Sidewalk sweeper electric drive system and control method thereof

Abstract

The application discloses a sidewalk sweeper electric driving system and a control method thereof, wherein a power battery is used for providing a DC power supply, and a working voltage is 48-90V; a power supply end of a signal conversion unit is connected with the power battery; signal output ends of the signal conversion unit are respectively connected with control signal input ends of a walking motor controller and a fan motor controller; signal input ends of the signal conversion unit are respectively connected with feedback signal output ends of the walking motor controller and the fan motor controller; and the signal conversion unit is connected with a vehicle control unit through a CAN bus network; the application solves a ground level difference between an upper-mounted system and a vehicle body control system, directly collects and controls analog voltages of the walking motor controller and the fan motor controller through the signal conversion unit, and realizes information interaction and real-time control among the walking motor controller, the fan motor controller and the vehicle control unit.

Description

Technical Field

[0001] This invention belongs to the field of new energy vehicle control technology, specifically an electric drive system and control method for a sidewalk sweeper. Background Technology

[0002] The electric sidewalk sweeper integrates sweeping and washing functions, and has functions such as water spraying, sweeping, and dust removal. It will not generate dust during sweeping, nor will it accumulate water or dust. It can sweep up all kinds of garbage on narrow sidewalks and suck them into the garbage bin at any time, solving the problem of cleaning up garbage such as dust, fallen leaves, and stones.

[0003] The electric sidewalk sweeper has a sweeping width of approximately 1.5 meters and a working efficiency of 10,000 square meters per hour, equivalent to the cleaning efficiency of 10 manual laborers. When its walking system is electrically driven, it achieves environmental friendliness without secondary pollution. In addition to the walking system, the sidewalk sweeper's operating system (superstructure) can also be electrically driven. The main components of the superstructure include left and right sweeping disc motors and a blower motor, which respectively perform sweeping and garbage collection. Its power supply is a 48-90V battery, and the operating system is controlled by the VCU module of the vehicle control unit. Since most of the left and right sweeping disc motors and blower motors of the sidewalk sweeper use batteries as their power source, analog voltage is used for speed control, and their operating status feedback is also 0-24V DC voltage. Meanwhile, since most of the vehicle's running system uses 12V lead-acid batteries as power supply, and the power batteries are all ungrounded systems, the ground of the 12V lead-acid battery in the running system cannot be shared with the ground of the power battery in the superstructure system, resulting in a ground level mismatch problem in signal transmission between the superstructure operating system and the vehicle running system.

[0004] Since the power supply for the drive motor controller and fan motor controller is provided by the power battery, to prevent insulation degradation between the high-voltage circuit of the power battery and the vehicle chassis, which could affect the normal operation of low-voltage electrical systems, create vehicle safety hazards, and endanger the driver's personal safety, the power battery system adopts an ungrounded system. This means there is no direct electrical connection between the high-voltage system's ground and the vehicle's low-voltage system's ground. The power supply for the internal control circuits of the drive motor controller and fan motor controller is provided by the power battery system. The signal grounds of both the drive motor controller and fan motor controller are relative to the power battery's ground. If the input and output signals of the drive motor controller and fan motor controller are directly connected to the vehicle control unit, it would short-circuit the power battery's ground with the vehicle's low-voltage system's ground, creating a safety hazard. The BMS system will then indicate a high-voltage system insulation fault, preventing the vehicle control system from functioning properly. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an electric drive system and control method for a sidewalk sweeper. By directly acquiring and controlling the analog voltage of the walking motor controller and the fan motor controller through a signal conversion unit, information interaction and real-time control between the walking motor controller, the fan motor controller, and the vehicle control unit are realized, thus solving the problem of ground level difference between the superstructure system and the vehicle body control system.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] In a first aspect, the present invention provides an electric drive system for a sidewalk sweeper, the system comprising a power battery, a walking motor controller, a fan motor controller, left and right sweeping disc motor controllers, a signal conversion unit, and a vehicle control unit;

[0008] The power battery is used to provide DC power, and its operating voltage is 48-90V;

[0009] The power supply terminal of the walking motor controller is connected to the power battery, and the control signal input terminal and feedback signal output terminal of the walking motor controller are respectively connected to the signal conversion unit.

[0010] The power supply terminal of the wind turbine motor controller is connected to the power battery, and the control signal input terminal and feedback signal output terminal of the wind turbine motor controller are respectively connected to the signal conversion unit.

