Low-speed electric vehicle slow slope sliding control method and control system thereof

Abstract

The invention discloses a slow slope sliding control method and system for a low-speed electric vehicle, and the method comprises the steps: carrying out the detection and processing of output signals of different MCU (Microprogrammed Control Unit) output 1 of a plurality of different control modes: a normal state working control mode, a cart control mode, a battery online slope sliding control mode and a battery disconnection slope sliding control mode; the brake current is generated for the BLDC motor through connection and conversion of the relay contacts, the motor is braked, and therefore the vehicle is prevented from sliding on a slope. When the control system is shut down due to power failure or other abnormal shutdown conditions, the vehicle can be effectively prevented from sliding slowly, and the potential safety risk of rapid sliding of the low-speed electric vehicle is avoided.

Description

Technical Field

[0001] The present invention relates to a low-speed electric vehicle control method, and in particular to a low-speed electric vehicle gentle slope control method and a control system thereof, which are used for controlling the low-speed electric vehicle to prevent it from sliding down a slope. Background Art

[0002] Low-speed electric vehicles (such as electric wheelchairs, electric scooters, golf carts, golf carts, and electric tricycles) are used as transportation or auxiliary tools to meet the needs of people with mobility issues for longer distances, or to meet the needs of people with mobility issues, thereby improving travel efficiency. However, to reduce manufacturing costs, existing low-speed electric vehicles use a combination of manual and electronic parking controls. This parking control mode poses a safety risk of the vehicle rapidly rolling down a slope if the operator fails to engage the manual parking lever in a timely manner due to a power outage or other abnormality in the control system. Summary of the Invention

[0003] The present invention aims to solve the current situation in which, when the control system is shut down due to power outage or other abnormalities, if the operator fails to pull up the manual parking brake in time, the vehicle may easily face the safety risk of rapidly rolling down a slope. The present invention provides a low-speed electric vehicle slow rolling control method and control system that can effectively suppress the vehicle from slowly rolling down a slope when the control system is shut down due to power outage or other abnormalities, thereby avoiding the safety risk of rapidly rolling down a slope for the low-speed electric vehicle.

[0004] To achieve the above objectives, the present invention adopts a method for controlling a low-speed electric vehicle to roll down a slope, including the following state roll down control modes: A1. Normal operating control mode: The MCU output 1 signal pulls the MOSFET gate low, turning off the MOSFET. The battery charges the bus capacitor, which is located on the bus. The relay drive circuit closes the relay contacts, connecting the battery to the bus through the relay. The low-speed electric vehicle is in normal operating condition. A2. Abnormal detection working control mode: The output signal of MCU output 1 is in the disabled state. If the MCU detects that the MCU input 1 signal detects that the cart switch is in the open state, it is determined that the MCU control system is in an abnormal state, and an alarm indication is issued through the alarm-related modules; A3. Cart control mode: After the MCU control system is shut down, if the external cart switch is turned to the off state, the MOSFET tube loses drive and is cut off, and the vehicle can be pushed normally; A4. In slope control mode with the battery online: After the MCU control system is shut down, the battery voltage drives the MOSFET to conduct, connecting the relay's C contact and NC contact. The BLDC motor's back EMF, passing through the rectifier and filter circuit, outputs a DC voltage to the relay's C contact and NC contact, which then conducts to the MOSFET, forming a current loop. The BLDC motor generates braking current, braking the motor and preventing the vehicle from rolling down the slope. If the current flowing through the MOSFET is too high, it enters its linear region, limiting the current and thus limiting the motor's braking torque. A5. Hill-rolling control mode when the battery is disconnected: After the MCU control system is shut down, the BLDC motor's back EMF is rectified and filtered to output a DC voltage, driving the MOSFET to conduct, forming a current loop. The BLDC motor generates a braking current, braking the motor and preventing the vehicle from rolling down the hill. When the current is too high, the MOSFET enters the linear region to limit the current, thereby limiting the motor's braking torque.

