply power to the load. When the AC power supply circuit 100 is disconnected, the presence of the capacitive load will cause residual voltage to exist at both ends of the capacitive load. The control circuit 230 collects the voltage of the first end of the capacitive load circuit 220, and outputs a control signal to drive the inverter circuit 210 to output an inverter voltage based on the voltage of the first end of the capacitive load circuit 220, so that the inverter voltage output by the inverter circuit 210 is basically consistent with the voltage of the first end of the capacitive load circuit 220, thereby avoiding large surge current in the capacitive load circuit 220, damaging the inverter circuit 210 and the load, and improving the safety of the load power supply circuit.

[0071] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0072] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A load power supply circuit based on mains power and inverter, characterized in that: Including a mains power supply circuit and an inverter power supply circuit; The first input end of the mains power supply circuit is connected to the live wire of the alternating current, the second input end of the mains power supply circuit is connected to the neutral wire of the alternating current, the first output end of the mains power supply circuit is connected to the first end of the load, and the second output end of the mains power supply circuit is connected to the second end of the load; The inverter power supply circuit comprises an inverter circuit, a capacitive load circuit and a control circuit; a first input terminal of the inverter circuit is connected to the positive electrode of a DC power supply, a second input terminal of the inverter circuit is connected to the negative electrode of the DC power supply, a signal driving terminal of the inverter circuit is connected to a control signal output terminal of the control circuit, a first output terminal of the inverter circuit is connected to a first terminal of the capacitive load circuit, and a second output terminal of the inverter circuit is connected to a second terminal of the capacitive load circuit; a signal sampling terminal of the control circuit is connected to a first terminal of the capacitive load circuit; a third terminal of the capacitive load circuit is connected to a first terminal of the load, and a fourth terminal of the capacitive load circuit is connected to a second terminal of the load; When the AC power supply circuit switches to the inverter power supply circuit, the control circuit samples the voltage of the first end of the capacitive load circuit through the signal sampling end, and outputs a control signal through the control signal output end to drive the inverter circuit to output an inverter voltage to power the load.

2. The load power supply circuit based on mains power and inverter according to claim 1, characterized in that: The inverter circuit includes an inverter, a first filter circuit and a second filter circuit; The first end of the inverter is the first input end of the inverter circuit, which is used to be connected to the positive electrode of the DC power supply; the second end of the inverter is the second input end of the inverter circuit, which is used to be connected to the negative electrode of the DC power supply; the third end of the inverter is the signal driving end of the inverter circuit, which is used to be connected to the control signal output end of the control circuit; the fourth end of the inverter is connected to the first end of the second filter circuit, and the fifth end of the inverter is the second output end of the inverter circuit, which is used to be connected to the second end of the capacitive load circuit; the second end of the second filter circuit is connected to the first end of the capacitive load circuit; the first end of the first filter circuit is connected to the positive electrode of the DC power supply, and the second end of the first filter circuit is connected to the negative electrode of the DC power supply.