[0011] The power supply terminals of the left and right sweeping disc motor controllers are respectively connected to the power battery, and the control signal terminals of the left and right sweeping disc motor controllers are respectively connected to the vehicle control unit.

[0012] The power supply terminal of the signal conversion unit is connected to the power battery, the signal output terminal of the signal conversion unit is connected to the control signal input terminal of the walking motor controller and the fan motor controller respectively, the signal input terminal of the signal conversion unit is connected to the feedback signal output terminal of the walking motor controller and the fan motor controller respectively, and the signal conversion unit is connected to the vehicle control unit through the CAN bus network.

[0013] The vehicle control unit is also connected to an external vehicle control switch via a CAN bus network, and is powered by a 12V low-voltage battery.

[0014] As a further improved technical solution of the present invention, the walking motor controller is a motor driver in the vehicle walking system and is connected to the vehicle driving system's driving motor for control. The signal output terminal of the signal conversion unit inputs a 0-5V DC voltage to the signal input terminal of the walking motor controller to adjust the speed of the walking motor. The signal output terminal of the electric walking motor driver inputs a 0-24V DC voltage to the signal input terminal of the signal conversion unit to characterize the current speed of the walking motor.

[0015] As a further improvement of the present invention, the fan motor controller is a motor driver in the upper system and is connected to the fan in the upper system for control. The signal output terminal of the signal conversion unit inputs a DC voltage of 0 to 5V to the signal input terminal of the fan motor driver to adjust the speed of the fan. The signal output terminal of the fan controller inputs a DC voltage of 0 to 24V to the signal input terminal of the signal conversion unit to characterize the current actual speed of the fan.

[0016] As a further improvement of the present invention, the CAN communication interface of the signal conversion unit communicates with the vehicle control unit through the CAN bus network, and parses the control signals of the vehicle control unit to obtain the corresponding output voltage, which is used to control the working status of the travel motor controller and the fan motor controller respectively. At the same time, the working status of the travel motor controller and the fan motor controller is transmitted to the vehicle control unit through the CAN bus network.

[0017] As a further improvement of the present invention, the signal conversion unit includes built-in multi-channel ADC sampling units F1 and F2, analog output units V1 and V2, a microcontroller, and a power supply circuit. The analog output units V1 and V2 each include multiple 12-bit DAC conversion modules, generating an output voltage of 0-5V to control the rotational speed of the walking motor controller and the fan motor controller. The multi-channel ADC sampling units F1 and F2 respectively acquire the output voltages of the walking motor controller and the fan motor controller, with input voltage values ​​ranging from 0 to 1 / 2 of the power battery's operating voltage. These values ​​are then converted into the actual rotational speed values ​​of the walking motor controller and the fan motor controller through their respective output voltage values.

[0018] As a further improvement of the present invention, the signal conversion unit further includes an isolated CAN transceiver, used to receive CAN information commands from the vehicle control unit's drive motor controller and fan motor controller, respectively. The CAN information commands include the required speed commands and rotation direction commands from the drive motor controller and fan motor controller. After receiving and parsing the required speed commands, the signal conversion unit converts them into corresponding analog voltage control quantities. Then, the DAC conversion module generates corresponding analog voltages and inputs them to the drive motor controller and fan motor controller, respectively, and sends rotation direction commands to the drive motor controller. At the same time, the signal conversion unit receives the speed feedback signals from the drive motor controller and fan motor controller, converts them into the current actual speed, and sends them to the vehicle control unit through the CAN bus network.

[0019] As a further improved technical solution of the present invention, the left and right sweeping disc motor controllers are motor drivers in the upper structure system, respectively connected to the left and right sweeping disc motors for control. The control terminal of the vehicle control unit is connected to the control signal terminal of the left and right sweeping disc motor controllers through control lines, and obtains the working status of the left and right sweeping disc motors.

