Charger with input overvoltage protection

Abstract

The utility model discloses a charger with input overvoltage protection, and relates to the technical field of electric vehicles, the charger comprises a first transformation circuit, a sampling module, a PWM chip and a drive circuit, the input end of the first transformation circuit is connected with the input end of the charger, and the output end of the first transformation circuit is the output end of the charger; the input end of the sampling module is connected with the input end of the first voltage transformation circuit, the output end of the sampling module is connected with the signal input end of the PWM chip, the signal output end of the PWM chip is connected with the control end of the driving circuit, and the driving circuit is arranged at the input end of the first voltage transformation circuit. The input voltage of the power supply end of the charger is obtained through the sampling module, whether the current actual input voltage exceeds the preset maximum value or not is compared through the PWM chip, and under the condition that the current actual input voltage exceeds the maximum value, the driving circuit stops driving, the charger stops working, and the charger is protected from being burnt out by high voltage.

Description

Technical Field

[0001] The utility model relates to the technical field of electric vehicles, in particular to a charger with input overvoltage protection. Background Art

[0002] The current new national standard charger requires that the input voltage of the charger does not change much. Generally, it is still ±20% of the rated input voltage, that is, it is calculated using 220V AC mains, and it is required to work normally during the period of 176V-264V. There is no hard and fast regulation for less than 176V and greater than 264V. However, in actual use, the input voltage is greater than 264V. Therefore, it is necessary to enter the protection state when the input voltage is too high to avoid device damage. Utility Model Content

[0003] Based on the above problems, the utility model provides a charger with input overvoltage protection, which can enter a protection state when the input voltage is too high to avoid device damage.

[0004] The utility model embodiment discloses the following technical solution:

[0005] In a first aspect, the present application provides a charger with input overvoltage protection, comprising a first voltage conversion circuit, a sampling module, a PWM chip, and a driving circuit.

[0006] The input end of the first voltage conversion circuit is connected to the input end of the charger, and the output end of the first voltage conversion circuit is the output end of the charger;

[0007] The input end of the sampling module is connected to the input end of the first transformer circuit, the output end of the sampling module is connected to the signal input end of the PWM chip, the signal output end of the PWM chip is connected to the control end of the drive circuit, and the drive circuit is arranged at the input end of the first transformer circuit.

[0008] Optionally, the first transformer circuit includes a high-frequency transformer, a first rectifier, and a first filter. The input end of the high-frequency transformer is the input end of the first transformer circuit, the positive output end of the high-frequency transformer is connected to the input end of the first rectifier, the output end of the first rectifier is connected to the input end of the first filter, the output end of the first filter is the positive output end of the charger, and the negative output end of the high-frequency transformer is the negative output end of the charger.

[0009] Optionally, it also includes an auxiliary power supply, a resistor R1, a diode D1, and a capacitor C1, the positive electrode of the auxiliary power supply is connected to the first end of the resistor R1, the second end of the resistor R1 is connected to the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to the power supply end of the PWM chip, the positive electrode of the capacitor C1 is connected to the negative electrode of the diode D1, and the negative electrode of the capacitor C1 and the negative electrode of the auxiliary power supply are both grounded.

[0010] Optionally, the driving circuit includes a switch MOS tube, and the switch MOS tube is used to turn on or off the circuit at the input end of the first transformer circuit.

[0011] Optionally, the input terminal of the charger is connected to direct current.

[0012] Optionally, the input end of the charger is connected to alternating current and also includes an AC / DC conversion circuit, the input end of the charger is connected to the input end of the AC / DC conversion circuit, and the output end of the AC / DC conversion circuit is connected to the input end of the first transformer circuit.

[0013] Optionally, the AC / DC conversion circuit includes a surge protector, an electromagnetic compatibility (EMC), a second rectifier, and a second filter. The surge protector is connected to alternating current, the output end of the surge protector is connected to the input end of the electromagnetic compatibility (EMC), the output end of the electromagnetic compatibility (EMC) is connected to the second rectifier, the output end of the second rectifier is connected to the input end of the second filter, and the output end of the second filter is connected to the input end of the first transformer circuit.

[0014] Optionally, the sampling module includes a resistor R2E, a resistor R2H, a resistor R2F and a resistor R2G, the first end of the resistor R2E and the first end of the resistor R2F are connected to a first node, the first node is the input end of the sampling module, the second end of the resistor R2F, the second end of the resistor R2E, the first end of the resistor R2G and the first end of the resistor R2H are all connected to the same node, the second end of the resistor R2G and the second end of the resistor R2H are connected to a second node, and the second node is the output end of the sampling module.

