Three-phase phase sequence detection circuit with isolation

Abstract

The utility model discloses a three-phase phase sequence detection circuit with isolation, and belongs to the technical field of phase sequence detection. According to the circuit, the first input end of a first optocoupler is connected with an A-phase input end, the first input end of a second optocoupler is connected with a B-phase input end, the first input end of a third optocoupler is connected with a C-phase input end, and the second input end of the first optocoupler, the second input end of the second optocoupler and the second input end of the third optocoupler are all connected with an N-phase input end. The first output end of the first optocoupler is connected with the D end of the first D trigger, the second output end of the first optocoupler is connected with the CLK end of the first D trigger, the second output end of the second optocoupler is connected with the CLK end of the second D trigger, and the second output end of the third optocoupler is connected with the R end of the first D trigger and the R end of the second D trigger. The Q end of the first D trigger is connected with the D end of the second D trigger. According to the utility model, the influence of voltage fluctuation on a post-stage circuit can be avoided.

Description

Technical Field

[0001] The utility model belongs to the technical field of phase sequence detection, in particular to an isolated three-phase phase sequence detection circuit. Background Art

[0002] Currently, the three-phase sequence detection is generally achieved through specific chips or motor forward and reverse rotation observation. The former method is easy to interfere with the circuit, and the latter method cannot be directly recognized by the microprocessor. Utility Model Content

[0003] The utility model aims to overcome the deficiencies of the prior art and provide a three-phase phase sequence detection circuit with isolation.

[0004] The purpose of the utility model is achieved through the following technical solutions: an isolated three-phase phase sequence detection circuit, comprising a first D trigger, a second D trigger, a first optical coupler, a second optical coupler, a third optical coupler, a second resistor, a fourth resistor, a sixth resistor, an A phase input terminal, a B phase input terminal, a C phase input terminal and an N phase input terminal, wherein the first input terminal of the first optical coupler is connected to the A phase input terminal, the first input terminal of the second optical coupler is connected to the B phase input terminal, the first input terminal of the third optical coupler is connected to the C phase input terminal, the second input terminal of the first optical coupler, the second input terminal of the second optical coupler and the second input terminal of the third optical coupler are all connected to the N phase input terminal, The first output end of the first optocoupler is connected to the D end of the first D flip-flop, the second output end of the first optocoupler is connected to the CLK end of the first D flip-flop, the second output end of the first optocoupler is grounded via the second resistor, the second output end of the second optocoupler is connected to the CLK end of the second D flip-flop, the second output end of the second optocoupler is grounded via the fourth resistor, the second output end of the third optocoupler is respectively connected to the R end of the first D flip-flop and the R end of the second D flip-flop, the second output end of the third optocoupler is grounded via the sixth resistor, the Q end of the first D flip-flop is connected to the D end of the second D flip-flop, and the S end of the first D flip-flop and the S end of the second D flip-flop are both grounded.

[0005] Furthermore, the three-phase phase sequence detection circuit also includes a first resistor, a third resistor and a fifth resistor, the first resistor is connected in series between the A-phase input terminal and the first optocoupler, the third resistor is connected in series between the B-phase input terminal and the second optocoupler, and the fifth resistor is connected in series between the C-phase input terminal and the third optocoupler.

[0006] Furthermore, the three-phase phase sequence detection circuit also includes a first diode, a second diode and a third diode, the first diode is connected in series between the A phase input terminal and the first optocoupler, the second diode is connected in series between the B phase input terminal and the second optocoupler, and the third diode is connected in series between the C phase input terminal and the third optocoupler.

[0007] Furthermore, the models of the first diode, the second diode and the third diode are all 1N4007.

[0008] Furthermore, the models of the first optocoupler, the second optocoupler and the third optocoupler are all TLP292.

[0009] The beneficial effects of the utility model are as follows: the detection circuit in the utility model is mainly composed of an optocoupler and a dual D flip-flop, and the optocoupler isolation can prevent voltage fluctuations from affecting the subsequent circuits, and the output level is 5V, which can be directly recognized by processors such as single-chip microcomputers. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The utility model is a circuit diagram of a three-phase phase sequence detection circuit. DETAILED DESCRIPTION

[0011] The following will be combined with the embodiments to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0012] See also Figure 1 , the utility model provides a three-phase phase sequence detection circuit with isolation:

[0013] like Figure 1 As shown, an isolated three-phase phase sequence detection circuit includes a first D trigger U1A, a second D trigger U1B, a first optocoupler J1, a second optocoupler J2, a third optocoupler J3, a second resistor R2, a fourth resistor R4, a sixth resistor R6, an A-phase input terminal, a B-phase input terminal, a C-phase input terminal and an N-phase input terminal.

