Low-voltage excitation self-voltage-stabilizing circuit of generator

Abstract

The utility model relates to a generator low-voltage excitation self-voltage-stabilizing circuit comprising a clamping circuit, two input ends of which are DC excitation input ends; the direct-current excitation input end is used for accessing the rectified voltage of the phase voltage of the generator; the control electrode of the first switch tube is connected to the first output end of the clamping circuit; the control electrode of the second switch tube is connected to the second output end of the clamping circuit; when the second switch tube is switched on, the voltage transmission circuit transmits the voltage signal of the second output end of the clamping circuit to the excitation winding end of the generator; the self-voltage-stabilizing and protection circuit has lower excitation voltage and also has self-voltage-stabilizing and protection functions.

Description

Technical Field

[0001] This utility model relates to electronic circuit technology, specifically to a low-voltage excitation self-stabilizing circuit for a generator. Background Technology

[0002] The power supply system of a digital voltage regulator (AVR) is more complex than that of an analog voltage regulator, mainly due to its more comprehensive functions, including more precise sampling and communication capabilities. For a digital voltage regulator system to start up fully and normally, it generally requires a transition circuit and a higher start-up voltage.

[0003] In the prior art, the starting excitation voltage of digital regulators is relatively high, generally around 10V, and they do not have self-regulation function. For example, the technical solution mentioned in the patent document CN211352090U, which was authorized on August 25, 2020, and has the authorization announcement number CN211352090U, has a high starting excitation voltage, a complex circuit structure, and does not have self-regulation function. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model discloses a low-voltage excitation self-stabilizing circuit for generators.

[0005] The technical solution adopted in this utility model is as follows:

[0006] A generator low-voltage excitation self-regulating circuit includes:

[0007] The clamping circuit has two input terminals that are DC excitation input terminals; the DC excitation input terminals are used to connect the rectified voltage of the generator phase voltage.

[0008] The first switching transistor is connected to the first output terminal of the clamping circuit.

[0009] The control electrode of the second switching transistor is connected to the second output terminal of the clamping circuit.

[0010] The voltage conduction circuit, when the second switch is turned on, conducts the voltage signal from the second output terminal of the clamping circuit to the excitation winding terminal of the generator.

[0011] When the voltage at the two input terminals of the clamping circuit is lower than the conduction voltage of the clamping circuit, the first switch is turned off and the second switch is turned on; when the voltage at the two input terminals of the clamping circuit is higher than the conduction voltage of the clamping circuit, the first switch is turned on and the second switch is turned off.

[0012] A further technical solution is that the clamping circuit includes a clamping diode; the cathode end of the clamping diode is the second output terminal of the clamping circuit, and the anode end of the clamping diode is the first output terminal of the clamping circuit.

[0013] A further technical solution is that the clamping diode includes a first diode and a second diode connected in series; the first diode is a Zener diode; and the second diode is an avalanche diode.

[0014] A further technical solution is that the clamping circuit further includes a first capacitor and a first series branch connected in parallel with the first capacitor; the first series branch includes a first resistor, a first diode, a second diode, and a second resistor connected in series in sequence; the common terminal of the second diode and the second resistor serves as the first output terminal of the clamping circuit and is connected to the control electrode of the first switching transistor; the first end of the first series branch serves as the second output terminal of the clamping circuit and is connected to the control electrode of the second switching transistor.

[0015] A further technical solution is that a second series branch consisting of a third resistor and a fourth resistor connected in series is connected to the control electrode of the second switching transistor; the first end of the second series branch is connected to the first end of the first series branch, and the second end of the second series branch is connected to the control electrode of the second switching transistor; the common end of the third resistor and the fourth resistor is connected to the first current-conducting electrode of the first switching transistor.

[0016] A further technical solution is that the voltage conduction circuit includes a fifth resistor, the two ends of which are respectively connected to the first current-conducting electrode of the second switching transistor and the excitation winding terminal.

[0017] A further technical solution is that the first switching transistor is a triode; the control electrode of the first switching transistor is the base of the triode, and the first current-conducting electrode and the second current-conducting electrode of the first switching transistor are the collector and emitter of the triode, respectively.

[0018] A further technical solution is that the second switch is a field-effect transistor (FET); the controller of the second switch is the gate of the FET, and the first current-conducting electrode and the second current-conducting electrode of the second switch are the source and drain of the FET, respectively.

[0019] A further technical solution is that the self-regulating voltage circuit is used as a transition circuit for the digital drive circuit; the digital drive circuit includes a drive power transistor; the gate of the drive power transistor is used to input digital drive signals, and the drain and source of the drive power transistor are respectively connected to the excitation winding terminal and the ground terminal.

