Vehicle-mounted power supply switching protection circuit

Abstract

The vehicle-mounted power supply switching protection circuit comprises an AND gate device U1, an AND gate device U2 and a NOT gate device U3D, the input end of the NOT gate device U3D is connected with a pin 2 of one input end of the AND gate device U1, and the output end of the NOT gate device U3D is connected with a pin 1 of one input end of the AND gate device U2. According to the vehicle-mounted power supply switching protection circuit, after the synchronous signal of the input alternating current and the driving pulse signal pass through the AND gate, the output new driving signal is synchronized with the phase of the alternating current signal, and then the MOS tube is driven, so that the damage of the MOS tube caused by the asynchronism of the alternating current input voltage and the driving pulse signal can be effectively avoided, and the reliability of the vehicle-mounted power supply switching protection circuit is improved. Therefore, the inverter can work more safely, efficiently and quickly.

Description

Technical Field

[0001] The present application relates to a vehicle-mounted power switching protection circuit, and in particular to a vehicle-mounted power switching protection circuit in inverter input voltage switching. Background Art

[0002] The integrated charging inverter is a power supply device that can convert the DC power of the battery into AC power for use by the load, and can also convert AC power (mains power or generator) into DC power to charge the battery. Electric energy can flow in both directions in the integrated charging inverter as needed. It is precisely because of its high efficiency and convenience that it has been widely used. At present, the integrated charging inverter is widely used in special vehicles, offices, communication rooms and other places, bringing great convenience to users.

[0003] However, when the inverter is installed in a vehicle such as a motorhome, the input AC power often switches between the mains and the AC generator. Since the mains and AC power are out of phase, the inverter may be damaged during switching. However, the existing circuit cannot solve this problem and further improvement is needed. Utility Model Content

[0004] In order to solve one of the above-mentioned technical defects, an on-board power switching protection circuit is provided in an embodiment of the present application, which can well solve this problem. The circuit drives the MOS tube after the synchronization signal and the drive pulse signal of the input AC power pass through the AND gate, which can effectively avoid the damage of the MOS tube caused by the asynchronism between the AC input voltage and the drive pulse signal, thereby enabling the inverter to work more safely, efficiently and quickly.

[0005] According to a first aspect of an embodiment of the present application, a vehicle-mounted power switching protection circuit is provided, characterized in that it includes: an AND gate device U1, an AND gate device U2 and a NOT gate device U3D, wherein the input terminal pin 4 of the NOT gate device U3D is connected to an input terminal pin 2 of the AND gate device U1, and the output terminal pin 13 of the NOT gate device U3D is connected to an input terminal pin 1 of the AND gate device U2.

[0006] Furthermore, an input terminal 1 of the AND gate device U1 is connected to the driving signal SPWM1.

[0007] Furthermore, an input terminal 2 of the AND gate device U2 is connected to the driving signal SPWM2.

[0008] Furthermore, the pin 4 of the AND gate device U1 is the output terminal of the driving signal SPWM1, and the pin 4 of the AND gate device U2 is the output terminal of the driving signal SPWM2.

[0009] Preferably, the input end of the NOT gate device U3D is connected to a synchronous square wave signal.

[0010] A vehicle-mounted power switching protection circuit provided in an embodiment of the present application is used. The circuit passes the synchronization signal of the input AC power and the drive pulse signal through an AND gate, so that the output new drive signal is phase-synchronized with the AC power signal, and then drives the MOS tube. This can effectively avoid damage to the MOS tube caused by the lack of synchronization between the AC input voltage and the drive pulse signal, thereby enabling the inverter to work more safely, efficiently and quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0012] Figure 1 A schematic diagram of the structure of a vehicle power switching protection circuit provided in an embodiment of the present application. DETAILED DESCRIPTION