[0014] The first input end of the first optocoupler J1 is connected to the A-phase input end, and the first input end of the first optocoupler J1 is the anode of the light-emitting diode in the first optocoupler J1; the first input end of the second optocoupler J2 is connected to the B-phase input end, and the second optocoupler J2 is the anode of the light-emitting diode in the second optocoupler J2; the first input end of the third optocoupler J3 is connected to the C-phase input end, and the third optocoupler J3 is the anode of the light-emitting diode in the third optocoupler J3.

[0015] The second input end of the first optocoupler J1, the second input end of the second optocoupler J2 and the second input end of the third optocoupler J3 are all connected to the N-phase input end, the second input end of the first optocoupler J1 is the cathode of the light-emitting diode in the first optocoupler J1, the second input end of the second optocoupler J2 is the cathode of the light-emitting diode in the second optocoupler J2, and the second input end of the third optocoupler J1 is the cathode of the light-emitting diode in the third optocoupler J3.

[0016] The first output end of the first optocoupler J1 is connected to the D end of the first D flip-flop U1A, the second output end of the first optocoupler J1 is connected to the CLK end of the first D flip-flop U1A, the second output end of the first optocoupler J1 is grounded via the second resistor R2, the first output end of the first optocoupler J1 is the collector of the transistor in the first optocoupler J1, and the second output end of the first optocoupler J1 is the emitter of the transistor in the first optocoupler J1.

[0017] The second output end of the second optocoupler J2 is connected to the CLK end of the second D flip-flop U1B, the second output end of the second optocoupler J2 is grounded via the fourth resistor R4, the first output end of the second optocoupler J2 is the collector of the transistor in the second optocoupler J2, and the second output end of the second optocoupler J2 is the emitter of the transistor in the second optocoupler J2.

[0018] The second output end of the third optocoupler J3 is connected to the R end of the first D flip-flop U1A and the R end of the second D flip-flop U1B respectively, and the second output end of the third optocoupler J3 is grounded via the sixth resistor R6. The second output end of the third optocoupler J3 is the emitter of the transistor in the third optocoupler J3.

[0019] A Q terminal of the first D flip-flop U1A is connected to a D terminal of the second D flip-flop U1B, and an S terminal of the first D flip-flop U1A and an S terminal of the second D flip-flop U1B are both grounded.

[0020] In this embodiment, the first optocoupler J1, the second optocoupler J2 and the third optocoupler J3 are used to isolate the AC voltage and convert it into a TTL level. The 5V high level is used as the input of the first D flip-flop U1A, and the input of the second D flip-flop U1B is the output of the first D flip-flop U1A. The A-phase pulse signal is used as the clock signal of the first D flip-flop U1A, the B-phase pulse signal is used as the clock signal of the second D flip-flop U1B, and the C-phase pulse signal is used as the reset signal of the first D flip-flop U1A and the second D flip-flop U1B. According to the truth table, when the phase sequence is correct, the Q end of the second D flip-flop U1B outputs a high level; when the phase sequence is wrong, it outputs a low level. The Q end of the second D flip-flop U1B can be connected to a transistor drive relay or contactor, and the Q end of the second D flip-flop U1B can be used by a microprocessor to detect whether the phase sequence is correct.

[0021] In some embodiments, the three-phase phase sequence detection circuit further includes a first resistor R1, a third resistor R3 and a fifth resistor R5. The first resistor R1 is connected in series between the A-phase input terminal and the first optocoupler J1, that is, one end of the first resistor R1 is connected to the A-phase input terminal, and the other end of the first resistor R1 is connected to the first input terminal of the first optocoupler J1. The third resistor R3 is connected in series between the B-phase input terminal and the second optocoupler J2, that is, one end of the third resistor R3 is connected to the B-phase input terminal, and the other end of the third resistor R3 is connected to the first input terminal of the second optocoupler J2. The fifth resistor R5 is connected in series between the C-phase input terminal and the third optocoupler J3, that is, one end of the fifth resistor R5 is connected to the C-phase input terminal, and the other end of the fifth resistor R5 is connected to the first input terminal of the third optocoupler J3.

