CN217935135U

CN217935135U - Self-slow charging circuit

Info

Publication number: CN217935135U
Application number: CN202221630500.XU
Authority: CN
Inventors: 李敬恩; 刘美堂; 刘士军; 杜荣辉; 马英华
Original assignee: Shandong Longertek Technology Co Ltd
Current assignee: Shandong Longertek Technology Co Ltd
Priority date: 2022-06-27
Filing date: 2022-06-27
Publication date: 2022-11-29
Anticipated expiration: 2032-06-27

Abstract

The utility model relates to a self-slow charging circuit, which comprises a loop formed by connecting a power supply anode, a cathode, an electrolytic capacitor and an IGBT in series, and also comprises a voltage division circuit connected between a power supply circuit and an IGBT grid electrode and used for controlling the IGBT to be in a linear amplification state; the voltage detection circuit is used for detecting the voltage of the IGBT collector electrode and the emitter electrode, and the output end of the voltage detection circuit is connected with the voltage detection end of the IGBT drive circuit; and the IGBT driving circuit is used for controlling the voltage output end to supply power to the IGBT when the IGBT collector-emitter voltage is lower than a threshold value, so that the IGBT is converted into a conducting state from a linear amplification state. The utility model discloses can realize automatic switch-over IGBT operating condition and need not external control signal, need not MCU or controller promptly, can accomplish buffer function automatically, use conveniently, occupy small, do benefit to compact design.

Description

Self-slow charging circuit

Technical Field

The utility model relates to a charging circuit, in particular to from slow charging circuit.

Background

The voltage of an electrolytic capacitor in the power electronic converter is close to zero in an initial state, and when a system is powered on, the load is allowed to work normally after the voltage of the electrolytic capacitor needs to reach a value meeting the requirement. The existing methods mainly comprise the following two methods:

1. as shown in fig. 1, a method of connecting a resistor in parallel to a relay. When the voltage of the direct current bus is lower, the relay keeps an off state because of receiving an off control signal from the MCU, and the current is limited by the resistor to charge the electrolytic capacitor. When the voltage of the direct current bus is higher, the relay keeps the attraction state because of receiving an attraction control signal from the MCU, the resistor is bypassed, the charging loop is low in impedance, and the load is allowed to work normally.

2. As shown in fig. 2, a method of connecting thyristors in parallel with resistors. When the voltage of the direct current bus is low, the controllable silicon keeps a disconnected state because the controllable silicon does not receive any control signal from the MCU, and the current is limited by the resistor to charge the capacitor, so that the voltage of the capacitor is continuously increased. When the capacitor voltage is higher, the controllable silicon is conducted due to the fact that the controllable silicon receives the conducting control signal from the MCU, the conducting state is maintained, the resistor is bypassed, the charging loop is low in impedance, and the load is allowed to work normally.

The prior art mainly has the following defects:

(1) The control method of the relay has the following defects: the active turn-off can be realized only by a control signal from the MCU, a driving circuit needs to be designed for the relay, and the relay occupies a large space in equipment and is not beneficial to compact design. The relay has higher cost and short service life.

(2) And the silicon controlled rectifier control method has the following defects: the active switch-off can be realized only by a control signal from the MCU, the drive current of the controllable silicon is very large, and the design of a drive circuit is difficult.

(3) The two methods both need resistors, and the resistors require large power and occupy large volume, which is not favorable for compact design.

In order to solve the technical problem, other patent applications such as chinese patent application with application number CN201910467526.3, named as a precharge circuit of a high-power BOOST voltage-boosting circuit, disclose: the pre-charging unit comprises an IGBT, and the IGBT is connected with an input battery, an inductor L, a parasitic resistor R of the inductor L, a diode D and a capacitor C in series to form a loop; the IGBT and the capacitor C are in the same branch and are connected with the output voltage in parallel. Precharge the drive unit including power supply, first divider resistance R1, second divider resistance R2, the third divider resistance R3 that establishes ties in proper order, still include darlington pipe VT, darlington pipe VT is parallelly connected with second divider resistance R2T, and third divider resistance R3's high-pressure end links to each other with IGBT's control gate port. The pre-charging driving unit further comprises a photoelectric isolator and a current-limiting resistor R4, the photoelectric isolator is connected with a power supply through the current-limiting resistor R4, and the output end of the photoelectric isolator is connected with the port of the control gate of the Darlington tube VT. The patent application still has the problems that an MCU needs to be arranged, compact design cannot be achieved, and the like.

SUMMERY OF THE UTILITY MODEL

The main objective of the present invention is to solve the above technical problem, and to provide a self-slow charging circuit with low cost and small occupied volume.