[0013] In order to make the technical solutions and advantages in the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0014] The present application discloses a vehicle-mounted power switching protection circuit. The circuit synchronizes the phase of the output new driving signal with the AC signal after the AC input synchronization signal and the driving pulse signal pass through an AND gate, and then drives the MOS tube. This circuit can effectively avoid the damage of the MOS tube caused by the asynchronism between the AC input voltage and the driving pulse signal, so that the inverter can work more safely, efficiently and quickly. Figure 1 As shown, the vehicle-mounted power switching protection circuit includes two AND gates U1 and U2 and a NOT gate U3D. Among them, the 1st pin of the AND gate U1 is connected to the drive signal SPWM1, the 2nd pin is connected to the synchronous square wave, the 3rd pin is grounded, the 4th pin is the drive signal output pin, and the 5th pin is connected to the power supply; the 1st pin of the AND gate U2 is connected to the output pin 13th pin of the NOT gate U3D, the 2nd pin is connected to the drive signal SPWM2, the 3rd pin is grounded, the 4th pin is the drive signal output pin, and the 5th pin is connected to the power supply; the input pin 4th pin of the NOT gate U3D is connected to the synchronous square wave, and the output pin 13th pin is connected to the 1st pin of the NOT gate U2.

[0015] Figure 1 This is a schematic diagram of an application of a vehicle-mounted power switching protection circuit of the utility model, such as Figure 1 As shown, in this embodiment, the improved voltage regulation circuit is used to protect the inverter when the input voltage is switched. During operation, Figure 1The "SPWM1" terminal in the circuit is connected to the SPWM1 drive pulse signal output pin of the microprocessor. Figure 1 The "SPWM2" terminal in the circuit is connected to the SPWM2 drive pulse signal output pin of the microprocessor. Figure 1 The "SPWM-1" terminal in is connected to the inverter switch tube 1. Figure 1 The "SPWM-2" terminal in is connected to the inverter switch tube 2, and the "synchronous square wave" terminal is connected to the synchronous square wave voltage terminal of the AC input voltage. When the inverter has an external AC power input, the inverter is working in the charging state. At this time, the inverter will detect the phase of the AC input voltage and generate a synchronous square wave signal synchronized with the input AC voltage. This synchronous square wave signal will be transmitted to the microprocessor. The microprocessor will then generate a drive pulse signal synchronized with the input AC voltage according to this synchronization signal to drive the switch tube, so that the circuit works in the charging state. However, when the input voltage is switched from the mains to the generator, since the phase of the mains voltage is different from the phase of the generator voltage, the switching will cause a sudden change in the phase of the input voltage. At this time, if the microprocessor does not have time to make adjustments, the drive pulse and the input voltage will be out of sync. If it is not protected, the inverter switch tube will burn out, causing damage to the inverter. At this time Figure 1 The protection circuit in the circuit will play a protective role. When the input voltage phase changes suddenly, the synchronous square wave signal will change with the input voltage phase. Figure 1 The synchronization square wave in the AND gate will be out of sync with the drive pulse signals SPWM1 and SPWM2, because the output pin 4 of the AND gate can only be high when pins 1 and 2 are high at the same time. Therefore, when the synchronization square wave is out of sync with the drive pulse signals SPWM1 and SPWM2, the output pin 4 of the AND gates U1 and U2 will become a low level, thereby locking the drive pulse and protecting the switch tube from damage, thereby protecting the inverter from damage.

[0016] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0017] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A vehicle-mounted power switching protection circuit, characterized in that: include: AND gate device U1, AND gate device U2 and NOT gate device U3D, the input terminal pin 4 of the NOT gate device U3D is connected to an input terminal pin 2 of the AND gate device U1, and the output terminal pin 13 of the NOT gate device U3D is connected to an input terminal pin 1 of the AND gate device U2.

2. The vehicle-mounted power switching protection circuit according to claim 1, characterized in that: An input terminal 1 of the AND gate device U1 is connected to the driving signal SPWM1.

3. The vehicle-mounted power switching protection circuit according to claim 1, characterized in that: An input terminal 2 of the AND gate device U2 is connected to the driving signal SPWM2.

4. The vehicle-mounted power switching protection circuit according to claim 2, characterized in that: The input end of the NOT gate device U3D is connected to a synchronous square wave signal.

5. The vehicle-mounted power switching protection circuit according to claim 3, characterized in that: Pin 4 of the AND gate device U1 is an output terminal of the driving signal SPWM1, and pin 4 of the AND gate device U2 is an output terminal of the driving signal SPWM2.

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