[0022] In this embodiment, the first resistor R1 , the third resistor R3 and the fifth resistor R5 are used for current limiting.

[0023] In some embodiments, the three-phase phase sequence detection circuit further includes a first diode D1, a second diode D2, and a third diode D3. The first diode D1 is connected in series between the A-phase input terminal and the first optocoupler J1, that is, the anode of the first diode D1 is connected to the A-phase input terminal, and the cathode of the first diode D1 is connected to the first input terminal of the first optocoupler J1. The second diode D2 is connected in series between the B-phase input terminal and the second optocoupler J2, that is, the anode of the second diode D2 is connected to the B-phase input terminal, and the cathode of the second diode D2 is connected to the first input terminal of the second optocoupler J2. The third diode D3 is connected in series between the C-phase input terminal and the third optocoupler J3, that is, the anode of the third diode D3 is connected to the C-phase input terminal, and the cathode of the third diode D3 is connected to the first input terminal of the third optocoupler J3.

[0024] In this embodiment, the first diode D1 , the second diode D2 and the third diode D3 are used for preventing reverse junction and limiting current.

[0025] In some embodiments, the first diode D1, the second diode D2 and the third diode D3 are all 1N4007, the first optocoupler J1, the second optocoupler J2 and the third optocoupler J3 are all TLP292, the first D flip-flop U1A and the second D flip-flop U1B are both U4013, and the resistance values ​​of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5 and the sixth resistor R6 are all 4.7 kΩ.

[0026] The above is only a preferred embodiment of the utility model. It should be understood that the utility model is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art do not deviate from the spirit and scope of the utility model, and should be within the scope of protection of the claims attached to the utility model.

Claims

1. A three-phase phase sequence detection circuit with isolation, characterized in that: It includes a first D flip-flop, a second D flip-flop, a first optocoupler, a second optocoupler, a third optocoupler, a second resistor, a fourth resistor, a sixth resistor, an A-phase input terminal, a B-phase input terminal, a C-phase input terminal and an N-phase input terminal, wherein the first input terminal of the first optocoupler is connected to the A-phase input terminal, the first input terminal of the second optocoupler is connected to the B-phase input terminal, the first input terminal of the third optocoupler is connected to the C-phase input terminal, the second input terminal of the first optocoupler, the second input terminal of the second optocoupler and the second input terminal of the third optocoupler are all connected to the N-phase input terminal, The first output end of the first optocoupler is connected to the D end of the first D flip-flop, the second output end of the first optocoupler is connected to the CLK end of the first D flip-flop, the second output end of the first optocoupler is grounded via the second resistor, the second output end of the second optocoupler is connected to the CLK end of the second D flip-flop, the second output end of the second optocoupler is grounded via the fourth resistor, the second output end of the third optocoupler is respectively connected to the R end of the first D flip-flop and the R end of the second D flip-flop, the second output end of the third optocoupler is grounded via the sixth resistor, the Q end of the first D flip-flop is connected to the D end of the second D flip-flop, and the S end of the first D flip-flop and the S end of the second D flip-flop are both grounded.

2. The three-phase phase sequence detection circuit with isolation according to claim 1, characterized in that: The three-phase phase sequence detection circuit also includes a first resistor, a third resistor and a fifth resistor, the first resistor is connected in series between the A-phase input terminal and the first optocoupler, the third resistor is connected in series between the B-phase input terminal and the second optocoupler, and the fifth resistor is connected in series between the C-phase input terminal and the third optocoupler.

3. The three-phase phase sequence detection circuit with isolation according to claim 1, characterized in that: The three-phase phase sequence detection circuit also includes a first diode, a second diode and a third diode, the first diode is connected in series between the A-phase input terminal and the first optocoupler, the second diode is connected in series between the B-phase input terminal and the second optocoupler, and the third diode is connected in series between the C-phase input terminal and the third optocoupler.

4. The three-phase phase sequence detection circuit with isolation according to claim 3 is characterized in that: The first diode, the second diode and the third diode are all of 1N4007 type.

5. The three-phase phase sequence detection circuit with isolation according to claim 1, characterized in that: The first optocoupler, the second optocoupler and the third optocoupler are all of model TLP292.

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