Silicon controlled rectifier alternating current voltage regulating system capable of preventing half wave

Abstract

The utility model relates to the technical field of alternating current voltage regulation, in particular to a silicon controlled rectifier alternating current voltage regulation system capable of preventing half waves, which comprises a rectifier bridge, a silicon controlled rectifier, a transformer and a trigger circuit. A first node of the rectifier bridge is connected to an AC power supply, a third node is connected in series with one end of a transformer initial coil, and the other end of the transformer initial coil is connected to the AC power supply; the silicon controlled rectifier is connected between the second node and the fourth node of the rectifier bridge; the rectifier bridge comprises four diodes which are all connected with the silicon controlled rectifier in an anti-parallel mode. The trigger circuit is connected with a control electrode of the silicon controlled rectifier and sends a trigger signal to the silicon controlled rectifier to control on and off of the silicon controlled rectifier. According to the utility model, the occurrence of half-wave faults can be effectively prevented, and the technical problem of possible half-wave faults in the existing silicon controlled alternating current voltage regulation system is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of AC voltage regulation, in particular to a half-wave-preventing silicon controlled AC voltage regulation system. Background Art

[0002] AC voltage regulation circuits are widely used in modern industry, especially in high voltage and low current, or low voltage and high current DC power supplies. SCR AC voltage regulation system is often used to regulate the primary voltage of the transformer. The circuit principle is as follows: Figure 1 The existing thyristor AC voltage regulation system includes two reverse parallel thyristors, the conduction and cutoff of the two thyristors are precisely controlled by a special trigger circuit to ensure that the AC voltage regulation circuit maintains corresponding positive and reverse conduction in the positive and negative half cycles of the AC power.

[0003] However, in the existing thyristor AC voltage regulation system, if one of the thyristor trigger circuits fails, it is easy to cause a half-wave fault in the AC voltage regulation circuit, resulting in instability of the circuit. The half-wave fault waveform is as follows: Figure 2 As shown in the figure, if the load of the half-wave fault is a transformer, a DC short circuit will be formed, and in severe cases, the transformer coil may be burned out. Therefore, it is extremely important to design a thyristor AC voltage regulation system and solve the problem of half-wave faults that may occur in existing thyristor AC voltage regulation systems. Utility Model Content

[0004] The purpose of the present application is to provide a half-wave-proof thyristor AC voltage regulation system, which solves the technical problem of half-wave faults that may occur in existing thyristor AC voltage regulation systems.

[0005] In order to solve the above technical problems, the solution adopted by this application is as follows:

[0006] The utility model provides a half-wave-preventing thyristor AC voltage regulation system, which is characterized by comprising a rectifier bridge, a thyristor and a transformer; the first node of the rectifier bridge is connected to an AC power supply, the third node of the rectifier bridge is connected in series with one end of an initial coil of the transformer, and the other end of the initial coil of the transformer is connected to the AC power supply; the thyristor is connected between the second node and the fourth node of the rectifier bridge.

[0007] In some embodiments, the positive electrode of the thyristor is connected to the second node of the rectifier bridge, and the negative electrode of the thyristor is connected to the fourth node of the rectifier bridge.

[0008] In some embodiments, the rectifier bridge is a single-phase rectifier bridge, and the single-phase rectifier bridge includes four diodes, and the four diodes are all connected in reverse parallel with the thyristor.

[0009] In some embodiments, a trigger circuit is also included, wherein the trigger circuit is connected to the control electrode of the thyristor, and the trigger circuit sends a trigger signal to the thyristor to control the conduction and cutoff of the thyristor.

[0010] The technical solution of the present application has at least the following advantages and beneficial effects:

[0011] The utility model adopts a single thyristor for voltage regulation, and the output waveform is still an AC full wave, with low cost and simple circuit structure. The single thyristor withstands forward voltage within one cycle and is not easily impacted by reverse voltage, which can effectively improve the stability of the system. If the trigger system of the single thyristor fails, the AC voltage regulation system has no waveform output, which can effectively prevent the occurrence of half-wave faults and thus protect the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a single-phase AC voltage regulation circuit diagram for an existing transformer load;

[0013] Figure 2 It is a half-wave fault waveform diagram;

[0014] Figure 3 This is a diagram of the thyristor AC voltage regulation system of the utility model;

[0015] Figure 4 The voltage waveform diagram of the thyristor in the thyristor AC voltage regulation system of the utility model is borne by the thyristor;

[0016] Figure 5 This is an output waveform diagram of the thyristor AC voltage regulation system of the utility model. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments 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 in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in the subsequent figures. If the terms "center", "upper", "lower", "inner", "outer", etc. indicate an orientation or position relationship based on the orientation or position relationship shown in the figure, or the orientation or position relationship in which the product of the application is usually placed when in use, it is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. It should also be noted that unless otherwise clearly specified and limited, if the terms "set", "install", and "connect" appear, they should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be a connection between the two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0019] Example 1

[0020] Please refer to Figure 1-Figure 5 The utility model provides a half-wave-preventing thyristor AC voltage regulation system, comprising a rectifier bridge, a thyristor, and a transformer; the first node of the rectifier bridge is connected to an AC power supply, the third node is connected in series with one end of an initial coil of the transformer, and the other end of the initial coil of the transformer is connected to the AC power supply; the positive electrode of the thyristor is connected to the second node of the rectifier bridge, and the negative electrode is connected to the fourth node of the rectifier bridge; the rectifier bridge is a single-phase rectifier bridge, which comprises four diodes, and the four diodes are all connected in reverse parallel with the thyristor.