[0005] It can effectively suppress the vehicle from slowly sliding down the slope when the control system is shut down due to power outage or other abnormalities, and avoid the hidden safety risks of low-speed electric vehicles sliding down the slope quickly. It can effectively suppress the vehicle from slowly sliding down the slope when the control system is shut down due to power outage or other abnormalities, and avoid the hidden safety risks of low-speed electric vehicles sliding down the slope quickly.

[0006] Preferably, the above step A1 includes the following execution steps: Step 1: MCU outputs 1 output signal, which is processed by output processing 1 to pull down the gate of MOSFET tube, and MOSFET tube is turned off; Step 2: The MCU pre-charge control output signal controls the pre-charge circuit to work, and the battery charges the bus capacitor CAP1. Step 3: After the voltage across CAP1 rises to a stable level, the MCU relay drive output signal drives the relay NO contact and C contact to close through the relay drive circuit, and the battery is connected to the busbar through the relay.

[0007] Improve the reliability, stability and effectiveness of the MCU relay drive output signal in driving the relay NO contact and C contact to close.

[0008] Preferably, in the above step A1, MCU output 1 is output disabled. If the cart switch is in the off-circuit state, the MCU detects the MCU input 1 signal and detects that the cart switch is in the off-circuit state, indicating that the system is abnormal, that is, an alarm indication is issued through the alarm-related module, thereby improving the effectiveness of the system abnormality alarm prompt.

[0009] Preferably, in step A4 above, after the MCU control system is shut down, the battery voltage is reduced by voltage processing 1, and then the MOSFET tube is turned on through the closed cart switch and voltage processing 3; the C contact of the relay is connected to the NC contact; the back electromotive force of the BLDC motor is output as a DC voltage through three-phase half-bridge rectification and CAP1 filtering. The voltage passes through the C contact of the relay, the NC contact of the RELAY, the MOSFET tube, and the current is collected to GND to form a current loop. The BLDC motor generates a braking current to brake the motor, thereby suppressing the vehicle from rolling down the slope. When the current is too large, the constant current module causes the MOSFET tube to enter the linear region to operate to limit the current passing through, thereby limiting the braking torque of the motor. After the MOSFET tube is turned on, the gate power consumption is low, thereby achieving a low-power design for the system. Improving the simplicity, reliability and effectiveness of vehicle rolling down the slope control mode when the battery is online.

[0010] Preferably, in the above-mentioned step A5, after the MCU control system is shut down, the back electromotive force of the BLDC motor outputs a DC voltage through the three-phase half-bridge rectification and CAP1 capacitor filtering, and the voltage drives the MOSFET tube to turn on through voltage processing 2, the closed cart switch, and voltage processing 3; the voltage passes through the RELAY contact C, the RELAY contact NC, the MOSFET tube, and the current is collected to the power ground GND to form a current loop, and the BLDC motor generates a braking current to brake the motor, thereby suppressing the vehicle from sliding downhill. When the current is too large, the constant current module causes the MOSFET tube to enter the linear region to work to limit the current passing through, thereby limiting the braking torque of the motor. Improving the simplicity, reliability and effectiveness of the vehicle sliding downhill control mode when the battery is disconnected.