[0015] Compared with the prior art, the utility model has the following beneficial effects:

[0016] The utility model provides a charger with input overvoltage protection, which includes a first transformer circuit, a sampling module, a PWM chip, and a driving circuit. The input end of the first transformer circuit is connected to the input end of the charger, and the output end of the first transformer circuit is the output end of the charger; the input end of the sampling module is connected to the input end of the first transformer circuit, the output end of the sampling module is connected to the signal input end of the PWM chip, the signal output end of the PWM chip is connected to the control end of the driving circuit, and the driving circuit is arranged at the input end of the first transformer circuit. In this way, the input voltage of the charger power supply end can be obtained through the sampling module, and the current actual input voltage can be compared with whether it exceeds a preset maximum value through the PWM chip. In the case of exceeding the maximum value, the switch MOS tube in the driving circuit is controlled to be turned off to disconnect the connection between the input end of the first transformer circuit and the input end of the charger. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 The utility model provides a schematic diagram of the structure of a charger with input overvoltage protection;

[0019] Figure 2 The utility model provides a structural schematic diagram of the connection between a PWM chip and an auxiliary power supply. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the solution of the utility model, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of 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.

[0021] See also Figure 1 A charger with input overvoltage protection, characterized in that it includes a first voltage conversion circuit, a sampling module, a PWM chip, and a driving circuit.

[0022] The input end of the first voltage conversion circuit is connected to the input end of the charger, and the output end of the first voltage conversion circuit is the output end of the charger;

[0023] The input end of the sampling module is connected to the input end of the first transformer circuit, the output end of the sampling module is connected to the signal input end of the PWM chip, the signal output end of the PWM chip is connected to the control end of the drive circuit, and the drive circuit is arranged at the input end of the first transformer circuit.

[0024] The precise input overvoltage point (such as 285V) can be pre-set in the PWM chip, and the input voltage can be synchronously detected when the charger is working. When the input voltage exceeds the preset overvoltage point (such as 285V), the PWM chip controls the drive circuit to stop driving and the charger stops working until the voltage drops to the rated value (which can be set), which effectively protects the charger from being burned by the high voltage generated by power grid fluctuations.

[0025] Optionally, the first transformer circuit includes a high-frequency transformer, a first rectifier, and a first filter. The input end of the high-frequency transformer is the input end of the first transformer circuit, the positive output end of the high-frequency transformer is connected to the input end of the first rectifier, the output end of the first rectifier is connected to the input end of the first filter, the output end of the first filter is the positive output end of the charger, and the negative output end of the high-frequency transformer is the negative output end of the charger.

[0026] When the charger is working normally, the PWM chip controls the duty cycle of the switching MOS tube, and the switching MOS tube controls the output and cutoff of the direct current transmitted to the first transformer circuit, thereby forming a rectangular wave transmitted to the high-frequency transformer. By turning on and off the high frequency of the switching MOS tube, a high-frequency rectangular wave is transmitted to the high-frequency transformer, thereby improving the efficiency of the frequency transformer and reducing the size of the charger. The high-frequency transformer enables the charger to output the direct current required for the charging battery through the first rectifier and the first filter.

[0027] Optional, see Figure 2 The structural schematic diagram of a PWM chip connected to an auxiliary power supply shown in the figure also includes an auxiliary power supply, a resistor R1, a diode D1, and a capacitor C1, wherein the positive electrode of the auxiliary power supply is connected to the first end of the resistor R1, the second end of the resistor R1 is connected to the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to the power supply end of the PWM chip, the positive electrode of the capacitor C1 is connected to the negative electrode of the diode D1, and the negative electrode of the capacitor C1 and the negative electrode of the auxiliary power supply are both grounded.

[0028] Exemplarily, the auxiliary power supply may be a transformer, and direct current of an amplitude required by the power supply end of the PWM chip may be obtained from the secondary winding of the transformer.

[0029] Optionally, the driving circuit includes a switch MOS tube, and the switch MOS tube is used to turn on or off the circuit at the input end of the first transformer circuit.

[0030] When the PWM chip detects that the voltage at the input end of the first transformer circuit is too high, it can control the switch MOS tube to turn off, thereby disconnecting the connection between the input end of the first transformer circuit and the input end of the charger, cutting off the transmission of excessively high voltage to the first transformer circuit and protecting the charger.

[0031] The input end of the charger of the present application can be powered by direct current, such as a battery, or can be powered by alternating current, such as a mains power supply.

[0032] In a possible implementation manner, an input terminal of the charger is connected to direct current.

[0033] The charger is powered by direct current.

[0034] In another possible implementation, the input end of the charger is connected to alternating current and also includes an AC / DC conversion circuit, the input end of the charger is connected to the input end of the AC / DC conversion circuit, and the output end of the AC / DC conversion circuit is connected to the input end of the first transformer circuit.

