A control circuit and control method for reducing power-on pulse current

Abstract

This invention discloses a control circuit and method for reducing power-on pulse current, including an MCU motor driver, a DC-DC power supply circuit, a pulse width control circuit, and a motor drive control power supply circuit. The pulse width control circuit energizes the capacitors in the main circuit of the controller, and the motor drive control power supply circuit provides power to the motor control power section during motor operation. The motor drive control power supply circuit is equipped with normally open relay contacts and a bus capacitor. The pulse width control circuit is used to energize the capacitors in the main circuit of the controller. The motor drive control power supply circuit provides power to the power section during motor operation. When the driver is powered on, the pulse width control circuit controls the pulse width control circuit to charge the bus capacitor with a certain pulse width. When the voltage of the capacitor in the motor drive control power supply circuit reaches more than 90% of the power supply voltage, the RLY relay control switch is closed, and the motor drive control power supply circuit is connected to the power supply.

Description

Technical Field

[0001] This invention relates to a controller, and more particularly to a control circuit and control method for reducing power-on pulse current in controller products such as electric motorcycles, large lawnmowers, ATVs, and electric forklifts. Background Technology

[0002] For high-powered battery-powered devices such as electric mobility scooters and electric forklifts, safety considerations necessitate the ability to disconnect the battery from the drive motor. This allows for timely and effective protection activation in case of abnormalities in the motor or drive power, preventing the fault from spreading. A common practice is to install a high-current contactor or a large-diameter fuse between the battery and the controller. However, this results in a large current pulse when power is applied. To prevent damage to the contactor or fuse from this large current pulse, even larger-diameter fuses or contactors are typically used, which undoubtedly delays the protection function and increases system costs. Summary of the Invention

[0003] This invention addresses the shortcomings of existing controllers for electric motorcycles, large lawnmowers, ATVs, and electric forklifts, which suffer from high power-on pulse current, leading to damage to contactors or fuses, delayed protection functions, and high protection system costs. It provides a control circuit and method that effectively reduces the current surge pulse phenomenon during driver power-on, resulting in faster protection response and lower protection control costs.

[0004] The specific technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: a control system for reducing power-on pulse current, comprising an MCU controller and a DC-DC power supply circuit, characterized in that: it further comprises a pulse width control circuit and a motor drive control power supply circuit. The pulse width control circuit is used to power the bus capacitor on the main circuit inside the controller, and the motor drive control power supply circuit is used to provide power to the motor control power part when the motor is running. The motor drive control power supply circuit is provided with a normally open contact of a relay and a bus capacitor. One end of the normally open contact of the relay is electrically connected to the emitter of a first transistor. The collector of the first transistor is connected in series with a first diode. The anode of the first diode is electrically connected to the collector of the first transistor. The cathode of the first diode is connected in series with a first resistor and then electrically connected to the other end of the normally open contact of the relay. At the same time, the other end of the normally open contact of the relay is connected in parallel to the positive terminal of the bus capacitor and the MCU controller. The base of the first transistor is electrically connected to the emitter of a second transistor, and the base of the second transistor is electrically connected to the MCU controller. The DC-DC power supply circuit provides DC-DC power to the MCU controller, the pulse width control circuit, and the motor drive control power supply circuit. The design incorporates two parallel circuits: a pulse width control circuit and a motor drive control power supply circuit. When the driver is powered on, the pulse width control circuit charges the bus capacitor with a specific pulse width. When the voltage of the capacitor in the motor drive control power supply circuit reaches a certain ratio of the set power supply voltage, the normally open contact switch of the relay is closed, and the motor drive control power supply circuit is connected to the power supply. This effectively reduces the current surge pulse phenomenon when the driver is powered on, reduces the power-on pulse current, provides fast protection response, and has low protection control costs.

