A fully isolated power supply

Abstract

The present invention discloses a fully isolated power supply, comprising: a transformer, the transformer is connected with a filtering unit, the filtering unit outputs electric energy to a rectifying unit; a control unit, the control unit is electrically connected to the rectifying unit; an isolation unit, the isolation unit is electrically connected to the control unit; a first DC filtering unit, the first DC filtering unit is electrically connected to the isolation unit, the control unit and the filtering unit, the first DC filtering unit outputs the electric energy of the rectifying unit; a second DC filtering unit, the second DC filtering unit is electrically connected to the isolation unit, the second DC filtering unit outputs isolated DC power to a load; the power supply can isolate various interferences at the AC end of the mains power, and then output clean DC power.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply equipment, and in particular to a fully isolated power supply. Background Art

[0002] In some laboratories or high-demand occasions, for the safety of experimenters or to obtain input with less noise, the input power is generally isolated from the city point by an industrial frequency transformer. A noise reduction circuit composed of inductors and capacitors can also be used to obtain a cleaner input source.

[0003] Each module is powered and works independently without interference. In the field of audio use, it is very necessary to isolate and reduce the noise of the mains input source. Only by obtaining a cleaner input source can low, medium and high frequencies with less noise interference be output.

[0004] Existing power supplies or converters generally add noise reduction circuits at least at the transformer output and the rectifier unit output, reducing some noise through inductance and capacitance, but at the same time increasing the power supply impedance or the capacitive load or inductive load at both ends of the device or in series with the output, which may have an adverse effect on the output sound. Since the rectifier unit and the isolated output are not further isolated, the mains power can still directly affect the isolated DC output through the transformer and the rectifier unit. At this time, the noise interference of the isolated DC output is still relatively large, and the structure of the existing isolated power supply or combined power supply is too complicated, the power consumption is greater in use, the production cost is higher, and the service life is not long.

[0005] Therefore, there is an urgent need for a fully isolated power supply that can solve one or more of the above problems. Summary of the invention

[0006] In order to solve one or more problems existing in the prior art, the present invention provides a fully isolated power supply. The technical solution adopted by the present invention to solve the above problems is: a fully isolated power supply, which includes: a transformer, the transformer is connected to a filter unit, the filter unit outputs to a rectifier unit, and the rectifier unit rectifies the filtered alternating current and outputs direct current;

[0007] A control unit, the control unit is electrically connected to the rectifier unit and receives an on / off signal of the rectifier unit;

[0008] a first DC filter unit, wherein the first DC filter unit is provided with a first capacitor unit, the first DC filter unit is electrically connected to the rectifying unit, and the DC power output by the rectifying unit is output via the first DC filter unit;

[0009] an isolation unit, the isolation unit being electrically connected to the control unit, the first DC filter unit outputting DC power to the isolation unit, and the isolation unit playing a role of isolating the output;

[0010] a second DC filter unit, wherein a second capacitor unit is disposed in the second DC filter unit, the second DC filter unit is electrically connected to the isolation unit, the isolation unit outputs electric energy to the second DC filter unit, and the second DC filter unit outputs isolated DC power to the load;

[0011] The city power is filtered by the filter unit and then output to the rectifier unit, the rectifier unit outputs direct current to the first direct current filter, the control unit receives the on / off signal of the rectifier unit, the isolation unit receives the control signal output by the control unit to turn on or off, the isolation unit outputs electric energy to the second direct current filter unit, and the second direct current filter unit outputs electric energy to the load or the secondary;

[0012] Under the control of the control unit, when the rectifying unit is turned off, the isolating unit is turned on and supplies power to the second DC filter unit, and the power of the isolating unit is provided by the first capacitor unit in the first DC filter unit;

[0013] Under the control of the control circuit, the isolation unit is turned off when the rectifying unit is turned on, and the electric energy output by the second DC filtering unit is provided by the second capacitor unit.

[0014] Furthermore, the first capacitor unit and the second capacitor unit are capacitors.

[0015] Furthermore, a switch tube is provided in the isolation unit, and a control signal of the switch tube is sent by the control unit;

[0016] The isolation unit is provided with any one or more of an isolation optocoupler and an isolation relay. The control signal of the control unit is isolated by the isolation optocoupler or the isolation relay. The isolation optocoupler or the isolation relay outputs the isolated control signal to the switch tube. After the switch tube is turned on, the first capacitor unit supplies power to the second DC filter unit.