[0020] Secondly, the present invention also provides a control method for an electric drive system of a sidewalk sweeper, the method comprising the following steps:

[0021] (1) The signal output circuit of the signal conversion unit is an analog signal output. Its output voltage variation range is designed to be 0 to 5V DC voltage. The maximum output voltage is designed to be the control voltage required for the walking motor controller and the fan motor controller to reach or exceed the maximum speed. That is, the output voltage of the analog output units V1 and V2 is greater than or equal to 4.8V. When the signal conversion unit receives the required speed command of the walking motor controller and the fan motor controller sent by the vehicle control unit through the isolated CAN transceiver, the microcontroller parses the required speed command and converts it into the control voltage required for the walking motor controller and the fan motor controller to reach the speed. The microcontroller then drives two independent DAC converters through the external SPI interface circuit. After the two DAC converters generate the required DC voltage values ​​of the walking motor controller and the fan motor controller respectively, they finally output 0 to 5V DC voltage through the voltage follower and transmit it to the signal input terminal of the walking motor controller and the fan motor controller to drive the walking motor controller and the fan motor controller to work at the corresponding required speed.

[0022] (2) The signal acquisition circuit of the signal conversion unit is an analog input acquisition. The voltage variation range of the multi-channel ADC sampling units F1 and F2 is 0 to 24V DC voltage. When the walking motor controller and the fan motor controller are in working state, the actual speed is directly proportional to their output voltage. The actual maximum output voltage is designed to correspond to the maximum speed of the walking motor and the fan motor. After the output voltage is transmitted to the signal conversion unit, it is divided by the internal voltage divider circuit and transmitted to the ADC sampling port of the microcontroller through the voltage follower. The microcontroller converts the sampled voltage into the actual speed of the walking motor and the fan motor respectively, and finally sends the actual speed information to the vehicle control unit through the CAN bus network.

[0023] As a further improvement of the present invention, the power supply circuit is used to provide a stable 5V DC voltage to provide working power for the microcontroller, SPI interface circuit and CAN transceiver inside the signal conversion unit. The power supply circuit consists of an integrated switching regulator U2 and peripheral circuits. The integrated switching regulator U2 supports wide voltage input. The peripheral circuit integrates soft start and over-temperature protection circuits. The peripheral circuit detects the inductor current through resistor R7 and detects the output feedback voltage through resistors R1, R2, R3 and R4 respectively, so as to improve the stability of the output DC voltage.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. This invention adds a signal conversion unit between the high and low voltage systems for control. The signal conversion unit is powered by the power battery. The power ground of the signal conversion unit, the travel motor controller, and the fan motor controller are all connected to the ground terminal of the power battery, achieving equipotential bonding among them. The signal conversion unit completes signal acquisition and control voltage output. An isolated CAN transceiver is used between the signal conversion unit and the vehicle control unit to exchange communication information via CAN messages. Because the isolated CAN transceiver uses opto-isolation or magneto-electric isolation for signal transmission, there is no direct electrical physical connection between the signal and the power battery, thus achieving information transmission and solving the ground level difference problem between the superstructure system and the vehicle body control system.

[0026] 2. This invention connects the fan motor controller and the travel motor controller via a signal conversion unit. The signal conversion unit exchanges information with the vehicle control unit through a CAN bus network and then generates different output voltages to control the operation of the travel motor controller and the fan motor controller respectively. When the fan motor controller and the travel motor controller are working, their operating status is transmitted to the signal conversion unit in the form of voltage. The signal conversion unit collects the speed feedback signal, converts it into the current actual speed, and transmits it to the vehicle control unit, thus realizing two-way information interaction. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a system schematic diagram of the electric drive system for the sidewalk sweeper of the present invention;

[0029] Figure 2 This is a schematic diagram of the signal conversion unit of the present invention;

[0030] Figure 3 This is a circuit diagram of the power supply circuit inside the signal conversion unit of the present invention. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present invention.

[0032] Example 1:

[0033] Reference Figure 1-2 This embodiment discloses an electric drive system for a sidewalk sweeper, which includes a power battery, a walking motor controller, a fan motor controller, left and right sweeping disc motor controllers, a signal conversion unit, and a vehicle control unit;

[0034] The power battery is used to provide DC power, and its operating voltage is 48-90V;

[0035] The power supply terminal of the walking motor controller is connected to the power battery, and the control signal input terminal and feedback signal output terminal of the walking motor controller are respectively connected to the signal conversion unit.

[0036] The power supply terminal of the wind turbine motor controller is connected to the power battery, and the control signal input terminal and feedback signal output terminal of the wind turbine motor controller are respectively connected to the signal conversion unit.

[0037] The power supply terminals of the left and right sweeping disc motor controllers are connected to the power battery, and the control signal terminals of the left and right sweeping disc motor controllers are connected to the vehicle control unit. The left and right sweeping disc motor controllers are motor drivers in the upper structure system, and are connected to the left and right sweeping disc motors respectively. The control terminals S1 and S2 of the vehicle control unit are connected to the control signal terminals S1 and S2 of the left and right sweeping disc motor controllers through control lines, and obtain the working status of the left and right sweeping disc motors.

