A redundant dual pre-charging circuit for MOS tubes with staggered gate drive

Abstract

The utility model provides a gate staggered driving MOS tube redundant double pre-charging circuit, the drain of MOS tube Q1 is connected to the source of MOS tube Q2, any point A is taken between the drain of MOS tube Q1 and the source of MOS tube Q2, the drain of MOS tube Q3 is connected to the source of MOS tube Q4, any point B is taken between the drain of MOS tube Q3 and the source of MOS tube Q4, a resistor R5 is connected in series between any point A and any point B, the gates of MOS tube Q1 and MOS tube Q4 are respectively connected to the first drive, the gates of MOS tube Q2 and MOS tube Q3 are respectively connected to the second drive, and the sources of MOS tube Q1 and MOS tube Q3 are respectively connected to the positive terminal of the battery. The utility model has a simple circuit, can limit the battery to generate a large impact current when charging, and limit the battery to generate an oscillating high voltage when the large current is disconnected, and has a MOS tube fault self-diagnosis function.

Description

Technical Field

[0001] The utility model relates to a grid staggered driving MOS tube redundant double pre-charging circuit. Background Art

[0002] In the rapidly developing rail transit vehicles, whether it is subways, high-speed railways, or motor vehicles, the legal standards for switch components that control the high-voltage and high-current charging of on-board backup batteries are stringent, and the reliability requirements are high. Commonly used devices are DC contactors, relays, IGBTs, MOS tubes, etc. However, DC contactors have disadvantages such as large size and high power consumption; relays are currently less used in rail transit and there are risks such as easy leakage of arc-extinguishing inert gas and easy adhesion of contacts; IGBTs have disadvantages such as large size, high on-resistance, and complex driving. MOS tubes are widely used in controlling battery charging and discharging and are simple to drive, but when used in high-current and high-voltage charging control circuits, due to the rated current and rated voltage limitations of a single MOS tube, multiple MOS tubes need to be used in series and parallel. When used in parallel, since the parameters of each MOS tube cannot be consistent, there is a time difference in gate driving. The MOS tube that is turned on first (or turned off later) must first withstand several times the current impact, which can easily damage the MOS tube. Due to the production process of MOS tubes, their withstand voltage is proportional to the on-resistance. If a MOS tube with a high withstand voltage is selected, the on-resistance of the MOS tube will increase. When it is used in higher voltage scenarios, multiple MOS tubes are used in series to reduce the on-resistance and loss. However, when cutting off a large current, the insulation performance of the MOS tube will be damaged at the moment of disconnection, making it difficult to select the MOS tube. Therefore, how to arrange the MOS tube in the circuit so that it can limit the large impact current generated by the battery during charging without damaging the MOS tube itself has become a current research topic. Utility Model Content

[0003] The utility model aims to provide a redundant dual pre-charging circuit of a MOS tube with a simple circuit, which can limit the battery to generate a large impact current when charging and can limit the battery to generate an oscillating high voltage when the large current is disconnected.

[0004] The utility model is realized by the following scheme:

[0005] A gate staggered drive MOS tube redundant dual pre-charging circuit comprises a MOS tube Q1, a MOS tube Q2, a MOS tube Q3 and a MOS tube Q4, wherein the drain of the MOS tube Q1 is connected to the source of the MOS tube Q2, an arbitrary point A is taken between the drain of the MOS tube Q1 and the source of the MOS tube Q2, the drain of the MOS tube Q3 is connected to the source of the MOS tube Q4, an arbitrary point B is taken between the drain of the MOS tube Q3 and the source of the MOS tube Q4, a resistor R5 is connected in series between the arbitrary point A and the arbitrary point B, the gates of the MOS tube Q1 and the MOS tube Q4 are respectively connected to a first drive, the gates of the MOS tube Q2 and the MOS tube Q3 are respectively connected to a second drive, the sources of the MOS tube Q1 and the MOS tube Q3 are respectively connected to a positive terminal of a battery, the drains of the MOS tube Q2 and the MOS tube Q4 are respectively connected to a positive terminal of a charger, and the negative terminal of the battery is connected to a negative terminal of the charger. The battery in the utility model includes a battery pack, a battery package, a single battery, etc. When selecting the four MOS tubes, MOS tube Q1, MOS tube Q2, MOS tube Q3, and MOS tube Q4, the corresponding models are generally selected according to needs, and the parameter margins selected for each MOS tube are ensured to be sufficient, so as to ensure that during the circuit charging process, even if a MOS tube fails, the circuit can maintain normal charging and operation, making the entire circuit system more reliable.