[0011] Another invention object of the present invention application is to provide a low-speed electric vehicle slow slope control system, including a battery, a cart switch and a BLDC motor, and adopts the low-speed electric vehicle slow slope control method described in one of the above technical solutions. The normally open contact of the cart switch is electrically connected to the positive electrode of the power battery through the first voltage processing module and is electrically connected to the drain of the MOSFET tube through the first voltage processing module at the same time. The normally closed contact of the cart switch is electrically connected to the gate of the MOSFET tube through the third voltage processing module. The voltage processing module is electrically connected to the gate of the MOSFET tube. The MCU output 1 module is electrically connected to the gate of the MOSFET tube through the output processing 1 module. The MCU input 1 module is electrically connected to the MOSFET tube through the input processing 1 module. The gate of the T-tube is electrically connected, the gate of the MOSFET is electrically connected to the current acquisition module through a constant current module, forming a loop with the power ground. The source of the MOSFET is electrically connected to the current acquisition module through a constant current module, forming a loop with the power ground. The drain of the MOSFET is electrically connected to the normally closed contact NC of the relay. The relay drive port of the MCU is electrically connected to the relay coil drive through a relay drive circuit. The normally open contact NO of the relay is electrically connected to the positive pole of the power battery. A rectifier and filter circuit is connected in parallel between the relay switching contact and the power ground. The BLDC motor is electrically connected to the relay switching contact through the rectifier and filter circuit. The MCU pre-charge control port is electrically connected to the relay switching contact through a pre-charge circuit, and the pre-charge circuit is electrically connected to the positive pole of the power battery. In the event of a power outage or other abnormal shutdown of the control system, the vehicle can be effectively prevented from slowly rolling down a slope, avoiding the hidden safety risk of the vehicle rapidly rolling down a slope. In the event of a power outage or other abnormal shutdown of the control system, the vehicle can be effectively prevented from slowly rolling down a slope, avoiding the hidden safety risk of the vehicle rapidly rolling down a slope.

[0012] Preferably, the first voltage processing module includes a 1# voltage processing module and a 2# voltage processing module, and the second voltage processing module is a 3# voltage processing module. The normally open contact of the cart switch is electrically connected to the positive electrode of the power battery through the 1# voltage processing module, the normally open contact of the cart switch is electrically connected to the drain of the MOSFET tube through the 1# voltage processing module and the 2# voltage processing module in sequence, and the normally closed contact of the cart switch is electrically connected to the gate of the MOSFET tube through the 3# voltage processing module. This improves the stability, reliability and effectiveness of voltage processing in the cart control mode.

[0013] Preferably, the rectifier and filter circuit includes a three-phase half-bridge module and a first capacitor, which are electrically connected in parallel and have their positive terminals electrically connected to relay switching contacts. This improves the simplicity, stability, reliability, and effectiveness of the rectifier and filter for the BLDC motor's braking current.

[0014] The beneficial effects of the present invention are that when the control system is shut down due to power outages or other abnormalities, the vehicle can be effectively suppressed from slowly sliding down the slope, avoiding the hidden safety risks of low-speed electric vehicles sliding down the slope quickly. When the control system is shut down due to power outages or other abnormalities, the vehicle can be effectively suppressed from slowly sliding down the slope, avoiding the hidden safety risks of low-speed electric vehicles sliding down the slope quickly. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The diagram is a schematic diagram of the principle structure of a method for controlling a slow slope of a low-speed electric vehicle and a control system thereof according to the present invention. DETAILED DESCRIPTION

[0016] Example 1 Figure 1 In the embodiment shown, a method for controlling a low-speed electric vehicle to roll down a slope includes the following state roll down control modes: A1. Normal operating control mode: The MCU output 1 signal pulls the MOSFET gate low, turning off the MOSFET. The battery charges the bus capacitor, which is located on the bus. The relay drive circuit closes the relay contacts, connecting the battery to the bus through the relay. The low-speed electric vehicle is in normal operating condition. A2. Abnormal detection working control mode: The output signal of MCU output 1 is in the disabled state. If the MCU detects that the MCU input 1 signal detects that the cart switch is in the open state, it is determined that the MCU control system is in an abnormal state, and an alarm indication is issued through the alarm-related modules; A3. Cart control mode: After the MCU control system is shut down, if the external cart switch is turned to the off state, the MOSFET tube loses drive and is cut off, and the vehicle can be pushed normally; A4. In hill-climbing control mode with the battery online: After the MCU control system is shut down, the battery voltage drives the MOSFET to conduct, connecting the C contact of the relay to the NC contact. The back EMF of the BLDC motor (brushless DC motor) is transmitted through the rectifier and filter circuit to output a DC voltage to the C contact and NC contact of the relay, which then conducts to the MOSFET to form a current loop. The BLDC motor generates braking current, braking the motor and preventing the vehicle from rolling down the hill. If the current flowing through the MOSFET is too high, the MOSFET enters the linear region, limiting the current and thus limiting the motor's braking torque. A5. Hill-rolling control mode when the battery is disconnected: After the MCU control system is shut down, the BLDC motor's back EMF is rectified and filtered to output a DC voltage, driving the MOSFET to conduct, forming a current loop. The BLDC motor generates a braking current, braking the motor and preventing the vehicle from rolling down the hill. When the current is too high, the MOSFET enters the linear region to limit the current, thereby limiting the motor's braking torque.