[0017] Furthermore, the filtering unit is an EMC filtering network or an EMI filtering network.

[0018] Furthermore, the control unit is any one or a combination of an MCU and an auxiliary circuit;

[0019] The auxiliary circuit is a rectifier circuit composed of diodes. The auxiliary circuit is electrically connected to the rectifier unit and receives an on / off signal of the rectifier unit.

[0020] Furthermore, the auxiliary circuit is provided with a first auxiliary circuit and a second auxiliary circuit, the first auxiliary circuit is a bridge rectifier circuit composed of a diode and a capacitor, and the second auxiliary circuit is a full-wave rectifier circuit composed of a diode;

[0021] The isolation unit is provided with a first electrode output unit and a second electrode output unit, and the first electrode output unit and the second electrode output unit cooperate to provide direct current to the second direct current filter unit;

[0022] Under the joint action of the first auxiliary circuit and the second auxiliary circuit, the first electrode output unit and the second electrode output unit are both in an on or off state, and the switching between the on and off states is performed continuously and smoothly alternately.

[0023] Furthermore, a phase shift circuit and a time constant circuit are provided in the first auxiliary circuit, and the phase shift circuit and the time constant circuit make the conduction angle of the first auxiliary circuit inconsistent with the conduction angle of the second auxiliary circuit, so that the rectifier unit end and the second DC filter unit end are floating at both ends of the isolation unit.

[0024] Furthermore, the phase shift circuit is composed of a plurality of capacitors, and the time constant circuit is composed of a capacitor and a resistor.

[0025] The beneficial effect achieved by the present invention is that the present invention realizes the isolation of the main power bus input end from the rectified power output end by connecting the control unit, the filter unit, the isolation unit, the first DC filter unit, the second DC filter unit and others through ingenious structures and methods and controlling the output, and is equivalent to physical isolation, so that the power end can achieve a good isolation power supply effect, reducing various interferences from the AC mains input end and the impact of various high and low frequency pulses. The above greatly improves the practical value of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of a fully isolated power supply of the present invention is shown in FIG. Figure 1 ;

[0027] Figure 2 A schematic diagram of a fully isolated power supply of the present invention is shown in FIG. Figure 2 ;

[0028] Figure 3 The principle of a fully isolated power supply of the present invention is Figure 1 ;

[0029] Figure 4 The principle of a fully isolated power supply of the present invention is Figure 2 ;

[0030] Figure 5 This is a power input waveform diagram of a fully isolated power supply of the present invention;

[0031] Figure 6The figure is a waveform diagram of the power-using end output of a fully isolated power supply of the present invention.

[0032] [Reference Signs]

[0033] S01···Transformer

[0034] S02···Filter unit

[0035] S03···Rectifier unit

[0036] S04···Control Unit

[0037] S041···First auxiliary circuit

[0038] S042···Second auxiliary circuit

[0039] S05···Isolation Unit

[0040] S051···First electrode output unit

[0041] S052···Second electrode output unit

[0042] S06···First DC filter unit

[0043] S07···Second DC filtering unit. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned objects, features and advantages of the present invention more understandable, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from this description, and those skilled in the art can make similar improvements without violating the connotation of the present invention, so the present invention is not limited by the specific embodiments disclosed below.

[0045] like Figure 1-Figure 4 As shown, the present invention discloses a fully isolated power supply, which includes: a transformer S01, the transformer S01 is connected to a filter unit S02, the filter unit S02 outputs to a rectifier unit S03, the rectifier unit S03 is generally a rectifier bridge, and the rectifier unit S03 rectifies the filtered alternating current and outputs direct current;

[0046] A control unit S04, wherein the control unit S04 is electrically connected to the rectifying unit S03 and receives an on / off signal of the rectifying unit S03;

[0047] A first DC filter unit S06, wherein the first DC filter unit S06 is provided with a first capacitor unit, the first DC filter unit S06 is electrically connected to the rectifier unit S03, and the DC power output by the rectifier unit S03 is output via the first DC filter unit S06;

[0048] An isolation unit S05, wherein the isolation unit S05 is electrically connected to the control unit S04, and the first DC filter unit S06 outputs DC power to the isolation unit S05, and the isolation unit S05 plays a role of isolating the output;

[0049] A second DC filter unit S07, wherein a second capacitor unit is disposed in the second DC filter unit S07, the second DC filter unit S07 is electrically connected to the isolation unit S05, the isolation unit S05 outputs electric energy to the second DC filter unit S07, and the second DC filter unit S07 outputs isolated DC power to the load;

[0050] The mains electricity is filtered by the filter unit S02 and then output to the rectifier unit S03. The rectifier unit S03 outputs direct current to the first direct current filter S06. The control unit S04 receives the on / off signal of the rectifier unit S03. The isolation unit S05 receives the control signal output by the control unit S04 to turn on or off. The isolation unit S05 outputs electric energy to the second direct current filter unit S07. The second direct current filter unit S07 outputs electric energy to the load or the secondary.