[0038] The power supply terminal of the signal conversion unit is connected to the power battery. The signal output terminal of the signal conversion unit is connected to the control signal input terminals of the walking motor controller and the fan motor controller, respectively. The signal input terminal of the signal conversion unit is connected to the feedback signal output terminals of the walking motor controller and the fan motor controller, respectively. The signal conversion unit is connected to the vehicle control unit through the CAN bus network.

[0039] The vehicle control unit is also connected to an external vehicle control switch via a CAN bus network, and is powered by a 12V low-voltage battery.

[0040] In this embodiment, the walking motor controller is a motor driver in the vehicle walking system and is connected to the vehicle driving system's driving motor for control. The signal output terminal of the signal conversion unit inputs a 0-5V DC voltage to the signal input terminal of the walking motor controller to adjust the speed of the walking motor. The signal output terminal of the electric walking motor driver inputs a 0-24V DC voltage to the signal input terminal of the signal conversion unit to characterize the current speed of the walking motor.

[0041] The fan motor controller is the motor driver in the upper system and is connected to the fan in the upper system for control. The fan is used to generate strong suction to suck various types of garbage into the garbage bin. The signal output terminal of the signal conversion unit inputs a 0-5V DC voltage to the signal input terminal of the fan motor driver to adjust the fan speed; the signal output terminal of the fan controller inputs a 0-24V DC voltage to the signal input terminal of the signal conversion unit to indicate the current actual fan speed.

[0042] The CAN communication interface of the signal conversion unit communicates with the vehicle control unit through the CAN bus network, and parses the control signals of the vehicle control unit to obtain the corresponding output voltage, which is used to control the working status of the travel motor controller and the fan motor controller respectively. At the same time, the working status of the travel motor controller and the fan motor controller is transmitted to the vehicle control unit through the CAN bus network.

[0043] Reference Figure 1The signal conversion unit includes built-in multi-channel ADC sampling units F1 and F2, analog output units V1 and V2, a microcontroller, a power supply circuit, and an isolated CAN transceiver. The analog output units V1 and V2 each include multiple 12-bit DAC conversion modules, generating 0-5V output voltages to control the speed of the walking motor controller and the fan motor controller. The multi-channel ADC sampling units F1 and F2 respectively acquire the output voltages of the walking motor controller and the fan motor controller, with input voltage values ​​ranging from 0 to 1 / 2 of the power battery's operating voltage. These values ​​are then converted into the actual speed values ​​of the current walking motor controller and the fan motor controller through their respective output voltage values.

[0044] The isolated CAN transceiver is used to receive CAN information commands from the vehicle control unit's drive motor controller and fan motor controller, respectively. The CAN information commands include the required speed commands and rotation direction commands from the drive motor controller and fan motor controller. After receiving the required speed commands, the signal conversion unit parses them and converts them into corresponding analog voltage control quantities. Then, the DAC conversion module generates corresponding analog voltages and inputs them to the drive motor controller and fan motor controller respectively, and sends rotation direction commands to the drive motor controller. At the same time, the signal conversion unit receives the speed feedback signals from the drive motor controller and fan motor controller, converts them into the current actual speed, and sends them to the vehicle control unit through the CAN bus network.

[0045] The power supply circuit provides a stable 5V DC voltage to power the microcontroller, SPI interface circuit, and CAN transceiver within the signal conversion unit. The power supply circuit consists of an integrated switching regulator U2 and peripheral circuitry. The integrated switching regulator U2 supports a wide input voltage range. The peripheral circuitry integrates soft-start and over-temperature protection circuits, and features output short-circuit protection and current limiting protection. The maximum input voltage VBAT can reach 100V. The peripheral circuitry uses resistor R7 to detect the inductor current and resistors R1, R2, R3, and R4 to detect the output feedback voltage, thereby improving the stability of the output DC voltage.