[0006] The setting of R5 can play the role of pre-charging current limiting, and can also check the current value on R5 when MOS tube Q1, MOS tube Q2, MOS tube Q3, and MOS tube Q4 are all turned on for charging or during discharging to predict whether the four MOS tubes are damaged.

[0007] Furthermore, it also includes a voltage stabilizing diode ZD1, a voltage stabilizing diode ZD2, a voltage stabilizing diode ZD3 and a voltage stabilizing diode ZD4, wherein the anode and cathode of the voltage stabilizing diode ZD1, the voltage stabilizing diode ZD2, the voltage stabilizing diode ZD3 and the voltage stabilizing diode ZD2 are connected to the source and gate of the MOS tube Q1, the MOS tube Q2, the MOS tube Q3 and the MOS tube Q4 in a one-to-one correspondence, and the voltage stabilizing diode ZD1, the voltage stabilizing diode ZD2, the voltage stabilizing diode ZD3 and the voltage stabilizing diode ZD4 are connected to resistors R1, R2, R3 and R4 in a one-to-one correspondence. A voltage stabilizing diode and a resistor are arranged on each MOS tube, which can protect the normal operation of each MOS tube, ensure that the MOS tube works in a safe area, and reasonably adjust the shutdown and startup time, etc.

[0008] Furthermore, the gates of the MOS transistors Q1 and Q4 are connected to the circuit connected to the first drive with a resistor R6, and the gates of the MOS transistors Q2 and Q3 are connected to the circuit connected to the second drive with a resistor R7. The setting of the resistors R6 and R7 can match the level signals of the first drive and the second drive, and the parameters of the resistors R6 and R7 can be adjusted to make the circuit more suitable for the signal sources of the first drive and the second drive given by the battery management system.

[0009] The utility model discloses a redundant dual pre-charging circuit of MOS tubes driven by staggered gates. The circuit is simple. The gates of MOS tubes are driven by staggered gates. When high-current charging is turned on, a large impact current generated by the battery can be limited. When the high current is disconnected, an oscillating high voltage generated by the battery can be limited. The MOS tubes are more resistant to voltage and current impacts. The redundant design of the MOS tubes has a self-diagnosis function for MOS tube faults, and the circuit is more reliable. The redundant dual pre-charging circuit of MOS tubes driven by staggered gates of the utility model has low requirements on parameter consistency when the MOS tubes are used in parallel, a wide selection range, and a simple driving design. It is more in line with the application scenarios of battery pre-charging and high-current charging, protects the MOS tubes themselves, and can extend the service life of the battery, making the battery safer and more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a circuit diagram of a redundant dual pre-charging circuit for MOS tubes with staggered gate driving in Example 1. DETAILED DESCRIPTION

[0011] The embodiments are only intended to illustrate one implementation of the present invention and are not intended to limit the protection scope of the present invention.

[0012] Example 1

[0013] A gate staggered driving MOS tube redundant dual pre-charging circuit comprises a MOS tube Q1, a MOS tube Q2, a MOS tube Q3, a MOS tube Q4, a voltage regulator diode ZD1, a voltage regulator diode ZD2, a voltage regulator diode ZD3 and a voltage regulator diode ZD4, the drain of the MOS tube Q1 is connected to the source of the MOS tube Q2, an arbitrary point A is taken between the drain of the MOS tube Q1 and the source of the MOS tube Q2, the drain of the MOS tube Q3 is connected to the source of the MOS tube Q4, an arbitrary point B is taken between the drain of the MOS tube Q3 and the source of the MOS tube Q4, a resistor R5 is connected in series between the arbitrary point A and the arbitrary point B, the gates of the MOS tube Q1 and the MOS tube Q4 are respectively connected to a first driver 1 and a resistor R6 is connected in series on the connection circuit, the MOS tubes Q2, M The gates of the MOS tube Q3 are respectively connected to the second driver 2 and a resistor R7 is commonly connected in series on the connection circuit. The anodes and cathodes of the zener diodes ZD1, ZD2, ZD3 and ZD4 are connected to the sources and gates of the MOS tubes Q1, Q2, Q3 and Q4 in a one-to-one correspondence. The zener diodes ZD1, ZD2, ZD3 and ZD4 are connected to the resistors R1, R2, R3 and R4 in a one-to-one correspondence. The sources of the MOS tubes Q1 and Q3 are respectively connected to the positive terminals of the batteries. The drains of the MOS tubes Q2 and Q4 are respectively connected to the positive terminals of the chargers. The negative terminals of the batteries are connected to the negative terminals of the chargers.

