Rectifier tube quick turn-off circuit of efficient CRM totem pole

Abstract

The utility model relates to a high-efficiency CRM totem pole rectifier tube fast turn-off circuit, which is used for controlling fast turn-off of a rectifier tube, a first current transformer CT1 and a second current transformer CT2 are used for current sampling when the circuit works normally, the current directions are opposite when the circuit is abnormal, and the current sampling time is short. The first current transformer CT1 and the second current transformer CT2 cannot detect abnormal large current, so that the third current transformer CT3 and the fourth current transformer CT4 are additionally arranged in the circuit, the third current transformer CT3 and the first current transformer CT1 are reversely connected in series, and the fourth current transformer CT4 and the second current transformer CT2 are connected in series. The third current transformer CT3 and the fourth current transformer CT4 are connected in series in a reverse direction, the fourth current transformer CT4 and the second current transformer CT2 are connected in series in a reverse direction, and the third current transformer CT3 and the fourth current transformer CT4 can transmit a sampling signal of a reverse large current to a COMP comparator module of the control chip MCU, so that the control chip MCU rapidly turns off a related rectifier tube, and an effective protection effect is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply equipment, in particular to a rectifier tube fast shut-down circuit of a high-efficiency CRM totem pole. Background Art

[0002] With the rapid development of society, electronic technology has been widely used in various fields, and the types of electronic equipment are increasing. Electronic equipment cannot do without the support of power supply, and the quality requirements of power supply are getting higher and higher. It is hoped that power supply equipment with high efficiency, no grid pollution, and no electromagnetic interference is obtained. In the PFC (Power Factor Correction) part of the power supply, the CRM totem pole PFC circuit with rectifier tube is used, which has the advantages of simple circuit, low cost and high efficiency.

[0003] At present, in this kind of high-efficiency CRM totem pole PFC circuit with rectifier tube, the common method to determine whether the rectifier tube is turned off is to detect the amplitude of the input voltage and shut down when the input voltage amplitude reaches a predetermined value. If this shutdown method is used, when the input power is off or lightning strikes, and the rectifier tube needs to be quickly shut down, the input voltage needs to be processed through a series of processes such as sampling and calculation before the shutdown signal can be output. Therefore, the components will be damaged due to untimely shutdown. Utility Model Content

[0004] In view of this, it is necessary to provide a high-efficiency CRM totem pole rectifier tube fast shutdown circuit with fast signal detection speed and simple circuit structure.

[0005] A high-efficiency CRM totem pole rectifier tube fast shutdown circuit is used to control the fast shutdown of the rectifier tube, comprising a fast switching circuit and a control chip MCU, wherein the fast switching circuit comprises a totem pole circuit and a current sampling circuit, wherein the input end of the totem pole circuit is connected to an alternating current power supply AC, and the output end of the totem pole circuit is connected to a load circuit; the totem pole circuit has multiple groups of rectifier tubes, and the current sampling circuit is used to collect the current of each group of rectifier tubes; the current sampling circuit transmits the collected current value of each group of rectifier tubes to the control chip MCU, and the control chip MCU controls the rectifier tube to be quickly shut down in a critical continuous mode according to the sampled current value, so as to protect the rectifier tube.

[0006] Preferably, the totem pole circuit includes a first rectifier tube S1, a second rectifier tube S2, a third rectifier tube S3, a fourth rectifier tube S4, a first inductor L1 and a second capacitor C2, the first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4 form a rectifier bridge circuit, the input end of the rectifier bridge circuit is connected to the AC power supply AC through the first inductor L1, and the output end of the rectifier bridge circuit is connected to the load circuit through the second capacitor C2; the gates of the first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4 are respectively connected to the EPWM signal control end of the control chip MCU, and the output EPWM signal of the control chip MCU is used to control the conduction and shutdown of the first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4.

[0007] Preferably, the current sampling circuit includes a first current transformer CT1, a second current transformer CT2, a third current transformer CT3 and a fourth current transformer CT4; the P2 end of the first current transformer CT1 is connected to the P2 end of the third current transformer CT3, and the P1 end of the third current transformer CT3 is intercepted to the drain of the first rectifier S1; the P1 end of the fourth current transformer CT4 is connected to the P1 end of the second current transformer CT2, the P2 end of the second current transformer CT2 is connected to the drain of the second rectifier S2, and the source of the second rectifier S2 is connected to the first current transformer CT 1, and then connected to the positive electrode of the AC power source AC through the first inductor L1; the P2 end of the fourth current transformer CT4 is connected to the drain of the fourth rectifier S4, and the source of the fourth rectifier S4 is connected to the drain of the third rectifier S3, and then connected to the negative electrode of the AC power source AC; the source of the third rectifier S3 is connected to the source of the first rectifier S1; the two ends of the second capacitor C2 are respectively connected to the connection point between the P2 end of the fourth current transformer CT4 and the drain of the fourth rectifier S4 and the connection point between the source of the first rectifier S1 and the source of the third rectifier S3.