[0046] Example 2:

[0047] Reference Figure 2-3 This embodiment discloses a control method for an electric drive system of a sidewalk sweeper, the method comprising the following steps:

[0048] (1) The signal output circuit of the signal conversion unit is an analog signal output. Its output voltage variation range is designed to be 0 to 5V DC voltage. The maximum output voltage is designed to be the control voltage required for the walking motor controller and the fan motor controller to reach or exceed the maximum speed. That is, the output voltage of the analog output units V1 and V2 is greater than or equal to 4.8V. When the signal conversion unit receives the required speed command of the walking motor controller and the fan motor controller sent by the vehicle control unit through the isolated CAN transceiver, the microcontroller parses the required speed command and converts it into the control voltage required for the walking motor controller and the fan motor controller to reach the speed. The microcontroller then drives two independent DAC converters through the external SPI interface circuit. After the two DAC converters generate the required DC voltage values ​​of the walking motor controller and the fan motor controller respectively, they finally output 0 to 5V DC voltage through the voltage follower and transmit it to the signal input terminal of the walking motor controller and the fan motor controller to drive the walking motor controller and the fan motor controller to work at the corresponding required speed.

[0049] (2) The signal acquisition circuit of the signal conversion unit is an analog input acquisition. The voltage variation range of the multi-channel ADC sampling units F1 and F2 is 0 to 24V DC voltage. When the walking motor controller and the fan motor controller are in working state, the actual speed is directly proportional to their output voltage. The actual maximum output voltage is designed to correspond to the maximum speed of the walking motor and the fan motor. After the output voltage is transmitted to the signal conversion unit, it is divided by the internal voltage divider circuit and transmitted to the ADC sampling port of the microcontroller through the voltage follower. The microcontroller converts the sampled voltage into the actual speed of the walking motor and the fan motor respectively, and finally sends the actual speed information to the vehicle control unit through the CAN bus network.

[0050] The above embodiments are only used to illustrate the technical methods of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical methods of the present invention without departing from the spirit and scope of the technical methods of the present invention.

Claims

1. A control method for an electric drive system of a sidewalk sweeper, characterized in that, The electric drive system includes a power battery, a walking motor controller, a fan motor controller, left and right sweeping disc motor controllers, a signal conversion unit, and a vehicle control unit; The method includes the following steps: (1) The signal output circuit of the signal conversion unit is an analog signal output. Its output voltage variation range is designed to be 0 to 5V DC voltage. The maximum output voltage is designed to be the control voltage required for the walking motor controller and the fan motor controller to reach or exceed the maximum speed. That is, the output voltage of the analog output units V1 and V2 is greater than or equal to 4.8V. When the signal conversion unit receives the required speed command of the walking motor controller and the fan motor controller sent by the vehicle control unit through the isolated CAN transceiver, the microcontroller parses the required speed command and converts it into the control voltage required for the walking motor controller and the fan motor controller to reach the speed. The microcontroller then drives two independent DAC converters through the external SPI interface circuit. After the two DAC converters generate the required DC voltage values ​​of the walking motor controller and the fan motor controller respectively, they finally output 0 to 5V DC voltage through the voltage follower and transmit it to the signal input terminal of the walking motor controller and the fan motor controller to drive the walking motor controller and the fan motor controller to work at the corresponding required speed. (2) The signal acquisition circuit of the signal conversion unit is an analog input acquisition. The voltage variation range of the multi-channel ADC sampling units F1 and F2 is 0 to 24V DC voltage. When the walking motor controller and the fan motor controller are in working state, the actual speed is directly proportional to their output voltage. The actual maximum output voltage is designed to correspond to the maximum speed of the walking motor and the fan motor. After the output voltage is transmitted to the signal conversion unit, it is divided by the internal voltage divider circuit and transmitted to the ADC sampling port of the microcontroller through the voltage follower. The microcontroller converts the sampled voltage into the actual speed of the walking motor and the fan motor respectively, and finally sends the actual speed information to the vehicle control unit through the CAN bus network.

2. The control method for an electric drive system of a sidewalk sweeper according to claim 1, characterized in that: The power battery is used to provide DC power, and its operating voltage is 48-90V; The power supply terminal of the walking motor controller is connected to the power battery, and the control signal input terminal and feedback signal output terminal of the walking motor controller are respectively connected to the signal conversion unit. The power supply terminal of the wind turbine motor controller is connected to the power battery, and the control signal input terminal and feedback signal output terminal of the wind turbine motor controller are respectively connected to the signal conversion unit. The power supply terminals of the left and right sweeping disc motor controllers are respectively connected to the power battery, and the control signal terminals of the left and right sweeping disc motor controllers are respectively connected to the vehicle control unit. The power supply terminal of the signal conversion unit is connected to the power battery, the signal output terminal of the signal conversion unit is connected to the control signal input terminal of the walking motor controller and the fan motor controller respectively, the signal input terminal of the signal conversion unit is connected to the feedback signal output terminal of the walking motor controller and the fan motor controller respectively, and the signal conversion unit is connected to the vehicle control unit through the CAN bus network. The vehicle control unit is also connected to an external vehicle control switch via a CAN bus network, and is powered by a 12V low-voltage battery.