In order to achieve the above purpose, the technical scheme of the utility model is that:

a self-slow charging circuit comprises a loop formed by connecting a power supply anode, a cathode, an electrolytic capacitor and an IGBT in series, and further comprises a voltage division circuit connected between a power supply circuit and an IGBT grid and used for controlling the IGBT to be in a linear amplification state;

the voltage detection circuit is used for detecting the voltage of the IGBT collector electrode and the emitter electrode, and the output end of the voltage detection circuit is connected with the voltage detection end of the IGBT drive circuit;

and the IGBT driving circuit is used for controlling the voltage output end to supply power to the IGBT when the voltage of the collector electrode and the emitter electrode of the IGBT is lower than a threshold value, so that the IGBT is converted into a conducting state from a linear amplification state.

Further, the power supply circuit comprises a resistor R1, a voltage stabilizing diode ZD1 and a capacitor C3, one end of the resistor R1 is connected with the positive electrode of the power supply, the other end of the resistor R1 is connected with the cathode of the voltage stabilizing diode ZD1, the anode of the voltage stabilizing diode ZD1 is connected with the negative electrode of the power supply, and the capacitor C3 is connected with the voltage stabilizing diode ZD1 in parallel.

Further, the voltage division circuit comprises a resistor R7 and a resistor R9, one end of the resistor R7 is connected with the power supply circuit, the other end of the resistor R7 is connected with the grid electrode of the IGBT, and the resistor R9 is connected with the grid electrode and the emitting electrode of the IGBT in parallel.

Further, the voltage detection circuit comprises a resistor R3 and a resistor R4, and the resistor R3 and the resistor R4 are connected in series and then connected in parallel with the grid electrode and the emitter electrode of the IGBT.

Further, the IGBT driving circuit comprises an integrated circuit IC, a resistor R6 and a diode D1, wherein a voltage output end of the integrated circuit IC is connected with the resistor R6 and the diode D1 in series, and a cathode of the diode D1 is connected with a grid electrode of the IGBT.

Further, the IGBT power supply also comprises a soft turn-off circuit which is used for conducting when the current exceeds a normal range and controlling the collector current of the IGBT to slowly fall;

the soft turn-off circuit is connected with the grid electrode and the emitting electrode of the IGBT in parallel.

Further, the soft turn-off circuit comprises a resistor R10 and a triode Q2, the fault output end of the IGBT driving circuit is connected with one end of the resistor R10, the other end of the resistor R10 is connected with the base electrode of the triode Q2, and the collector electrode and the emitter electrode of the triode Q2 are connected with the grid electrode and the emitter electrode of the IGBT in parallel.

Further, the IGBT driving circuit further comprises a resistor R11, the resistor R11 is connected with a collector-emitter of the IGBT in series, and one end of the resistor R11 is connected with a current/voltage signal detection end of the IGBT driving circuit.

Further, the IGBT driving circuit is used for outputting voltage at the fault output end and reducing the voltage at the voltage output end when the voltage value of the resistor R11 is larger than a threshold value.

In conclusion, the utility model provides a from slow charging circuit, can realize automatic switch IGBT operating condition and do not need external control signal, need not MCU or controller promptly, can accomplish buffer function automatically, use the convenience, occupy small, do benefit to compact design.

Drawings

FIG. 1 is a schematic diagram of the prior art;

FIG. 2 is a schematic diagram of the prior art;

fig. 3 is a schematic diagram of the present invention.

Detailed Description

The present invention will be described in further detail with reference to the following detailed description and accompanying drawings:

in order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

A self-slow charging circuit mainly comprises a loop formed by connecting a positive pole DC +, a negative pole DC-, an electrolytic capacitor E1 and an IGBTQ3 of a power supply in series. The power supply circuit, the voltage division circuit, the voltage detection circuit, the IGBT driving circuit and the soft turn-off circuit are further included.

The power supply circuit is used for providing power for the operation of the components. The voltage division circuit is connected between the power supply circuit and the IGBT grid and used for controlling the IGBT to be in a linear amplification state. The voltage detection circuit is used for detecting the voltage of the collector electrode and the emitter electrode of the IGBT, and the output end of the voltage detection circuit is connected with the voltage detection end of the IGBT driving circuit. The IGBT driving circuit is used for controlling the voltage output end to supply power to the IGBT when the voltage of the collector electrode and the emitter electrode of the IGBT is lower than a threshold value, so that the IGBT is converted into a conducting state from a linear amplification state. The soft turn-off circuit is used for controlling the current of the collector of the IGBT to slowly drop when overcurrent protection occurs, so that the IGBT is turned off at a safer speed, the breakdown of the collector due to overhigh voltage peak caused by overhigh di and dt is prevented, and the soft turn-off circuit is connected with the grid and the emitter of the IGBT in parallel.