[0008] Preferably, the positive and negative poles of the AC power supply AC, the current sampling signal output ends of the first current transformer CT1 and the second current transformer CT2 are respectively connected to the ADC analog-to-digital conversion input end of the control chip MCU; the current sampling signal output ends of the third current transformer CT3 and the fourth current transformer CT4 are respectively connected to the COMP comparator module input end of the control chip MCU.

[0009] In the rectifier tube fast shutdown circuit of the above-mentioned high-efficiency CRM totem pole, the first current transformer CT1 and the second current transformer CT2 are used for current sampling when the circuit is working normally, and the current direction is opposite when the circuit is abnormal. The first current transformer CT1 and the second current transformer CT2 cannot detect abnormally large currents, so the third current transformer CT3 and the fourth current transformer CT4 are added to the circuit, wherein the third current transformer CT3 is reversely connected in series with the first current transformer CT1, and the fourth current transformer CT4 is reversely connected in series with the second current transformer CT2. The third current transformer CT3 and the fourth current transformer CT4 can transmit the sampling signal of the reverse large current to the COMP comparator module of the control chip MCU, so that the control chip MCU quickly shuts off the relevant rectifier tube, thereby playing an effective protective role. The circuit structure of the utility model is simple, easy to implement, low cost, and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a circuit structure schematic diagram of a rectifier tube fast shutdown circuit of a high-efficiency CRM totem pole according to an embodiment of the utility model.

[0011] Figure 2 It is a schematic diagram of the forward working charging process of the high-efficiency CRM totem pole PFC of the rectifier tube fast shutdown circuit of the high-efficiency CRM totem pole in the embodiment of the utility model.

[0012] Figure 3 It is a schematic diagram of driving a high-efficiency CRM totem pole PFC rectifier tube of a high-efficiency CRM totem pole rectifier tube fast shutdown circuit according to an embodiment of the utility model.

[0013] Figure 4 It is a schematic diagram of driving the rectifier tube when the input voltage of the high-efficiency CRM totem pole PFC of the high-efficiency CRM totem pole rectifier tube fast shutdown circuit is abnormal in the forward direction of the embodiment of the utility model.

[0014] Figure 5 It is a schematic diagram of short-circuit current when the input voltage of the high-efficiency CRM totem pole PFC of the high-efficiency CRM totem pole rectifier tube fast shutdown circuit of the utility model embodiment is abnormal in forward operation.

[0015] Figure 6 It is a schematic diagram of the negative working charging process of the efficient CRM totem pole PFC of the rectifier tube fast shutdown circuit of the efficient CRM totem pole in the embodiment of the utility model.

[0016] Figure 7 It is a schematic diagram of driving the rectifier tube when the input voltage of the efficient CRM totem pole PFC of the efficient CRM totem pole rectifier tube fast shutdown circuit of the utility model embodiment is abnormal in the negative direction.

[0017] Figure 8 It is a schematic diagram of short-circuit current when the input voltage of the efficient CRM totem pole PFC of the efficient CRM totem pole rectifier tube fast shutdown circuit of the utility model embodiment is abnormally working in the negative direction. DETAILED DESCRIPTION

[0018] The present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0019] See also Figure 1 , showing a high-efficiency CRM totem pole rectifier tube fast shutdown circuit, which is used to control the fast shutdown of the rectifier tube, including a fast switching circuit and a control chip MCU, the fast switching circuit including a totem pole circuit and a current sampling circuit, the input end of the totem pole circuit is connected to an alternating current power supply AC, and the output end of the totem pole circuit is connected to a load circuit; the totem pole circuit has multiple groups of rectifier tubes, and the current sampling circuit is used to collect the current of each group of rectifier tubes; the current sampling circuit transmits the collected current value of each group of rectifier tubes to the control chip MCU, and the control chip MCU controls the rectifier tube to be quickly shut down in the critical continuous mode according to the sampled current value to protect the rectifier tube.

[0020] Preferably, the totem pole circuit includes a first rectifier tube S1, a second rectifier tube S2, a third rectifier tube S3, a fourth rectifier tube S4, a first inductor L1 and a second capacitor C2, the first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4 form a rectifier bridge circuit, the input end of the rectifier bridge circuit is connected to the AC power supply AC through the first inductor L1, and the output end of the rectifier bridge circuit is connected to the load circuit through the second capacitor C2; the gates of the first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4 are respectively connected to the EPWM signal control end of the control chip MCU, and the output EPWM signal of the control chip MCU is used to control the conduction and shutdown of the first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4.