3. The control method for an electric drive system of a sidewalk sweeper according to claim 2, characterized in that: The walking motor controller is a motor driver in the vehicle walking system and is connected to the vehicle driving system's driving motor for control. The signal output terminal of the signal conversion unit inputs a 0-5V DC voltage to the signal input terminal of the walking motor controller to adjust the speed of the walking motor. The signal output terminal of the electric walking motor driver inputs a 0-24V DC voltage to the signal input terminal of the signal conversion unit to characterize the current speed of the walking motor.

4. The control method for an electric drive system of a sidewalk sweeper according to claim 1, characterized in that, The fan motor controller is a motor driver in the upper system and is connected to the fan in the upper system for control. The signal output terminal of the signal conversion unit inputs a DC voltage of 0-5V to the signal input terminal of the fan motor driver to adjust the fan speed. The signal output terminal of the fan controller inputs a DC voltage of 0-24V to the signal input terminal of the signal conversion unit to characterize the current actual fan speed.

5. The control method for an electric drive system of a sidewalk sweeper according to claim 1, characterized in that, The CAN communication interface of the signal conversion unit communicates with the vehicle control unit through the CAN bus network, and parses the control signals of the vehicle control unit to obtain the corresponding output voltage, which is used to control the working status of the travel motor controller and the fan motor controller respectively. At the same time, the working status of the travel motor controller and the fan motor controller is transmitted to the vehicle control unit through the CAN bus network.

6. The control method for an electric drive system of a sidewalk sweeper according to claim 5, characterized in that, The signal conversion unit includes built-in multi-channel ADC sampling units F1 and F2, analog output units V1 and V2, a microcontroller, and a power supply circuit. The analog output units V1 and V2 each include multiple 12-bit DAC conversion modules, generating an output voltage of 0-5V to control the speed of the walking motor controller and the fan motor controller. The multi-channel ADC sampling units F1 and F2 respectively acquire the output voltages of the walking motor controller and the fan motor controller, with input voltage values ​​ranging from 0 to 1 / 2 of the power battery's operating voltage. These values ​​are then converted into the actual speed values ​​of the current walking motor controller and the fan motor controller through their respective output voltage values.

7. The control method for an electric drive system of a sidewalk sweeper according to claim 6, characterized in that, The signal conversion unit also includes an isolated CAN transceiver, used to receive CAN information commands from the vehicle control unit's drive motor controller and fan motor controller, respectively. The CAN information commands include the required speed commands and rotation direction commands from the drive motor controller and fan motor controller. After receiving and parsing the required speed commands, the signal conversion unit converts them into corresponding analog voltage control quantities. Then, the DAC conversion module generates corresponding analog voltages and inputs them to the drive motor controller and fan motor controller, respectively, and sends rotation direction commands to the drive motor controller. At the same time, the signal conversion unit receives the speed feedback signals from the drive motor controller and fan motor controller, converts them into the current actual speed, and sends them to the vehicle control unit via the CAN bus network.

8. The control method for an electric drive system of a sidewalk sweeper according to claim 1, characterized in that, The left and right sweeping disc motor controllers are motor drivers in the upper structure system, respectively connected to the left and right sweeping disc motors. The control terminal of the vehicle control unit is connected to the control signal terminal of the left and right sweeping disc motor controllers through control lines, and obtains the working status of the left and right sweeping disc motors.

9. The control method for an electric drive system of a sidewalk sweeper according to claim 6, characterized in that, The power supply circuit provides a stable 5V DC voltage to power the microcontroller, SPI interface circuit, and CAN transceiver inside the signal conversion unit. The power supply circuit consists of an integrated switching regulator U2 and peripheral circuits. The integrated switching regulator U2 supports wide voltage input. The peripheral circuits integrate soft-start and over-temperature protection circuits. The peripheral circuits detect inductor current through resistor R7 and output feedback voltage through resistors R1, R2, R3, and R4 to improve the stability of the output DC voltage.

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