3. The load power supply circuit based on mains power and inverter according to claim 2, characterized in that: The control signal output terminal of the control circuit includes a first control signal output terminal, a second control signal output terminal, a third control signal output terminal and a fourth control signal output terminal; the third terminal of the inverter includes a first signal driving terminal, a second signal driving terminal, a third signal driving terminal and a fourth signal driving terminal; The inverter includes a first triode, a second triode, a third triode, a fourth triode, a first diode, a second diode, a third diode, a fourth diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor and a twelfth resistor; The collector of the first triode is connected to the positive electrode of the DC power supply, the base of the first triode is connected to the first end of the second resistor through the first resistor, the second end of the second resistor is the first signal driving end, which is used to be connected to the first control signal output end, the emitter of the first triode is connected to the collector of the second triode, the first diode is connected in parallel to the two ends of the second resistor, and the third resistor is connected between the base of the first triode and the emitter of the first triode; The base of the second triode is connected to the first end of the fifth resistor through the fourth resistor, the second end of the fifth resistor is the second signal driving end, which is used to be connected to the second control signal output end, the emitter of the second triode is connected to the negative electrode of the DC power supply, the second diode is connected in parallel to the two ends of the fifth resistor, and the sixth resistor is connected between the base of the second triode and the emitter of the second triode; The collector of the third triode is connected to the positive electrode of the DC power supply, the base of the third triode is connected to the first end of the eighth resistor through the seventh resistor, the second end of the eighth resistor is the third signal driving end, which is used to be connected to the third control signal output end, the emitter of the third triode is connected to the collector of the fourth triode and the first end of the capacitive load circuit, the third diode is connected in parallel to the two ends of the eighth resistor, and the ninth resistor is connected between the base of the third triode and the emitter of the third triode; The base of the fourth transistor is connected to the first end of the eleventh resistor through the tenth resistor, the second end of the eleventh resistor is the fourth signal driving end, which is used to be connected to the fourth control signal output end, the emitter of the fourth transistor is connected to the negative electrode of the DC power supply, the fourth diode is connected in parallel at both ends of the eleventh resistor, and the twelfth resistor is connected between the base of the fourth transistor and the emitter of the fourth transistor.

4. The load power supply circuit based on mains power and inverter according to claim 2, characterized in that: The second filtering circuit includes a current sensor, a first inductor, a second inductor, a first capacitor and a second capacitor; The first end of the current sensor is the first end of the second filter circuit, which is used to be connected to the fourth end of the inverter. The second end of the current sensor is connected to the first end of the first inductor. The first end of the first inductor is the second end of the second filter circuit, which is used to be connected to the first end of the capacitive load circuit. The third end of the current sensor is grounded via the first capacitor. The fourth end of the current sensor and the fifth end of the current sensor are respectively connected to the first signal sampling chip. The sixth end of the current sensor is grounded. One end of the second capacitor is connected to the third end of the current sensor and a DC power supply, and the other end of the second capacitor is grounded. The first end of the second inductor is connected to the fourth end of the inverter, and the second end of the second inductor is connected to the first end of the capacitive load circuit.

5. The load power supply circuit based on mains power and inverter according to claim 2, characterized in that: The first filtering circuit includes a third capacitor, a fourth capacitor, a thirteenth resistor and a fourteenth resistor; The third capacitor, the fourth capacitor, the thirteenth resistor, and the fourteenth resistor are all connected in parallel between the first end of the inverter and the second end of the inverter.

6. The load power supply circuit based on mains power and inverter according to claim 2, characterized in that: The capacitive load circuit includes a fifteenth resistor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a tenth capacitor, an eleventh capacitor, a twelfth capacitor, a common mode inductor, a first varistor, a second varistor, a third varistor and a gas discharge tube; The first end of the common mode inductor is connected to the second end of the second filter circuit, the second end of the common mode inductor is connected to the fifth end of the inverter, the third end of the common mode inductor is connected to the first end of the load, and the fourth end of the common mode inductor is connected to the second end of the load; The fifteenth resistor and the seventh capacitor are respectively connected between the first end of the common mode inductor and the second end of the common mode inductor, the first end of the eighth capacitor is connected to the first end of the common mode inductor, and the second end of the eighth capacitor is connected to the second end of the common mode inductor via the ninth capacitor; The tenth capacitor and the first varistor are respectively connected between the third end of the common-mode inductor and the fourth end of the common-mode inductor; the first end of the eleventh capacitor is connected to the third end of the common-mode inductor, and the second end of the eleventh capacitor is connected to the fourth end of the common-mode inductor via the twelfth capacitor; the first end of the second varistor is connected to the third end of the common-mode inductor, the second end of the second varistor is connected to the first end of the third varistor, and the second end of the third varistor is connected to the fourth end of the common-mode inductor; one end of the gas discharge tube is connected between the second end of the second varistor and the first end of the third varistor, and the other end of the gas discharge tube is grounded.