[0051] Under the control of the control unit S04, when the rectifying unit S03 is turned off, the isolating unit S05 is turned on and supplies power to the second DC filtering unit S07. The power of the isolating unit S05 is provided by the first capacitor unit in the first DC filtering unit S06.

[0052] Under the control of the control circuit S04, when the rectifying unit S03 is turned on, the isolating unit S05 is turned off, and the electric energy output by the second DC filtering unit S07 is provided by the second capacitor unit.

[0053] It should be noted that the rectifier unit S03 generally refers to a rectifier bridge or an output module with a rectifier function, thereby providing a DC input to subsequent units. The control unit S04 is generally a circuit or MCU that receives and outputs a control signal. Generally speaking, the first capacitor unit and the second capacitor unit are filter capacitors. The first capacitor unit is charged when the rectifier unit S03 (rectifier bridge) is turned on. When the control unit S04 detects that the rectifier unit S03 (rectifier bridge) is turned on, it sends a control signal to the isolation unit S05, and the isolation unit S05 disconnects the connection with the first DC filter unit S06. At this time, the second capacitor unit supplies energy to the second DC filter unit S07; when the first capacitor unit is turned off in the sorting unit S03 (rectifier bridge), the control unit S04 detects that the rectifier unit S03 (rectifier bridge) is turned off, and sends a control signal to the isolation unit S05. The isolation unit S05 opens the connection with the first DC filter unit S06. Since the sorting unit S03 (sorting bridge) is turned off, the first capacitor unit supplies power to the second DC filter unit S07 and the second capacitor unit.

[0054] In the above process, the isolation unit S05 mainly plays the role of equivalent physical isolation between the rectifier unit S03 and the second DC filter unit S07. The isolation unit S05 also plays the role of isolating the start and stop instructions output by the control unit S04 to the first DC filter unit S06 in the circuit to avoid the output control instructions from interfering with the output waveform, etc. Therefore, the control signal between the isolation unit S05 and the control unit S04 is generally a non-electrical signal, such as a light signal, a sound signal or a vibration signal.

[0055] Specifically, Figure 1 , Figure 3 , Figure 4 As shown, a switch tube is provided in the isolation unit S05, and the control signal of the switch tube is issued by the control unit S04; any one or more of an isolation optocoupler and an isolation relay are provided in the isolation unit S05, and the control signal of the control unit S04 is isolated by the isolation optocoupler or the isolation relay, and the isolation optocoupler or the isolation relay outputs the isolated control signal to the switch tube, and after the switch tube is turned on, the first capacitor unit supplies power to the second DC filter unit S07. The control signal output by the control unit S04 is isolated by the isolation optocoupler in the isolation unit S05, converted into an optical signal, then converted into an electrical signal, and then output to the switch tube, so as to avoid the current of the conduction signal being directly added to the circuit, causing interference to the output waveform and other effects. Generally speaking, the isolation unit S05 can be equivalent to a photoelectric isolation circuit.

[0056] Specifically, Figure 3 , Figure 4 As shown, the filtering unit S02 is an EMC filtering network or an EMI filtering network, and its function is to remove noise from the input AC power and the output DC power.

[0057] It should be noted that the control unit S04 is any one or a combination of an MCU and an auxiliary circuit; the auxiliary circuit is a rectifier circuit composed of diodes, and the auxiliary circuit is electrically connected to the rectifier unit S03 and receives the start and stop signal of the rectifier unit S03.

[0058] Specifically, Figure 2-Figure 4 As shown, the auxiliary circuit includes a first auxiliary circuit S041 and a second auxiliary circuit S042, the first auxiliary circuit S041 is a bridge rectifier circuit composed of a diode and a capacitor, and the second auxiliary circuit S042 is a full-wave rectifier circuit composed of a diode;

[0059] The isolation unit S05 is provided with a first electrode output unit S051 and a second electrode output unit S052, and the first electrode output unit S051 and the second electrode output unit S052 cooperate to provide direct current to the second direct current filter unit S07;

[0060] Under the joint action of the first auxiliary circuit S041 and the second auxiliary circuit S041, the first electrode output unit S051 and the second electrode output unit S052 are both in an on or off state, and the switching between the on and off states is continuous and smoothly alternating.