Specifically, the power supply circuit comprises a resistor R1, a voltage stabilizing diode ZD1 and a capacitor C3, wherein one end of the resistor R1 is connected with the positive electrode of a power supply, the other end of the resistor R1 is connected with the cathode of the voltage stabilizing diode ZD1, the anode of the voltage stabilizing diode ZD1 is connected with the negative electrode of the power supply, and the capacitor C3 is connected with the voltage stabilizing diode ZD1 in parallel.

The voltage division circuit comprises a resistor R7 and a resistor R9, one end of the resistor R7 is connected with the power supply circuit, the other end of the resistor R7 is connected with the grid electrode of the IGBT, and the resistor R9 is connected with the grid electrode and the emitting electrode of the IGBT in parallel.

The voltage detection circuit comprises a resistor R3 and a resistor R4, wherein the resistor R3 and the resistor R4 are connected in series and then are connected in parallel with a grid electrode and an emitting electrode of the IGBT.

The IGBT driving circuit comprises an integrated circuit IC, a resistor R6 and a diode D1, wherein the voltage output end of the integrated circuit IC is connected with the resistor R6 and the diode D1 in series, and the cathode of the diode D1 is connected with the grid of the IGBT. The integrated circuit IC has 8 pins, of which pin 1 functions to detect the current/voltage signal, causing the 5 pin output to go low and the 7 pin output to go high when the threshold is reached. The 2-pin function is ground referenced to a 5-pin voltage. The 3-pin function is the ground reference for the 6-pin power supply. The 4-pin function is voltage detection, when the voltage signal is higher than a threshold value, the 5-pin output is low, and when the voltage signal is lower than the threshold value, the 5-pin output is high. The pin 5 is the voltage output, and the output voltage is determined by the pin 1, the pin 7 and the pin 5 together. The 6 pins are power pins for supplying power to the integrated circuit IC. Pin 7 is a fault output pin, and the output voltage is determined by pin 1. The 8-pin function is fault blanking, a capacitor is connected between the 8-pin and the 3-pin, and the capacity of the capacitor determines the time interval for shielding faults.

When the initial voltage value of the electrolytic capacitor E1 is 0V (or a lower voltage value), the switch S1 is closed, and the VCC voltage does not reach the normal working voltage of the integrated circuit IC immediately. The voltage output terminal (pin 5) of the integrated circuit IC outputs 0V. Due to the voltage dividing effect of the resistor R7 and the resistor R9, the gate voltage Vg = R9/(R7 + R9) of the IGBT, so the gate voltage Vg of the IGBT gradually rises as the VCC voltage gradually rises, and the IGBT always operates in a linear amplification state while the gate voltage Vg of the IGBT rises, and the collector current is determined by the gate voltage Vg, so the current flowing through the collector of the IGBT also gradually increases. Until the VCC voltage rises to 16V, the voltage will not rise any more, vg is maintained at 8V, and the collector current of the control IGBT remains unchanged. The collector current charges the electrolytic capacitor E1, so that the voltage of the electrolytic capacitor E1 gradually rises, the collector-emitter voltage Vce of the IGBT gradually decreases, when the voltage detection end (pin 4) of the integrated circuit IC detects that the voltage of the collector-emitter voltage Vce falls to a threshold value, the output voltage of the voltage output end (pin 5) of the integrated circuit IC is changed from 0V to 16V, and the IGBT grid electrode is charged through the resistor R6 and the diode D1, because the resistance value of the resistor R6 is small, the grid voltage Vg of the IGBT rapidly rises to about 15V, the IGBT enters a saturation conduction state, and the magnitude of the collector current is determined by the load.

The voltage detection circuit is used for monitoring the voltage Vce of the collector electrode and the emitter electrode, when the voltage is higher than a set value, the IGBT is in a linear area, and when the voltage is lower than the set value, the IGBT is in saturated conduction, so that the working state of the IGBT is automatically switched, an external control signal is not needed, namely an MCU or a controller is not needed, the buffer function can be automatically completed, the application is convenient, the occupied volume is small, and the compact design is facilitated.

The soft turn-off circuit comprises a resistor R10 and a triode Q2, the fault output end of the IGBT driving circuit is connected with one end of the resistor R10, the other end of the resistor R10 is connected with the base electrode of the triode Q2, and the collector electrode and the emitter electrode of the triode Q2 are connected with the grid electrode and the emitter electrode of the IGBT in parallel.