[0035] The charger is powered by AC power.

[0036] Exemplarily, the AC / DC conversion circuit includes a surge protector, an electromagnetic compatibility (EMC), a second rectifier, and a second filter. The surge protector is connected to alternating current, the output end of the surge protector is connected to the input end of the electromagnetic compatibility (EMC), the output end of the electromagnetic compatibility (EMC) is connected to the second rectifier, the output end of the second rectifier is connected to the input end of the second filter, and the output end of the second filter is connected to the input end of the first transformer circuit.

[0037] The second rectifier may be a silicon diode rectifier.

[0038] The sampling module mentioned above includes a battery pack, and the structure of the battery pack can be:

[0039] The sampling module includes a resistor R2E, a resistor R2H, a resistor R2F and a resistor R2G. The first end of the resistor R2E and the first end of the resistor R2F are connected to a first node, which is the input end of the sampling module. The second end of the resistor R2F, the second end of the resistor R2E, the first end of the resistor R2G and the first end of the resistor R2H are all connected to the same node. The second end of the resistor R2G and the second end of the resistor R2H are connected to a second node, which is the output end of the sampling module.

[0040] For example, the current actual voltage value can be determined based on the product of the actual current of the sampling module input to the PWM chip and the total resistance of the sampling module. The PWM chip compares the actual voltage value with the preset maximum voltage value. If the maximum value is exceeded, the switch tube in the drive circuit is turned off, and the connection between the input end of the first transformer circuit and the input end of the charger is disconnected, thereby cutting off the transmission of excessively high voltage to the first transformer circuit and protecting the charger.

[0041] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0042] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A charger with input overvoltage protection, characterized in that: It includes a first voltage conversion circuit, a sampling module, a PWM chip, and a driving circuit. The input end of the first voltage conversion circuit is connected to the input end of the charger, and the output end of the first voltage conversion circuit is the output end of the charger; The input end of the sampling module is connected to the input end of the first transformer circuit, the output end of the sampling module is connected to the signal input end of the PWM chip, the signal output end of the PWM chip is connected to the control end of the drive circuit, and the drive circuit is arranged at the input end of the first transformer circuit.

2. The charger according to claim 1, characterized in that: The first transformer circuit includes a high-frequency transformer, a first rectifier, and a first filter. The input end of the high-frequency transformer is the input end of the first transformer circuit, the positive output end of the high-frequency transformer is connected to the input end of the first rectifier, the output end of the first rectifier is connected to the input end of the first filter, the output end of the first filter is the positive output end of the charger, and the negative output end of the high-frequency transformer is the negative output end of the charger.

3. The charger according to claim 1, characterized in that: It also includes an auxiliary power supply, a resistor R1, a diode D1, and a capacitor C1. The positive electrode of the auxiliary power supply is connected to the first end of the resistor R1, the second end of the resistor R1 is connected to the positive electrode of the diode D1, the negative electrode of the diode D1 is connected to the power supply end of the PWM chip, the positive electrode of the capacitor C1 is connected to the negative electrode of the diode D1, and the negative electrode of the capacitor C1 and the negative electrode of the auxiliary power supply are both grounded.

4. The charger according to claim 1, characterized in that: The driving circuit includes a switch MOS tube, and the switch MOS tube is used to turn on or off the circuit at the input end of the first voltage conversion circuit.

5. The charger according to claim 1, characterized in that: The input end of the charger is connected to direct current.

6. The charger according to claim 1, characterized in that: The input end of the charger is connected to alternating current, and also includes an AC / DC conversion circuit. The input end of the charger is connected to the input end of the AC / DC conversion circuit, and the output end of the AC / DC conversion circuit is connected to the input end of the first transformer circuit.

7. The charger according to claim 6, characterized in that: The AC / DC conversion circuit includes a surge protector, an electromagnetic compatibility (EMC), a second rectifier, and a second filter. The surge protector is connected to alternating current, the output end of the surge protector is connected to the input end of the electromagnetic compatibility (EMC), the output end of the electromagnetic compatibility (EMC) is connected to the second rectifier, the output end of the second rectifier is connected to the input end of the second filter, and the output end of the second filter is connected to the input end of the first transformer circuit.

8. The charger according to claim 1, characterized in that: The sampling module includes a resistor R2E, a resistor R2H, a resistor R2F and a resistor R2G. The first end of the resistor R2E and the first end of the resistor R2F are connected to a first node, which is the input end of the sampling module. The second end of the resistor R2F, the second end of the resistor R2E, the first end of the resistor R2G and the first end of the resistor R2H are all connected to the same node. The second end of the resistor R2G and the second end of the resistor R2H are connected to a second node, which is the output end of the sampling module.

Images