[0021] Preferably, the current sampling circuit includes a first current transformer CT1, a second current transformer CT2, a third current transformer CT3 and a fourth current transformer CT4; the P2 end of the first current transformer CT1 is connected to the P2 end of the third current transformer CT3, and the P1 end of the third current transformer CT3 is intercepted to the drain of the first rectifier S1; the P1 end of the fourth current transformer CT4 is connected to the P1 end of the second current transformer CT2, the P2 end of the second current transformer CT2 is connected to the drain of the second rectifier S2, and the source of the second rectifier S2 is connected to the first current transformer CT 1, and then connected to the positive electrode of the AC power source AC through the first inductor L1; the P2 end of the fourth current transformer CT4 is connected to the drain of the fourth rectifier S4, and the source of the fourth rectifier S4 is connected to the drain of the third rectifier S3, and then connected to the negative electrode of the AC power source AC; the source of the third rectifier S3 is connected to the source of the first rectifier S1; the two ends of the second capacitor C2 are respectively connected to the connection point between the P2 end of the fourth current transformer CT4 and the drain of the fourth rectifier S4 and the connection point between the source of the first rectifier S1 and the source of the third rectifier S3.

[0022] Specifically, the second capacitor C2 plays a filtering role to filter out the AC component in the output voltage.

[0023] Preferably, the positive and negative poles of the AC power supply AC, the current sampling signal output ends of the first current transformer CT1 and the second current transformer CT2 are respectively connected to the ADC analog-to-digital conversion input end of the control chip MCU; the current sampling signal output ends of the third current transformer CT3 and the fourth current transformer CT4 are respectively connected to the COMP comparator module input end of the control chip MCU.

[0024] See also Figure 2 , Figure 3 , Figure 4 and Figure 5 , showing the current schematic diagram of the rectifier tube drive and abnormal short circuit when an abnormally large current appears during the forward charging process of the high-efficiency CRM totem pole PFC.

[0025] During the positive half cycle of the totem pole PFC circuit, Figure 2 As shown, the AC power source AC is powered by the first inductor L1, the first rectifier S1 is turned on, and the third rectifier S3 is turned on. The on and off of the rectifier tubes change with the direction of the input voltage, as shown in FIG. Figure 3 When conducting lightning strike or power failure experiments, the AC power source will switch from positive to negative, such as Figure 4As shown in FIG. 1 , within time T, the AC has been switched, but because the control chip MCU has not detected the output voltage switching, the third rectifier tube S3, which should be turned off, remains on. This will cause a short circuit by directly connecting the AC power source AC to the ground. Figure 5 As shown, the third rectifier tube S3 is damaged.

[0026] Since the current transformer CT can sense only the current flowing from the P1 terminal to the P2 terminal, the first current transformer CT1 and the second current transformer CT2 are used to sample the current during normal operation for loop control. When the circuit is abnormal, the direction of the current is opposite to that of the normal state. Figure 5 As shown, the first current transformer CT1 and the second current transformer CT2 cannot detect the large current when the circuit is abnormal. Therefore, two current transformers are connected in series in the circuit: the third current transformer CT3 and the fourth current transformer CT4, and the P2 end of the first current transformer CT1 is connected to the P2 end of the third current transformer CT3, and the P1 end of the second current transformer CT2 is connected to the P1 end of the fourth current transformer CT4, so as to ensure that the large current passing through the third current transformer CT3 and the fourth current transformer CT4 can be obtained when an abnormality occurs. The high current signals sensed by the third current transformer CT3 and the fourth current transformer CT4 are respectively connected to the COMP comparator module of the control chip MCU. Because the detection speed of the peripherals of the comparator module is determined by the frequency division of the main frequency of the control chip MCU, the detection speed of the peripherals of the comparator module can reach the microsecond or even nanosecond level. In the commonly used voltage detection method, due to the input voltage frequency, we need to perform multiple cycles of sampling to obtain a more accurate voltage value, which will result in a long sampling time, at least in milliseconds. Therefore, by connecting the high current to the comparator module for protection, the rectifier tube can be quickly shut down, thereby playing an effective protective role.

[0027] See also Figure 6 , Figure 7 and Figure 8 , showing the current schematic diagram of the rectifier tube drive and abnormal short circuit when an abnormally large current appears during the negative working charging process of the high-efficiency CRM totem pole PFC.