The IGBT driving circuit further comprises a resistor R11, the resistor R11 is connected with a collector-emitter of the IGBT in series, and one end of the resistor R11 is connected with a current/voltage signal detection end of the IGBT driving circuit, namely a pin 1 of the integrated circuit IC. When the voltage value of the resistor R11 is greater than the threshold value, the fail output terminal outputs the voltage and lowers the voltage output terminal voltage even if the 5-pin output becomes low and the 7-pin output becomes high.

When the current is in a normal range, the voltage of the R11 is smaller than the trigger threshold of the OC pin (pin 1), so that the FLT pin (pin 7) outputs low level, the triode Q2 is in a cut-off state, and the IGBT is not influenced. When the current exceeds the normal range, the voltage of R11 is greater than the trigger threshold of OC foot (1 foot), FLT foot (7 feet) output 15V, the base-emitter of triode Q2 has the current to pass through, triode Q2 switches on, but because resistance R10 is great, the collector current of triode Q2 is not very big, so the grid voltage of IGBT can slowly descend, control IGBT's collector current slowly to descend, realized overcurrent protection's soft shutoff, effectual improvement circuit reliability.

A from slow charging circuit, can realize automatic switch-over IGBT operating condition and do not need external control signal, need not MCU or controller promptly, can accomplish buffer function automatically, it is convenient to use, occupies smallly, does benefit to compact design.

Similar solutions can be derived as described above in connection with the solution contents given in the figures. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention are still within the scope of the technical solution of the present invention unless departing from the content of the technical solution of the present invention.

Claims

1. The utility model provides a from slow charging circuit, includes the return circuit that constitutes by the anodal, negative pole, electrolytic capacitor, IGBT series connection of power, its characterized in that: the voltage division circuit is connected between the power supply circuit and the IGBT grid and used for controlling the IGBT to be in a linear amplification state;

2. A self-buffering charging circuit as claimed in claim 1, wherein: the power supply circuit comprises a resistor R1, a voltage stabilizing diode ZD1 and a capacitor C3, wherein one end of the resistor R1 is connected with the positive electrode of a power supply, the other end of the resistor R1 is connected with the cathode of the voltage stabilizing diode ZD1, the anode of the voltage stabilizing diode ZD1 is connected with the negative electrode of the power supply, and the capacitor C3 is connected with the voltage stabilizing diode ZD1 in parallel.

3. A self-buffering charging circuit as claimed in claim 1, wherein: the voltage division circuit comprises a resistor R7 and a resistor R9, one end of the resistor R7 is connected with the power supply circuit, the other end of the resistor R7 is connected with the grid electrode of the IGBT, and the resistor R9 is connected with the grid electrode and the emitting electrode of the IGBT in parallel.

4. A self-buffering charging circuit as claimed in claim 1, wherein: the voltage detection circuit comprises a resistor R3 and a resistor R4, wherein the resistor R3 and the resistor R4 are connected in series and then are connected in parallel with a grid electrode and an emitting electrode of the IGBT.

5. A self-buffering charging circuit as claimed in claim 1, wherein: the IGBT driving circuit comprises an integrated circuit IC, a resistor R6 and a diode D1, wherein the voltage output end of the integrated circuit IC is connected with the resistor R6 and the diode D1 in series, and the cathode of the diode D1 is connected with the grid of the IGBT.

6. A self-buffering charging circuit as claimed in claim 1, wherein: the soft turn-off circuit is used for conducting when the current exceeds a normal range and controlling the current of the collector of the IGBT to slowly fall;

7. A self-buffering charging circuit according to claim 6, wherein: the soft turn-off circuit comprises a resistor R10 and a triode Q2, the fault output end of the IGBT driving circuit is connected with one end of the resistor R10, the other end of the resistor R10 is connected with the base electrode of the triode Q2, and the collector electrode and the emitter electrode of the triode Q2 are connected with the grid electrode and the emitter electrode of the IGBT in parallel.

8. A self-buffering charging circuit according to claim 7, wherein: the IGBT driving circuit further comprises a resistor R11, the resistor R11 is connected with a collector-emitter of the IGBT in series, and one end of the resistor R11 is connected with a current/voltage signal detection end of the IGBT driving circuit.

9. A self-buffering charging circuit as claimed in claim 8, wherein: and the IGBT driving circuit is used for outputting voltage at the fault output end and reducing the voltage at the voltage output end when the voltage value of the resistor R11 is larger than the threshold value.