[0005] Preferably, the relay control circuit used in the normally open contact of the relay includes a relay coil control circuit and circuits at both ends of the normally open contact. The relay coil control circuit uses a configuration where one end of the coil is connected in series with the anode of a second diode, the cathode of the second diode is electrically connected to the collector of a third transistor, the base of the third transistor is connected in series with a second resistor and then electrically connected to the relay signal drive terminal, and the base of the third transistor is connected in series with a fifth resistor and then electrically connected to the emitter of the third transistor and grounded. The anode of the second diode is connected in series with a fourth resistor and a third resistor and then electrically connected to grounded. The series connection point of the fourth and third resistors is electrically connected to the relay coil signal detection terminal. Simultaneously, the series connection point of the fourth and third resistors is electrically connected to the anode of the third diode and then connected to a +3.3V power supply. A fifth capacitor is connected in parallel across the third resistor, and a fourth diode is connected in parallel across the relay coil. The anode of the fourth diode is electrically connected to the relay coil power supply. This improves the simplicity, reliability, and effectiveness of the triggering control of the normally open contact of the relay.

[0006] Preferably, the normally open contact of the relay in the relay control circuit uses the following circuit configuration: one end of the normally open contact is electrically connected to the power supply voltage terminal; the power supply voltage terminal is connected in series with the anode of the fifth diode and then electrically connected to the emitter of the first transistor; the collector of the first transistor is connected in series with the first diode and the first resistor and then electrically connected to the other end of the normally open contact; the anode of the first diode is connected to the collector of the first transistor; the base of the first transistor is connected in series with the seventh resistor and then electrically connected to the collector of the second transistor; the base of the second transistor is connected in series with the eighth resistor and then electrically connected to the capacitor charging signal; and multiple electrolytic capacitors are connected in parallel between the other end of the normally open contact and the circuit power ground. This improves the simplicity, reliability, stability, and effectiveness of the normally open contact control.

[0007] Another objective of this invention application is to provide a control method for reducing power-on pulse current control circuits, characterized by comprising the following control method.

[0008] A1. The control system for reducing power-on pulse current in the above technical solution controls the pulse width control circuit to charge the bus capacitor with a certain pulse width when the MCU motor driver is powered on. When the voltage of the bus capacitor in the motor drive control power supply circuit reaches more than 90% of the power supply voltage, the normally open contact of the relay closes and the motor drive control power supply circuit is connected to the power supply.

[0009] A2. When the MCU motor driver is powered on, the normally open contact of the relay RLY is in the open state, the first transistor is also in the open state, and there is no charge on the bus capacitor C.

[0010] A3. The DC-DC power supply circuit supplies power to the MCU controller, and the MCU motor driver starts to work, detecting the voltage on the bus capacitor C;

[0011] A4. If no voltage is detected in step A3 above, the MCU motor driver PWM signal controls the first and second transistors to turn on. The small current controlled by the PWM pulse width charges the bus capacitor through the first transistor, the first diode, and the first resistor. The first diode ensures unidirectional current flow, and the first resistor limits the amount of current flowing into the bus.

[0012] A5. When the MCU controller detects that the bus capacitor voltage reaches 90% of the supply voltage, the MCU motor driver controls the relay to close the normally open contacts of the relay. Since the voltage difference across the relay contacts is very small, a large current pulse will not be generated in the motor drive control power supply circuit.

[0013] A6. After the normally open contact of the relay is closed, the energy in the bus capacitor and the motor drive control power supply circuit is provided through the contact path after the relay is closed;

[0014] A7. After the normally open contact of the relay is closed, the MCU motor driver controls the second and first transistors to open, cutting off the current flow in step A4 above. Only the current flow in step A6 above can be maintained, ensuring that the charge on the bus capacitor is slowly charged at a certain slope, without causing an impact on the power supply. By reducing the voltage difference, the impact on the power supply voltage when the MCU motor driver is powered on is weakened.

[0015] Effectively controlling and reducing the power-on pulse current effectively solves the problem of large voltage difference in the motor driver when it is powered on. By reducing the voltage difference, the impact on the power supply voltage during power-on is weakened, effectively protecting the motor driver from damage caused by current surges.

[0016] The beneficial effects of this invention are: This patent proposes a scheme to reduce power-on current pulses, which can effectively reduce the current pulse phenomenon during power-on. This patent designs two parallel circuits: a pulse width control circuit and a motor drive control power supply circuit. The pulse width control circuit is used to power the capacitors on the main circuit inside the controller. The motor drive control power supply circuit is used to supply power to the power section when the motor is running. When the driver is powered on, the pulse width control circuit controls the pulse width control circuit to charge the bus capacitor at a certain pulse width. When the voltage of the capacitor in the motor drive control power supply circuit reaches more than 90% of the power supply voltage, the RLY relay control switch is closed, and the motor drive control power supply circuit is connected to the power supply. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the control system structure of a power-on pulse current reduction method according to the present invention.