7. The load power supply circuit based on mains power and inverter according to claim 2, characterized in that: The inverter power supply circuit includes an energy storage circuit; The first output end of the mains power supply circuit is connected to the first end of the energy storage circuit via the capacitive load circuit, the second filter circuit, and the inverter; the second output end of the mains power supply circuit is connected to the second end of the energy storage circuit via the capacitive load circuit, the second filter circuit, and the inverter; When the AC power supply circuit is supplying power, the AC power supply circuit outputs a AC voltage to charge the energy storage circuit; when the AC power supply circuit is switched to the inverter power supply circuit, the first end of the energy storage circuit serves as the positive electrode of the DC power supply, and the second end of the energy storage circuit serves as the negative electrode of the DC power supply.

8. The load power supply circuit based on mains power and inverter according to claim 7, characterized in that: The energy storage circuit includes a fifth capacitor and a sixth capacitor; The fifth capacitor and the sixth capacitor are both connected in parallel between the first end of the inverter and the second end of the inverter.

9. The load power supply circuit based on mains power and inverter according to any one of claims 1 to 8, characterized in that: The mains power supply circuit includes a third filter circuit, a first relay and a second relay; the first relay includes a first control coil, a first contact and a second contact, and the second relay includes a second control coil, a third contact, a fourth contact and a fifth contact; The first end of the third filter circuit is connected to the live wire of the alternating current, the second end of the third filter circuit is connected to the neutral wire of the alternating current, the third end of the third filter circuit is connected to the first contact, the second contact is connected to the first end of the load, the fourth end of the third filter circuit is connected to the third contact, the fourth contact is connected to the second end of the load, and the fifth contact is grounded; the first end of the first control coil is connected to the DC power supply, the second end of the first control coil is connected to the first end of the first switch circuit, the second end of the first switch circuit is connected to the first control port of the single-chip microcomputer, and the third end of the first switch circuit is grounded; the first end of the second control coil is connected to the DC power supply, the second end of the second control coil is connected to the first end of the second switch circuit, the second end of the second switch circuit is connected to the second control port of the single-chip microcomputer, and the third end of the second switch circuit is grounded.

10. The load power supply circuit based on mains power and inverter according to claim 9, characterized in that: The third filtering circuit includes a thirteenth capacitor, a fourteenth capacitor and a fifteenth capacitor. The first end of the thirteenth capacitor is connected to the live wire of the alternating current, the second end of the thirteenth capacitor is connected to the neutral wire of the alternating current, the first end of the fourteenth capacitor is connected to the live wire of the alternating current, the second end of the fourteenth capacitor is connected to the first end of the fifteenth capacitor and the ground end, and the second end of the fifteenth capacitor is connected to the neutral wire of the alternating current.

11. The load power supply circuit based on mains power and inverter according to any one of claims 1 to 8, characterized in that: Also includes a voltage conversion circuit; The voltage conversion circuit includes a transformer, a third relay and a fourth filter circuit, the transformer includes a first primary winding, a second primary winding and a secondary winding; the third relay includes a third control coil, a sixth contact and a seventh contact; the fourth filter circuit includes a sixteenth capacitor, a seventeenth capacitor and an eighteenth capacitor; The opposite-name end of the first primary winding is connected to the first output end of the mains power supply circuit and the first output end of the inverter circuit, the same-name end of the first primary winding is connected to the sixth contact, and the seventh contact is connected to the first end of the load; the opposite-name end of the second primary winding is connected to the first output end of the mains power supply circuit, and the same-name end of the second primary winding is connected to the sixth contact; the same-name end of the secondary winding is grounded; the first end of the third control coil is connected to a DC power supply, and the second end of the third control coil is grounded; The first end of the sixteenth capacitor is connected to the seventh contact, and the second end of the sixteenth capacitor is connected to the first end of the load; the first end of the seventeenth capacitor is connected to the seventh contact, the second end of the seventeenth capacitor is connected to the first end of the eighteenth capacitor and the ground terminal, and the second end of the eighteenth capacitor is connected to the second end of the load.

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