[0020] The beneficial effects of this utility model are as follows:

[0021] The technical solution disclosed in this utility model is a transition circuit before the full start-up of a digital voltage regulator.

[0022] The circuit disclosed in this utility model has a lower trigger voltage. The trigger voltage only needs to be the sum of the gate turn-on voltage of the second switching transistor and the conduction voltage drop of the rectifier bridge. As needed, a field-effect transistor with a lower turn-on voltage and a rectifier bridge with a lower voltage drop can be selected to pursue a lower trigger voltage.

[0023] The circuit disclosed in this utility model also has self-regulation and protection functions. When the digital drive circuit fails, the excitation self-regulating circuit can maintain the generator output value around the critical value. This voltage can be used for the operation of alarm, lighting and other systems, providing a buffer time for fault handling and improving the stability of the system. Moreover, the critical value of the excitation self-regulating circuit is adjustable. It is only necessary to adjust the type of clamping diode and select the required reverse breakdown voltage. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the circuit structure of an embodiment of the present utility model. Detailed Implementation

[0025] The specific embodiments of this utility model are described below with reference to the accompanying drawings.

[0026] This utility model embodiment provides a generator low-voltage excitation self-stabilizing circuit. Figure 1 This is a schematic diagram of the circuit structure of an embodiment of the present utility model. Figure 1 As shown, the input terminal of the self-regulating excitation circuit is the DC excitation input terminal J1, which is used to connect the generator phase voltage after rectification by the rectifier bridge. The output terminal of the self-regulating excitation circuit is the excitation winding terminal J2, which is used to connect the generator excitation winding. The self-regulating excitation circuit includes a clamping circuit, a first switching transistor Q1, a second switching transistor V1, and a voltage conduction circuit.

[0027] In this embodiment, preferably, the first switch Q1 is a transistor, with its base as the control electrode and its collector and emitter as the first and second current-carrying electrodes, respectively. The second switch V1 is a field-effect transistor (FET), with its gate as the control electrode and its source and drain as the first and second current-carrying electrodes, respectively. In other embodiments, the first switch Q1 and the second switch V1 can be replaced with other electronic components or circuit structures with the same function.

[0028] The two input terminals of the clamping circuit are also the DC excitation input terminals J1, and the two output terminals of the clamping circuit are used to provide turn-on voltages to the control terminals of the first switching transistor Q1 and the second switching transistor V1, respectively.

[0029] The clamping circuit includes a clamping diode. The cathode of the clamping diode is the second output terminal of the clamping circuit, and the anode is the first output terminal. Here, "cathode" or "anode" can refer to the cathode or anode being directly used as the output terminal, or it can refer to the cathode or anode being connected in series with other circuit elements such as resistors. When the voltage applied to the two input terminals of the clamping circuit is higher than the clamping circuit's turn-on voltage, the clamping diode conducts in reverse. The voltage at the control electrode of the first switch Q1 is higher than the turn-on voltage of the first switch Q1, so the first switch Q1 conducts. The voltage at the control electrode of the second switch V1 is lower than the turn-on voltage of the second switch V1, so the second switch V1 is turned off. When the voltage applied to the two input terminals of the clamping circuit is lower than the clamping circuit's turn-on voltage, the clamping diode does not conduct, the first switch Q1 is turned off, and the second switch V1 conducts.

[0030] Furthermore, such as Figure 1 As shown, in this embodiment, the clamping diode includes a first diode D1 and a second diode D2 connected in series. The first diode D1 is a Zener diode. The second diode D2 is an avalanche diode.

[0031] Furthermore, the clamping circuit also includes a first capacitor C1 and a first series branch connected in parallel with the first capacitor C1. The first series branch includes a first resistor R1, a first diode D1, a second diode D2, and a second resistor R2 connected in series. The common terminal of the second diode D2 and the second resistor R2 serves as the first output terminal of the clamping circuit and is connected to the control electrode of the first switching transistor Q1. The first end of the first series branch serves as the second output terminal of the clamping circuit and is connected to the control electrode of the second switching transistor V1. The second end of the first series branch is connected to ground. Connections here and elsewhere in this document include direct connections as well as connections via basic circuit elements such as resistors.