[0014] In this embodiment 1, two pre-filling loops are formed, and the pre-filling loop 1 is:

[0015] Charger+→Q4→B→R5→A→Q1→Battery+→Battery-→Charger-

[0016] Pre-charge circuit 2 is:

[0017] Charger+→Q2→A→R5→B→Q3→Battery+→Battery-→Charger-

[0018] Pre-charging loop 1 is controlled by a first driver, and pre-charging loop 2 is controlled by a second driver. The first driver and the second driver are generally arranged in a battery management system, and four MOS tubes form a gate staggered drive.

[0019] When the battery needs full current charging, first close one of the pre-charging circuits to pre-charge the battery. When the battery voltage reaches the voltage value that can be charged evenly, close the other pre-charging circuit. When the two pre-charging circuits are turned on successively, resistor R5 is short-circuited, and the battery exits the pre-charging mode and enters the full current charging stage. At the end of charging, disconnect one of the pre-charging circuits first, and then disconnect the other pre-charging circuit. When the two pre-charging circuits are disconnected successively, the charging is terminated. Before both pre-charging circuits are closed and the battery starts full current charging, and both pre-charging circuits are disconnected and the battery stops charging, only one pre-charging circuit is kept turned on, so as to ensure that the battery starts full current charging and ends full current charging to achieve the purpose of current reduction, avoiding the risk of excessive impact current breaking down the MOS tube when the battery starts full current charging, and the risk of overvoltage damaging the MOS tube when the battery ends full current charging.

[0020] In high-reliability charging applications, the circuit of this embodiment 1 can also play the role of MOS tube redundancy and self-diagnosis of MOS tube failure: when charging normally, the resistor R5 is short-circuited, and the MOS tubes Q1, Q2, Q3, and Q4 form a bridge. When the MOS tubes Q1, Q2, Q3, and Q4 are all normal, the bridge is balanced, and the current flowing through the two ends of AB is 0 A. If one of the MOS tubes fails, the bridge is unbalanced, and there is a voltage across the resistor R5, that is, a current flows through the resistor R5. According to this characteristic, by monitoring the current flowing through the two ends of the resistor R5 or the voltage generated by the current at the two ends of the resistor R5, it is determined whether there is a MOS tube failure.

Claims

1. A gate staggered drive MOS tube redundant double pre-charging circuit, characterized in that: The invention comprises a MOS transistor Q1, a MOS transistor Q2, a MOS transistor Q3 and a MOS transistor Q4, wherein the drain of the MOS transistor Q1 is connected to the source of the MOS transistor Q2, an arbitrary point A is taken between the drain of the MOS transistor Q1 and the source of the MOS transistor Q2, the drain of the MOS transistor Q3 is connected to the source of the MOS transistor Q4, an arbitrary point B is taken between the drain of the MOS transistor Q3 and the source of the MOS transistor Q4, a resistor R5 is connected in series between the arbitrary point A and the arbitrary point B, the gates of the MOS transistor Q1 and the MOS transistor Q4 are respectively connected to a first driver, the gates of the MOS transistor Q2 and the MOS transistor Q3 are respectively connected to a second driver, the sources of the MOS transistor Q1 and the MOS transistor Q3 are respectively connected to a positive terminal of a battery, the drains of the MOS transistor Q2 and the MOS transistor Q4 are respectively connected to a positive terminal of a charger, and the negative terminal of the battery is connected to a negative terminal of the charger.

2. A gate staggered drive MOS tube redundant double pre-charging circuit as claimed in claim 1, characterized in that: It also includes a Zener diode ZD1, a Zener diode ZD2, a Zener diode ZD3 and a Zener diode ZD4, wherein the anodes and cathodes of the Zener diodes ZD1, ZD2, ZD3 and ZD2 are connected to the sources and gates of the MOS transistors Q1, Q2, Q3 and Q4 in a one-to-one correspondence, and the Zener diodes ZD1, ZD2, ZD3 and ZD4 are connected to resistors R1, R2, R3 and R4 in a one-to-one correspondence.

3. A gate staggered driving MOS tube redundant dual pre-charging circuit as described in claim 1 or 2, characterized in that: The gates of the MOS transistors Q1 and Q4 are connected to the circuit connected to the first driver with a resistor R6 in series, and the gates of the MOS transistors Q2 and Q3 are connected to the circuit connected to the second driver with a resistor R7 in series.

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