[0017] The above step A1 includes the following steps: Step 1: MCU outputs 1 output signal, which is processed by output processing 1 to pull down the gate of MOSFET tube, and MOSFET tube is turned off; Step 2: The MCU pre-charge control output signal controls the pre-charge circuit to work, and the battery charges the bus capacitor CAP1. Step 3: After the voltage across CAP1 rises to a stable level, the MCU relay drive output signal drives the relay NO contact and C contact to close through the relay drive circuit, and the battery is connected to the busbar through the relay.

[0018] In the above step A1, MCU output 1 is output prohibited. If the cart switch is in the off-circuit state, the MCU detects the MCU input 1 signal and detects that the cart switch is in the off-circuit state. The system is abnormal, that is, an alarm indication is issued through the alarm-related module.

[0019] In step A4 above, after the MCU control system shuts down, the battery voltage is stepped down by voltage processing 1. After the push switch is closed, voltage processing 3 drives the MOSFET to conduct. The relay's C contact is connected to the NC contact. The BLDC motor's back EMF is rectified by a three-phase half-bridge and filtered by CAP1 to output a DC voltage. This voltage flows through the relay's C contact, the RELAY contact NC, the MOSFET, and current collection to GND, forming a current loop. The BLDC motor generates braking current, braking the motor and preventing the vehicle from rolling down the slope. When the current is excessive, the constant current module operates the MOSFET in its linear region to limit the current flow and, therefore, the motor's braking torque. When the MOSFET is turned on, the gate power consumption is low, resulting in a low-power system design.

[0020] In step A5 above, after the MCU control system shuts down, the BLDC motor's back EMF is filtered through a three-phase half-bridge rectifier and capacitor CAP1 to output a DC voltage. This voltage then passes through voltage processing 2, a closed push switch, and voltage processing 3 to turn on the MOSFET. This voltage then flows through RELAY contact C, RELAY contact NC, the MOSFET, and current collection to the power supply ground GND, forming a current loop. The BLDC motor generates braking current, braking the motor and preventing the vehicle from rolling down the slope. When the current is excessive, the constant current module causes the MOSFET to operate in its linear region to limit the current, thereby limiting the motor's braking torque.

[0021] Example 2 Figure 1In the embodiment shown, a low-speed electric vehicle slow-slope control system includes a battery, a cart switch and a BLDC motor, and adopts the low-speed electric vehicle slow-slope control method described in Example 1. The normally open contact of the cart switch is electrically connected to the positive electrode of the power battery through the first voltage processing module and is electrically connected to the drain of the MOSFET tube through the first voltage processing module at the same time. The normally closed contact of the cart switch is electrically connected to the gate of the MOSFET tube through the third voltage processing module, the voltage processing module is electrically connected to the gate of the MOSFET tube, the MCU output 1 module is electrically connected to the gate of the MOSFET tube through the output processing 1 module, and the MCU input 1 module is electrically connected to the gate of the MOSFET tube through the input processing 1 module. The gate of the MOSFET tube is electrically connected to the current acquisition module through the constant current module and forms a loop with the power ground. The source of the MOSFET tube is electrically connected to the current acquisition module through the constant current module and forms a loop with the power ground. The drain of the MOSFET tube is electrically connected to the normally closed contact NC of the relay. The MCU relay drive port is electrically connected to the relay coil drive through the relay drive circuit. The normally open contact NO of the relay is electrically connected to the positive electrode of the power battery. A rectifier filter circuit is connected in parallel between the relay conversion contact and the power ground. The BLDC motor is electrically connected to the relay conversion contact through the rectifier filter circuit. The MCU pre-charge control port is electrically connected to the relay conversion contact through the pre-charge circuit, and the pre-charge circuit is electrically connected to the positive electrode of the power battery. The first voltage processing module includes voltage processing module 1# and voltage processing module 2#, and the second voltage processing module is voltage processing module 3#. The normally open contact of the cart switch is electrically connected to the positive terminal of the power battery through voltage processing module 1#. One end of the cart switch is electrically connected to the drain of the MOSFET tube through voltage processing module 1# and voltage processing module 2#, respectively. The normally closed contact of the cart switch is electrically connected to the gate of the MOSFET tube through voltage processing module 3#. The rectifier and filter circuit includes a three-phase half-bridge module and a first capacitor. The three-phase half-bridge module and the first capacitor are electrically connected in parallel, and the positive terminals are both electrically connected to the relay switching contacts. The first capacitor is also known as busbar capacitor CAP1. Other aspects are the same as in Example 1. The voltage processing module, output processing module 1, input processing module 1, precharge circuit, constant current module, current acquisition module, relay drive circuit, and three-phase half-bridge circuit can be borrowed or referenced from the related circuits in the prior art. They only need to meet the requirements of the low-speed electric vehicle slow slope control method described in the present invention and will not be described in detail here.