[0032] In this embodiment, a second series branch, consisting of a third resistor R3 and a fourth resistor R4 connected in series, is also connected to the control electrode of the second switch V1. The first end of the second series branch is connected to the first end of the first series branch, and the second end of the second series branch is connected to the control electrode of the second switch V1. The common terminal of the third resistor R3 and the fourth resistor R4 is connected to the first current-carrying electrode of the first switch Q1. The third resistor R3 and the fourth resistor R4 can be used to adjust the voltage at the control electrodes of the second switch V1 and the first switch Q1, so that they can reach the corresponding turn-on voltage under corresponding conditions.

[0033] The self-regulating voltage circuit also includes a voltage conduction circuit. When the second switching transistor is turned on, the voltage conduction circuit transfers the voltage signal from the second output terminal of the clamping circuit to the excitation winding terminal. Here, conduction refers to transmitting the voltage signal to the excitation winding terminal while maintaining its amplitude or proportionally adjusting it. In this embodiment, the voltage conduction circuit includes a fifth resistor R5. The first end of the fifth resistor R5 is connected to the first current-carrying electrode of the second switching transistor V1, and the second end of the fifth resistor R5 is connected to the excitation winding terminal J2.

[0034] Furthermore, such as Figure 1 As shown, the self-regulating voltage circuit serves as the startup transition circuit for the digital drive circuit. The digital drive circuit includes a drive power transistor V2. V2 is an IGBT transistor, with its gate connected to the drive signal input terminal G. Its drain and source are connected to the excitation winding terminal J2 and the ground terminal, respectively. As shown, a sixth resistor R6 and a fifth diode D5 are connected in parallel between the gate and ground terminal of the drive power transistor V2.

[0035] The working process and working principle of the present invention will be described below.

[0036] When the digital driving circuit in this embodiment of the present invention is working normally:

[0037] Phase 1: The diesel (gasoline) engine rotates, driving the generator. At this stage, the generator's initial output voltage is typically below 10V. This initial voltage is too low to activate the digital drive circuit on the digital voltage regulator, which includes the CPU and sampling chip. Therefore, a drive signal cannot be provided to the gate of the power transistor V2 through the drive signal input terminal G. During this phase, the drive signal input terminal G is always a "non-conducting signal." In this embodiment, the reverse breakdown voltage of the first diode D1 is 68V, and the reverse breakdown voltage of the second diode D2 is 5.6V. In the clamping circuit, specifically the loop formed by the first resistor R1, the second resistor R2, the first diode D1, the second diode D2, and the first capacitor C1, due to the voltage clamping effect of the first diode D1 and the second diode D2, when the voltage across the first capacitor C1 is lower than 73.6V (in reality, there may be a deviation of a few volts due to device and circuit operating environment), the base voltage of the first switching transistor Q1 has not reached its turn-on voltage. At this time, the initial voltage of the first capacitor C1 is applied to the gate of the second switching transistor V1 through the third resistor R3 and the fourth resistor R4, and the second switching transistor V1 conducts normally. This voltage then passes through the fifth resistor R5 and is applied to the excitation winding terminal J2. In other words, the initial voltage of the first capacitor C1 acts on the excitation coil, forming an excitation current that begins to increase the generator voltage.

[0038] Second stage: When the voltage of the first capacitor C1 reaches about 20V, all the components in the digital drive circuit can work normally. At this time, the system starts to operate. The CPU and related drive circuits generate a reasonable conduction signal to the drive signal input terminal G, and the gate of the drive power transistor V2 receives the correct drive signal. Through the excitation winding terminal J2, the output voltage of the generator is maintained at the preset value (usually 380V or 400V).

[0039] When the digital driving circuit in this embodiment of the present invention is not working properly:

[0040] This abnormal operation may be set to meet the normal control requirements of the control system, or it may be caused by a system malfunction. In this case, the digital drive circuit will not receive a drive signal input to the drive signal input terminal G.

[0041] The first stage is the same as the first stage when the digital drive circuit is working normally.

[0042] Second stage: The generator output voltage gradually increases, and the input voltage of the DC excitation input terminal J1 also increases accordingly. At this time, the excitation current also increases, and the positive feedback further promotes the generator voltage to increase until it exceeds the critical value of 73.6V reverse breakdown voltage of the clamping diode in the clamping circuit. The base voltage of the first switch Q1 reaches its turn-on voltage. After the first switch Q1 is turned on, the gate voltage of the second switch V1 is pulled down, and the second switch V1 is turned off. At this time, the excitation current loop is broken, and the generator excitation current decreases, causing the generator output voltage to decrease accordingly. After decreasing to below the critical value of 73.6V, it re-enters the first stage.