[0018] Figure 2 This is a schematic diagram of the relay circuit in a method for reducing power-on pulse current according to the present invention. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0020] Example 1

[0021] Figure 1 , Figure 2 In the illustrated embodiment, a control system for reducing power-on pulse current includes an MCU controller and a DC-DC power supply loop, and further includes a pulse width control circuit (see...). Figure 1 Arrow A indicates the direction of the circuit) and a motor drive control power supply circuit (see... Figure 1(The circuit shown by arrow B) The pulse width control circuit powers the bus capacitor C in the main circuit of the controller. The motor drive control power supply circuit provides power to the motor control power section when the motor is running. The motor drive control power supply circuit is equipped with a normally open relay contact and a bus capacitor. One end of the normally open relay contact is electrically connected to the emitter of the first transistor Q1. The collector of the first transistor Q1 is connected in series with the first diode D1. The anode of the first diode is electrically connected to the collector of the first transistor Q1. The cathode of the first diode D1 is connected in series with the first resistor R1 and then electrically connected to the other end of the normally open contact of the relay RLY. At the same time, the other end of the normally open contact of the relay RLY is connected in parallel to the positive terminal of the bus capacitor C and the MCU controller. The base of the first transistor Q1 is electrically connected to the emitter of the second transistor Q2. The base of the second transistor is electrically connected to the MCU controller. The DC-DC power supply circuit provides DC-DC power to the MCU controller, the pulse width control circuit, and the motor drive control power supply circuit.

[0022] The relay control circuit used for the normally open contact includes a relay coil control circuit and circuits at both ends of the normally open contact. The relay coil control circuit uses a configuration where one end of the coil (3) is connected in series with the anode of the second diode (D2). The cathode of the second diode (D2) is electrically connected to the collector of the third transistor (Q3). The base of the third transistor (Q3) is connected in series with a second resistor and then electrically connected to the relay signal drive terminal RLY-DRV (RLY is the abbreviation for relay, DRV is the abbreviation for drive). The base of the third transistor (Q3) is connected in series with a fifth resistor (R5) and then electrically connected to the emitter of the third transistor (Q3) and connected to the circuit power ground (GND). The second diode... The anode of diode D2 is connected in series with resistors R4 and R3, and then connected to the circuit power supply ground. The series connection of resistors R4 and R3 is connected to the relay coil signal detection terminal RLY-DECT (RLY is the abbreviation for relay, and DECT means detection, used to detect the relay coil). At the same time, the series connection of resistors R4 and R3 is connected to the anode of diode D3 and then connected to a +3.3V power supply. A capacitor C5 is connected in parallel across resistor R3. Diode D4 is connected in parallel across the relay coil, and the anode of diode D4 is connected to the 14.3V power supply of the relay coil.

[0023] The normally open contact of the relay is used in the relay control circuit, and the circuit at both ends of the normally open contact of the relay is used as one end of the normally open contact (see...). Figure 2 In RLY, terminals 7, 8, and 9 are electrically connected to the power supply voltage terminal B+. The power supply voltage terminal B+ is connected in series with the anode of diode D5 (number 5) and then electrically connected to the emitter of transistor Q1. The collector of transistor Q1 is connected in series with diode D1 and resistor R1 and then electrically connected to the other end of the normally open contact of the relay (see...). Figure 2In the RLY circuit, terminals 4, 5, and 6 are electrically connected. The anode of diode D1 is electrically connected to the collector of transistor Q1. The base of transistor Q1, connected in series with resistor R7 (7), is electrically connected to the collector of transistor Q2. The base of transistor Q2, connected in series with resistor R8 (8), is electrically connected to the capacitor charging signal PWM. Multiple electrolytic capacitors are connected in parallel between the other end of the relay's normally open contact and the circuit power ground. These parallel electrolytic capacitors consist of capacitors C1, C2, C3, and C4, each with a capacitance of 330µF / 100V. Figure 2 Multiple electrolytic capacitors are connected in parallel in the circuit to increase the capacitance value. The larger the capacitance, the better the filtering effect provided during motor operation; correspondingly, in... Figure 1 In the simplified circuit diagram, a bus capacitor C is used to represent the circuit structure.