[0028] Due to the symmetry of the circuit, the working process of the positive and negative half-cycles of the totem pole PFC circuit is similar, and the working process of the negative half-cycle will not be repeated.

[0029] In the rectifier tube fast shutdown circuit of the above-mentioned high-efficiency CRM totem pole, the first current transformer CT1 and the second current transformer CT2 are used for current sampling when the circuit is working normally, and the current direction is opposite when the circuit is abnormal. The first current transformer CT1 and the second current transformer CT2 cannot detect abnormally large currents, so the third current transformer CT3 and the fourth current transformer CT4 are added to the circuit, wherein the third current transformer CT3 is reversely connected in series with the first current transformer CT1, and the fourth current transformer CT4 is reversely connected in series with the second current transformer CT2. The third current transformer CT3 and the fourth current transformer CT4 can transmit the sampling signal of the reverse large current to the COMP comparator module of the control chip MCU, so that the control chip MCU quickly shuts off the relevant rectifier tube, thereby playing an effective protective role. The circuit structure of the utility model is simple, easy to implement, low cost, and easy to promote.

[0030] It should be noted that the present invention is not limited to the above-mentioned embodiments. According to the creative spirit of the present invention, technical personnel in this field can also make other changes. These changes made according to the creative spirit of the present invention should be included in the scope of protection required by the present invention.

Claims

1. A high-efficiency CRM totem pole rectifier tube fast shutdown circuit, used to control the fast shutdown of the rectifier tube, characterized in that: It comprises a fast switching circuit and a control chip MCU, wherein the fast switching circuit comprises a totem pole circuit and a current sampling circuit, wherein the input end of the totem pole circuit is connected to an alternating current power supply AC, and the output end of the totem pole circuit is connected to a load circuit; the totem pole circuit has multiple groups of rectifier tubes, and the current sampling circuit is used to collect the current of each group of rectifier tubes; the current sampling circuit transmits the collected current value of each group of rectifier tubes to the control chip MCU, and the control chip MCU controls the rectifier tube to be quickly shut down in a critical continuous mode according to the sampled current value, so as to protect the rectifier tube.

2. The high-efficiency CRM totem pole rectifier tube fast shutdown circuit as claimed in claim 1, characterized in that: The totem pole circuit includes a first rectifier tube S1, a second rectifier tube S2, a third rectifier tube S3, a fourth rectifier tube S4, a first inductor L1 and a second capacitor C2. The first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4 form a rectifier bridge circuit. The input end of the rectifier bridge circuit is connected to the AC power supply AC through the first inductor L1, and the output end of the rectifier bridge circuit is connected to the load circuit through the second capacitor C2; the gates of the first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4 are respectively connected to the EPWM signal control end of the control chip MCU, and the output EPWM signal of the control chip MCU is used to control the conduction and shutdown of the first rectifier tube S1, the second rectifier tube S2, the third rectifier tube S3 and the fourth rectifier tube S4.

3. The high-efficiency CRM totem pole rectifier tube fast shutdown circuit as claimed in claim 2, characterized in that: The current sampling circuit includes a first current transformer CT1, a second current transformer CT2, a third current transformer CT3 and a fourth current transformer CT4; the P2 end of the first current transformer CT1 is connected to the P2 end of the third current transformer CT3, and the P1 end of the third current transformer CT3 is connected to the drain of the first rectifier S1; the P1 end of the fourth current transformer CT4 is connected to the P1 end of the second current transformer CT2, the P2 end of the second current transformer CT2 is connected to the drain of the second rectifier S2, and the source of the second rectifier S2 is connected to the drain of the first current transformer CT1. After being connected to the P1 end, it is connected to the positive electrode of the AC power supply AC through the first inductor L1; the P2 end of the fourth current transformer CT4 is connected to the drain of the fourth rectifier S4, and the source of the fourth rectifier S4 is connected to the drain of the third rectifier S3 and then connected to the negative electrode of the AC power supply AC; the source of the third rectifier S3 is connected to the source of the first rectifier S1; the two ends of the second capacitor C2 are respectively connected to the connection point between the P2 end of the fourth current transformer CT4 and the drain of the fourth rectifier S4 and the connection point between the source of the first rectifier S1 and the source of the third rectifier S3.

4. The high-efficiency CRM totem pole rectifier tube fast shutdown circuit as claimed in claim 3, characterized in that: The positive and negative poles of the AC power supply AC, the current sampling signal output ends of the first current transformer CT1 and the second current transformer CT2 are respectively connected to the ADC analog-to-digital conversion input end of the control chip MCU; the current sampling signal output ends of the third current transformer CT3 and the fourth current transformer CT4 are respectively connected to the COMP comparator module input end of the control chip MCU.

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