[0043] Based on the above working process and principle, it can be seen that the excitation voltage of this utility model embodiment can be very low, as low as the initial voltage of only 5V phase voltage (the voltage of the first capacitor C1 after rectification is at least about 5*1.414≈7V). In fact, it is sufficient to reach the sum of the gate turn-on voltage of the second switching transistor V1 and the conduction voltage drop of the rectifier bridge (generally about 0.8V). In other words, if necessary, a field-effect transistor with a lower turn-on voltage and a rectifier bridge with a lower voltage drop can be selected to pursue a lower trigger voltage.

[0044] When the digital drive circuit fails, the self-regulating excitation circuit can maintain the generator output value around the critical value. This voltage can be used for the operation of alarm, lighting and other systems, providing a buffer time for fault handling and improving system stability. Moreover, the critical value of the self-regulating excitation circuit is adjustable. It is only necessary to adjust the type of clamping diode and select the required reverse breakdown voltage.

[0045] The above description is an explanation of the present utility model and not a limitation thereof. The scope of the present utility model is defined by the claims. The present utility model can be modified in any form without departing from its basic structure.

Claims

1. A low voltage self-excitation and self-regulation circuit for a generator, characterized in that, include: The clamping circuit has two input terminals that are DC excitation input terminals; the DC excitation input terminals are used to connect the rectified voltage of the generator phase voltage. The first switching transistor is connected to the first output terminal of the clamping circuit. The control electrode of the second switching transistor is connected to the second output terminal of the clamping circuit. The voltage conduction circuit, when the second switch is turned on, conducts the voltage signal from the second output terminal of the clamping circuit to the excitation winding terminal of the generator. When the voltage at the two input terminals of the clamping circuit is lower than the conduction voltage of the clamping circuit, the first switch is turned off and the second switch is turned on; when the voltage at the two input terminals of the clamping circuit is higher than the conduction voltage of the clamping circuit, the first switch is turned on and the second switch is turned off.

2. The generator low voltage self-excitation and self-regulation circuit according to claim 1, characterized in that, The clamping circuit includes a clamping diode; the cathode end of the clamping diode is the second output terminal of the clamping circuit, and the anode end of the clamping diode is the first output terminal of the clamping circuit.

3. The generator low-voltage excitation self-regulating circuit according to claim 2, characterized in that, The clamping diode consists of a first diode and a second diode connected in series; the first diode is a Zener diode; and the second diode is an avalanche diode.

4. The generator low voltage self-excited field and regulated voltage circuit of claim 3 wherein, The clamping circuit also includes a first capacitor and a first series branch connected in parallel with the first capacitor; the first series branch includes a first resistor, a first diode, a second diode, and a second resistor connected in series in sequence; the common terminal of the second diode and the second resistor serves as the first output terminal of the clamping circuit and is connected to the control electrode of the first switching transistor; the first end of the first series branch serves as the second output terminal of the clamping circuit and is connected to the control electrode of the second switching transistor.

5. The generator low-voltage excitation self-regulating circuit according to claim 4, characterized in that, A second series branch, consisting of a third resistor and a fourth resistor connected in series, is also connected to the control electrode of the second switching transistor. The first end of the second series branch is connected to the first end of the first series branch, and the second end of the second series branch is connected to the control electrode of the second switching transistor. The common terminal of the third resistor and the fourth resistor is connected to the first current-conducting electrode of the first switching transistor.

6. The generator low-voltage excitation self-regulating circuit according to claim 1, characterized in that, The voltage conduction circuit includes a fifth resistor, the two ends of which are respectively connected to the first current-conducting electrode of the second switching transistor and the excitation winding terminal.

7. The generator low voltage self-excited field and regulated voltage circuit of claim 1 wherein, The first switching transistor is a bipolar transistor; the control terminal of the first switching transistor is the base of the bipolar transistor, and the first current-carrying terminal and the second current-carrying terminal of the first switching transistor are the collector and emitter of the bipolar transistor, respectively.

8. The generator low-voltage excitation self-regulating circuit according to claim 1, characterized in that, The second switch is a field-effect transistor (FET); the control electrode of the second switch is the gate of the FET, and the first current-conducting electrode and the second current-conducting electrode of the second switch are the source and drain of the FET, respectively.

9. The generator low voltage self-excited and regulated power supply circuit according to claim 1, characterized by, The self-regulating circuit is used as a transition circuit for the digital drive circuit; the digital drive circuit includes a drive power transistor; the gate of the drive power transistor is used to input digital drive signals, and the drain and source of the drive power transistor are respectively connected to the excitation winding terminal and the ground terminal.

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