[0024] Example 2:

[0025] Figure 1 , Figure 2 In the illustrated embodiment, a control method for reducing the power-on pulse current control circuit includes the following control method:

[0026] A1. When the MCU motor driver is powered on, the pulse width control circuit is controlled to charge the bus capacitor with a certain pulse width. When the voltage of the bus capacitor in the motor drive control power supply circuit reaches more than 90% of the power supply voltage B1+, the normally open contact of the relay closes and the motor drive control power supply circuit is connected to the power supply.

[0027] A2. When the MCU motor driver is powered on, the normally open contact of the relay RLY is in the open state, the first transistor is also in the open state, and there is no charge on the bus capacitor C.

[0028] A3. The DC-DC power supply circuit supplies power to the MCU controller. The MCU controller starts working, detects the voltage on the bus capacitor C, and samples the voltage of this capacitor.

[0029] A4. If no voltage is detected in step A3 above, the MCU motor driver PWM signal controls the first and second transistors to turn on. The small current controlled by the PWM pulse width charges the bus capacitor through the first transistor, the first diode, and the first resistor. The first diode ensures unidirectional current flow, and the first resistor limits the amount of current flowing into the bus.

[0030] A5. When the MCU motor driver detects that the bus capacitor voltage has reached 90% of the supply voltage, the MCU controller controls the relay to close the normally open contacts of the relay. Since the voltage difference across the relay contacts is very small, a large current pulse will not be generated in the motor drive control power supply circuit.

[0031] A6. After the normally open contact of the relay is closed, the energy in the bus capacitor and the motor drive control power supply circuit is provided through the contact path after the relay is closed;

[0032] A7. After the normally open contact of the relay is closed, the MCU motor driver controls the second and first transistors to open, cutting off the current flow in step A4 above. Only the current flow in step A6 above can be maintained, ensuring that the charge on the bus capacitor is slowly charged at a certain slope, without causing an impact on the power supply. By reducing the voltage difference, the impact on the power supply voltage when the MCU motor driver is powered on is weakened.

[0033] During operation, when the motor driver is powered on, the normally open contact switch RLY of the relay is in the open state, and transistor Q1 is also in the open state. There is no charge on the bus capacitor C in the motor drive control power supply circuit. The MCU motor driver is powered through the DC-DC power supply circuit. The MCU motor driver starts working and detects the voltage on the main circuit bus capacitor C. If no voltage is detected, the MCU motor driver controls transistors Q1 and Q2 to turn on via a PWM signal. Current flows through the pulse width control circuit to charge the bus capacitor. Diode D1 ensures unidirectional current flow, and resistor R1 and the PWM signal limit the current flowing into the bus capacitor C. When the MCU motor driver detects that the voltage on the bus capacitor C reaches 90% of the power supply voltage, the MCU controls the RLY relay, causing the normally open contact of the relay to close. Because the voltage difference across the relay is very small, a large current pulse will not be formed on the bus. After closing, the energy for the bus capacitor C and the motor drive control power supply circuit is supplied through the motor drive control power supply circuit. After the RLY relay contacts are closed, the MCU controls Q2 and Q1 to open, cutting off the pulse width control circuit and only keeping the motor drive control power supply circuit open. In this way, the charge on the bus capacitor can be slowly charged at a certain slope, without impacting the power supply section, thus protecting the motor driver and other components from damage caused by current surges.