[0061] Furthermore, a phase shift circuit and a time constant circuit are provided in the first auxiliary circuit S041, and the phase shift circuit and the time constant circuit make the conduction angle of the first auxiliary circuit S041 inconsistent with the conduction angle of the second auxiliary circuit S042, so that the rectifier unit S03 (rectifier bridge) end and the second DC filter unit S07 end are floating at both ends of the isolation unit S05. Generally speaking, the phase shift circuit is composed of multiple capacitors, and the time constant circuit is composed of capacitors and resistors.

[0062] Figure 4This is a practical application principle diagram of the present invention. It should be noted that the EMC network composed of inductor L1, inductor L2, capacitor C1, and capacitor C2 is connected to the output end of transformer TF1, diode D5, diode D6, diode D7, and diode D8 constitute the rectifier bridge of the main power supply, capacitor C6 is the filter capacitor (first capacitor unit) in the first DC filter unit S06 and acts on the rectifier bridge, diode D1, diode D2, diode D3, diode D4, capacitor C3, and capacitor C4 constitute the first auxiliary circuit S041, wherein capacitor C3 and capacitor C4 are used as power coupling capacitors and phase shifting capacitors, capacitor C5 is the filter capacitor of the first auxiliary circuit S041, resistor R1, resistor R2 , and resistor R3 are both current limiting resistors. The switch tube Q1 is the positive switch tube of the main power supply, that is, the switch tube in the first electrode output unit S051. The switch tube Q2 is the negative switch tube of the main power supply, that is, the switch tube in the second electrode output unit S052. The diode D11 and the diode D12 are gate voltage limiting protection diodes of the switch tube Q1 and the switch tube Q2. The diode D9 and the diode D10 form the second auxiliary circuit S042 and realize full-wave rectification. The optocoupler U1 and the optocoupler U2 are isolation optocouplers for gate control of the switch tube Q1 and the switch tube Q2. The inductor L3, the inductor L4, and the capacitor C7 are the main filter network at the isolation end of the main power supply (rectifier bridge), that is, the second DC filter unit S07.

[0063] In actual use, the AC power from the secondary of the transformer first passes through the EMC network to filter out various high-frequency and high-interference from the AC power supply end, and at the same time isolates various high-frequency interference from the power consumption end to prevent the power consumption end from outputting various high-frequency interference to the AC power end. After the AC power with various high-frequency interferences and pulses is initially filtered out, it is rectified by the rectifier bridge and filtered by the filter capacitor C6, and then the main DC power is output to the drain of the Q1 and Q2 switch tubes. Under the joint action of the first auxiliary circuit S041 and the second auxiliary circuit S042, the Q1 and Q2 switch tubes are both turned on or off, and the switching between the on and off states is continuous and smoothly alternating. Since the Q1 and Q2 switch tubes are deeply affected by the first auxiliary circuit S041 and the second auxiliary circuit S042, if for some reason there is a pulse at the input end of the rectifier diode, this pulse outputs a higher DC power after passing through the rectifier filter circuit. At the same time, this pulse will be processed by the first auxiliary circuit S041 and the second auxiliary circuit S042. The processed output will increase the conduction angle of the Q1 and Q2 switch tubes, causing the Q1 and Q2 switch tubes to output more DC power to the main filter network at the isolation end, thereby absorbing the energy of the pulse and converting it into DC power.

[0064] And because the phase shift circuit composed of C3 and C4 on the first auxiliary circuit S041, the time constant circuit composed of R1 and C5, and the conduction angles of the Q1 and Q2 switches are inconsistent, the main power supply end and the isolated power supply end are floating at both ends of the Q1 and Q2 switches. Through the above combined effects, the isolated power supply end obtains a better isolated power supply effect and is free from various interferences from the AC mains input end and the impact of various high and low frequency pulses.

[0065] like Figure 5 , Figure 6 As shown, Figure 5 This is the waveform of the power supply input. Figure 6 The waveform diagram of the isolation end output of the present invention is shown in Figure 2. By comparing the two diagrams, it can be seen that the present invention has a better anti-interference effect after isolating the mains power. It should be pointed out that the present invention can still achieve a good isolation effect in a wide frequency band.