Claims

1. A method for controlling a low-speed electric vehicle to roll down a slope, characterized in that The following state slope control modes are included: A1. Normal operating control mode: The MCU output 1 signal pulls the MOSFET gate low, turning off the MOSFET. The battery charges the bus capacitor, which is located on the bus. The relay drive circuit closes the relay contacts, connecting the battery to the bus through the relay. The low-speed electric vehicle is in normal operating condition. A2. Abnormal detection working control mode: The output signal of MCU output 1 is in the disabled state. If the MCU detects that the MCU input 1 signal detects that the cart switch is in the open state, it is determined that the MCU control system is in an abnormal state, and an alarm indication is issued through the alarm-related modules; A3. Cart control mode: After the MCU control system is shut down, if the external cart switch is turned to the off state, the MOSFET tube loses drive and is cut off, and the vehicle can be pushed normally; A4. In slope control mode with the battery online: After the MCU control system is shut down, the battery voltage drives the MOSFET to conduct, connecting the relay's C contact and NC contact. The BLDC motor's back EMF, passing through the rectifier and filter circuit, outputs a DC voltage to the relay's C contact and NC contact, which then conducts to the MOSFET, forming a current loop. The BLDC motor generates braking current, braking the motor and preventing the vehicle from rolling down the slope. If the current flowing through the MOSFET is too high, it enters its linear region, limiting the current and thus limiting the motor's braking torque. A5. Hill-rolling control mode when the battery is disconnected: After the MCU control system is shut down, the BLDC motor's back EMF is rectified and filtered to output a DC voltage, driving the MOSFET to conduct, forming a current loop. The BLDC motor generates a braking current, braking the motor and preventing the vehicle from rolling down the hill. When the current is too high, the MOSFET enters the linear region to limit the current, thereby limiting the motor's braking torque.

2. The method for controlling a low-speed electric vehicle to roll down a slope according to claim 1, wherein: The above step A1 includes the following steps: Step 1: MCU outputs 1 output signal, which is processed by output processing 1 to pull down the gate of MOSFET tube, and MOSFET tube is turned off; Step 2: The MCU pre-charge control output signal controls the pre-charge circuit to work, and the battery charges the bus capacitor CAP1. Step 3: After the voltage across CAP1 rises to a stable level, the MCU relay drive output signal drives the relay NO contact and C contact to close through the relay drive circuit, and the battery is connected to the busbar through the relay.

3. The method for controlling a low-speed electric vehicle to roll down a slope according to claim 1, wherein: In the above step A1, MCU output 1 is output prohibited. If the cart switch is in the off-circuit state, the MCU detects the MCU input 1 signal and detects that the cart switch is in the off-circuit state. The system is abnormal, that is, an alarm indication is issued through the alarm-related module.