[0034] The above content and structure describe the basic principles, main features, and advantages of the product of this invention, which should be understood by those skilled in the art. The examples and descriptions above are merely illustrative of the principles of this invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A control system for reducing power-on pulse current, comprising an MCU motor driver and a DC-DC power supply circuit, characterized in that, It also includes a pulse width control circuit and a motor drive control power supply circuit. The pulse width control circuit powers the bus capacitor on the main circuit inside the controller, and the motor drive control power supply circuit provides power to the motor control power section when the motor is running. The motor drive control power supply circuit has a normally open relay contact and a bus capacitor. One end of the normally open relay contact is connected in series with a fifth diode and then electrically connected to the emitter of a first transistor. The collector of the first transistor is connected in series with the first diode. The anode of the first diode is electrically connected to the collector of the first transistor. The cathode of the first diode is connected in series with a first resistor and then electrically connected to the other end of the normally open relay contact. At the same time, the other end of the normally open relay contact is connected in parallel to the positive terminal of the bus capacitor and the MCU controller. The base of the first transistor is connected to the emitter of a second transistor, and the base of the second transistor is connected to the MCU controller. The DC-DC power supply circuit provides power to the MCU controller, the pulse width control circuit, and the motor drive control power supply circuit. DC-DC power supply; the relay control circuit used for the normally open contact of the relay includes a relay coil control circuit and circuits at both ends of the normally open contact of the relay. The relay coil control circuit is configured such that one end of the coil is connected in series with the anode of the second diode, the cathode of the second diode is electrically connected to the collector of the third transistor, the base of the third transistor is connected in series with the second resistor and then electrically connected to the relay signal drive terminal, the base of the third transistor is connected in series with the fifth resistor and then electrically connected to the emitter of the third transistor and electrically connected to the circuit power supply ground; the anode of the second diode is connected in series with the fourth resistor and the third resistor and then electrically connected to the circuit power supply ground; the series connection of the fourth resistor and the third resistor is electrically connected to the relay coil signal detection terminal; the series connection of the fourth resistor and the third resistor is electrically connected to the anode of the third diode and then connected to the +3.3V power supply; the fifth capacitor is connected in parallel across the third resistor; the fourth diode is connected in parallel across the relay coil, and the anode of the fourth diode is electrically connected to the relay coil power supply.

2. The control system for reducing power-on pulse current according to claim 1, characterized in that, The normally open contact of the relay used in the relay control circuit adopts the following circuit configuration: one end of the normally open contact is electrically connected to the power supply voltage terminal; the power supply voltage terminal is connected in series with the anode of the 5th diode and then electrically connected to the emitter of the 1st transistor; the collector of the 1st transistor is connected in series with the 1st diode and the 1st resistor and then electrically connected to the other end of the normally open contact; the anode of the 1st diode is electrically connected to the collector of the 1st transistor; the base of the 1st transistor is connected in series with the 7th resistor and then electrically connected to the collector of the 2nd transistor; the base of the 2nd transistor is connected in series with the 8th resistor and then electrically connected to the capacitor charging signal; and multiple electrolytic capacitors are connected in parallel between the other end of the normally open contact and the circuit power ground.

3. A control method for reducing the power-on pulse current control circuit, characterized in that, Including the following control methods: A1. The control system for reducing power-on pulse current as described in any one of claims 1 to 2, when the MCU motor driver is powered on, controls the pulse width control circuit to charge the bus capacitor with a certain pulse width. When the voltage of the bus capacitor in the motor drive control power supply circuit reaches more than 90% of the power supply voltage, the normally open contact of the relay closes, and the motor drive control power supply circuit is connected to the power supply. A2. When the MCU motor driver is powered on, the normally open contact of the relay RLY is in the open state, the first transistor is also in the open state, and there is no charge on the bus capacitor C. A3. The DC-DC power supply circuit supplies power to the MCU motor driver. The MCU motor driver starts working and detects the voltage on the bus capacitor C. A4. If no voltage is detected in step A3 above, the MCU motor driver PWM signal controls the first and second transistors to turn on. The small current controlled by the PWM pulse width charges the bus capacitor through the first transistor, the first diode, and the first resistor. The first diode ensures unidirectional current flow, and the first resistor limits the amount of current flowing into the bus. A5. When the MCU motor driver detects that the bus capacitor voltage reaches 90% of the supply voltage, the MCU controller controls the relay to close the normally open contacts of the relay. Since the voltage difference across the relay contacts is very small, a large current pulse will not be generated in the motor drive control power supply circuit. A6. After the normally open contact of the relay is closed, the energy in the bus capacitor and the motor drive control power supply circuit is provided through the contact path after the relay is closed; A7. After the normally open contact of the relay is closed, the MCU controller controls the second and first transistors to open, cutting off the current flow in step A4 above. Only the current flow in step A6 above can be maintained, ensuring that the charge on the bus capacitor is slowly charged at a certain slope, without causing an impact on the power supply. By reducing the voltage difference, the impact on the power supply voltage when the MCU motor driver is powered on is weakened.

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