[0066] In summary, the present invention achieves isolation of the main power bus input end from the rectified power output end by connecting the control unit S04, the filter unit S02, the isolation unit S05, the first DC unit S06, the second DC filter unit S07 and others through ingenious structures and methods and controlling the output, and is equivalent to physical isolation, so that the power end can achieve a good isolation power supply effect, reducing various interferences from the AC mains input end and the impact of various high and low frequency pulses. The above greatly improves the practical value of the present invention.

[0067] The above-described embodiments only express one or more implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as a limitation on the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the attached claims.

Claims

1. A fully isolated power supply, characterized in that: The invention comprises: a transformer, the transformer is connected to a filter unit, the filter unit outputs to a rectifier unit, and the rectifier unit rectifies the filtered alternating current and outputs direct current; A control unit, the control unit is electrically connected to the rectifier unit and receives an on / off signal of the rectifier unit; a first DC filter unit, wherein the first DC filter unit is provided with a first capacitor unit, the first DC filter unit is electrically connected to the rectification unit, and the DC power output by the rectification unit is output via the first DC filter unit; an isolation unit, the isolation unit being electrically connected to the control unit, the first DC filter unit outputting DC power to the isolation unit, and the isolation unit playing a role of isolating the output; a second DC filter unit, wherein a second capacitor unit is disposed in the second DC filter unit, the second DC filter unit is electrically connected to the isolation unit, the isolation unit outputs electric energy to the second DC filter unit, and the second DC filter unit outputs isolated DC power to the load; The city power is filtered by the filter unit and then output to the rectifier unit, the rectifier unit outputs direct current to the first direct current filter unit, the control unit receives the on / off signal of the rectifier unit, the isolation unit receives the control signal output by the control unit to turn on or off, the isolation unit outputs electric energy to the second direct current filter unit, and the second direct current filter unit outputs electric energy to the load or the secondary; Under the control of the control unit, when the rectifying unit is turned off, the isolating unit is turned on and supplies power to the second DC filter unit, and the power of the isolating unit is provided by the first capacitor unit in the first DC filter unit; Under the control of the control circuit, the isolation unit is turned off when the rectifying unit is turned on, and the electric energy output by the second DC filtering unit is provided by the second capacitor unit.

2. A fully isolated power supply according to claim 1, characterized in that: The first capacitor unit and the second capacitor unit are capacitors.

3. A fully isolated power supply according to claim 1, characterized in that: A switch tube is provided in the isolation unit, and a control signal of the switch tube is sent by the control unit; The isolation unit is provided with any one or more of an isolation optocoupler and an isolation relay. The control signal of the control unit is isolated by the isolation optocoupler or the isolation relay. The isolation optocoupler or the isolation relay outputs the isolated control signal to the switch tube. After the switch tube is turned on, the first capacitor unit supplies power to the second DC filter unit.

4. A fully isolated power supply according to claim 1, characterized in that: The filtering unit is an EMC filtering network or an EMI filtering network.

5. A fully isolated power supply according to claim 1, characterized in that: The control unit is any one or a combination of an MCU and an auxiliary circuit; The auxiliary circuit is a rectifier circuit composed of diodes. The auxiliary circuit is electrically connected to the rectifier unit and receives an on / off signal of the rectifier unit.

6. A fully isolated power supply according to claim 5, characterized in that: The auxiliary circuit is provided with a first auxiliary circuit and a second auxiliary circuit, the first auxiliary circuit is a bridge rectifier circuit composed of a diode and a capacitor, and the second auxiliary circuit is a full-wave rectifier circuit composed of a diode; The isolation unit is provided with a first electrode output unit and a second electrode output unit, and the first electrode output unit and the second electrode output unit cooperate to provide direct current to the second direct current filter unit; Under the joint action of the first auxiliary circuit and the second auxiliary circuit, the first electrode output unit and the second electrode output unit are both in an on or off state, and the switching between the on and off states is performed continuously and smoothly alternately.

7. A fully isolated power supply according to claim 6, characterized in that: A phase shift circuit and a time constant circuit are provided in the first auxiliary circuit. The phase shift circuit and the time constant circuit make the conduction angle of the first auxiliary circuit inconsistent with the conduction angle of the second auxiliary circuit, so that the rectifier unit end and the second DC filter unit end are floating at both ends of the isolation unit.

8. A fully isolated power supply according to claim 7, characterized in that: The phase shift circuit is composed of a plurality of capacitors, and the time constant circuit is composed of a capacitor and a resistor.

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