[0021] The utility model also includes a trigger circuit, which is connected to the control electrode of the thyristor. The trigger circuit sends a trigger signal to the thyristor to control the conduction and cutoff of the thyristor. In each cycle of the utility model, the trigger circuit sends two trigger signals to the thyristor VT1.

[0022] In this embodiment, the trigger circuit belongs to the prior art and will not be described in detail here.

[0023] like Figure 3 As shown, the thyristor AC voltage regulation system of the utility model includes a rectifier bridge D1, a thyristor VT1, and a transformer TM; for the convenience of description, in the rectifier bridge D1, the diode in the upper left corner is called the first diode, the diode in the upper right corner is called the second diode, the diode in the lower left corner is called the third diode, and the diode in the lower right corner is called the second diode;

[0024] Furthermore, in the thyristor AC voltage regulation system, the anode of the first diode is connected to the cathode of the third diode and connected to the AC power supply, and the connection point here is called the first node of the rectifier circuit D1; the cathode of the first diode, the cathode of the second diode, and the anode of the thyristor VT1 are connected, and the connection point here is called the second node of the rectifier circuit D1; the cathode of the thyristor VT1, the anode of the third diode, and the anode of the fourth diode are connected, and the connection point here is called the fourth node of the rectifier circuit D1; the anode of the second diode, the cathode of the fourth diode, and one end of the initial coil of the transformer TM are connected, and the connection point here is called the third node of the rectifier circuit D1; the other end of the initial coil of the transformer TM is connected to the AC power supply.

[0025] It should be noted that the circuit signal flow path of the thyristor AC voltage regulation system in this embodiment is as follows:

[0026] The AC power supply is supplying power through its positive half-wave cycle, that is, when the AC power supply is a positive voltage at the first node of the rectifier circuit D1 and a negative voltage at the other end of the initial coil of the transformer TM, the second diode and the third diode are in the cut-off state, and the first diode, the thyristor VT1, and the fourth diode are in the on state; at this time, the first diode, the thyristor VT1, the fourth diode, and the initial coil of the transformer TM are connected to form a current loop, and the AC power starts from the positive pole of the power supply, passes through the first diode, the thyristor VT1, the fourth diode, and the initial coil of the transformer TM in turn, and finally returns to the negative pole of the power supply.

[0027] The AC power supply is supplying power through its negative half-wave cycle, that is, when the AC power supply is a positive voltage at the other end of the initial coil of the transformer TM and a negative voltage at the first node of the rectifier circuit D1, the first diode and the fourth diode are in the cut-off state, and the second diode, the thyristor VT1, and the third diode are in the on state; at this time, the second diode, the thyristor VT1, the third diode, and the initial coil of the transformer TM are connected to form a current loop, and the AC power starts from the negative pole of the power supply, passes through the initial coil of the transformer TM, the second diode, the thyristor VT1, the third diode in sequence, and finally returns to the negative pole of the power supply.

[0028] like Figure 4 As shown, in the thyristor AC voltage regulation system, the voltage that the thyristor bears in one cycle is all forward voltage, and it is not easily impacted by reverse voltage, which can effectively improve the stability of the system.

[0029] like Figure 5 As shown, the waveform output by the thyristor AC voltage regulation system is consistent with the waveform of the traditional thyristor AC voltage regulation system, and the output waveform is still an AC full wave.

[0030] So far, various embodiments of the present invention have been described in detail. In order to avoid obscuring the concept of the present invention, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution of the present invention, and the scope of the present invention is defined by the attached claims.

Claims

1. A half-wave-preventing silicon controlled AC voltage regulation system, characterized in that: It includes a rectifier bridge, a thyristor, and a transformer; the first node of the rectifier bridge is connected to an AC power supply, the third node of the rectifier bridge is connected in series with one end of an initial coil of the transformer, and the other end of the initial coil of the transformer is connected to an AC power supply; the thyristor is connected between the second node and the fourth node of the rectifier bridge.

2. A half-wave-preventing silicon controlled rectifier AC voltage regulation system according to claim 1, characterized in that: The positive electrode of the thyristor is connected to the second node of the rectifier bridge, and the negative electrode of the thyristor is connected to the fourth node of the rectifier bridge.

3. The half-wave-preventing silicon controlled rectifier AC voltage regulation system according to claim 1, characterized in that: The rectifier bridge is a single-phase rectifier bridge, and the single-phase rectifier bridge comprises a first diode, a second diode, a third diode, and a fourth diode, and the four diodes are all connected in reverse parallel with the thyristor.

4. A half-wave-preventing silicon controlled rectifier AC voltage regulation system according to claim 3, characterized in that: When the AC power supply is supplying power through its positive half-wave cycle, the first diode, thyristor VT1, the fourth diode, and the initial coil of the transformer TM are connected to form a current loop. The AC power starts from the positive pole of the power supply, passes through the first diode, thyristor VT1, the fourth diode, the initial coil of the transformer TM in sequence, and finally returns to the negative pole of the power supply.

5. The half-wave-preventing silicon controlled rectifier AC voltage regulation system according to claim 3, characterized in that: When the AC power supply is supplying power through its negative half-wave cycle, the second diode, thyristor VT1, the third diode, and the initial coil of the transformer TM are connected to form a current loop. The AC power starts from the negative pole of the power supply, passes through the initial coil of the transformer TM, the second diode, the thyristor VT1, the third diode in sequence, and finally returns to the negative pole of the power supply.

6. The half-wave-preventing silicon controlled rectifier AC voltage regulation system according to claim 1, characterized in that: It also includes a trigger circuit, which is connected to the control electrode of the thyristor. The trigger circuit sends a trigger signal to the thyristor to control the conduction and cut-off of the thyristor.

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