4. The method for controlling a low-speed electric vehicle to roll down a slope according to claim 1, wherein: In step A4 above, after the MCU control system shuts down, the battery voltage is stepped down by voltage processing 1. After the push switch is closed, voltage processing 3 drives the MOSFET to conduct. The relay's C contact is connected to the NC contact. The BLDC motor's back EMF is rectified by a three-phase half-bridge and filtered by CAP1 to output a DC voltage. This voltage flows through the relay's C contact, the RELAY contact NC, the MOSFET, and current collection to GND, forming a current loop. The BLDC motor generates braking current, braking the motor and preventing the vehicle from rolling down the slope. When the current is excessive, the constant current module operates the MOSFET in its linear region to limit the current flow and, therefore, the motor's braking torque. When the MOSFET is turned on, the gate power consumption is low, resulting in a low-power system design.

5. The method for controlling a low-speed electric vehicle to roll down a slope according to claim 1, wherein: In step A5 above, after the MCU control system shuts down, the BLDC motor's back EMF is filtered through a three-phase half-bridge rectifier and capacitor CAP1 to output a DC voltage. This voltage then passes through voltage processing 2, a closed push switch, and voltage processing 3 to turn on the MOSFET. This voltage then flows through RELAY contact C, RELAY contact NC, the MOSFET, and current collection to the power supply ground GND, forming a current loop. The BLDC motor generates braking current, braking the motor and preventing the vehicle from rolling down the slope. When the current is excessive, the constant current module causes the MOSFET to operate in its linear region to limit the current, thereby limiting the motor's braking torque.

6. A low-speed electric vehicle slow-down control system, comprising a battery, a push switch, and a BLDC motor, characterized in that: The method for controlling the slow slope of a low-speed electric vehicle according to one of claims 1 to 5 is adopted, the normally open contact of the cart switch is electrically connected to the positive electrode of the power battery through the first voltage processing module and is electrically connected to the drain of the MOSFET tube through the first voltage processing module at the same time, the normally closed contact of the cart switch is electrically connected to the gate of the MOSFET tube through the third voltage processing module, the voltage processing module is electrically connected to the gate of the MOSFET tube, the MCU output 1 module is electrically connected to the gate of the MOSFET tube through the output processing 1 module, the MCU input 1 module is electrically connected to the gate of the MOSFET tube through the input processing 1 module, and the gate of the MOSFET tube is electrically connected to the gate of the MOSFET tube through the constant current module. The block is electrically connected to the current acquisition module and forms a loop with the power ground. The source of the MOSFET tube is electrically connected to the current acquisition module through the constant current module and forms a loop with the power ground. The drain of the MOSFET tube is electrically connected to the normally closed contact NC of the relay. The MCU relay drive port is electrically connected to the relay coil drive through the relay drive circuit. The normally open contact NO of the relay is electrically connected to the positive pole of the power battery. A rectifier and filter circuit is connected in parallel between the relay switching contact and the power ground. The BLDC motor is electrically connected to the relay switching contact through the rectifier and filter circuit. The MCU pre-charge control port is electrically connected to the relay switching contact through the pre-charge circuit, and the pre-charge circuit is electrically connected to the positive pole of the power battery.

7. The control system for a low-speed electric vehicle rolling down a slope according to claim 6, characterized in that: The first voltage processing module includes a 1# voltage processing module and a 2# voltage processing module, and the second voltage processing module adopts a 3# voltage processing module. The normally open contact of the cart switch is electrically connected to the positive pole of the power battery through the 1# voltage processing module, and the normally open contact of the cart switch is electrically connected to the drain of the MOSFET tube through the 1# voltage processing module and the 2# voltage processing module in turn. The normally closed contact of the cart switch is electrically connected to the gate of the MOSFET tube through the 3# voltage processing module.

8. The control system for a low-speed electric vehicle rolling down a slope according to claim 6, characterized in that: The rectifier and filter circuit includes a three-phase half-bridge module and a first capacitor. The three-phase half-bridge module and the first capacitor are electrically connected in parallel, and the positive terminals are both electrically connected to the relay switching contacts.

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