Environment-friendly single-power electric driving system for engineering walking machinery

Abstract

The invention discloses an environment-friendly single-power electric driving system for engineering walking machinery. Relates to the field of engineering walking machinery such as automobiles, engineering special automobiles, engineering machinery, agricultural machinery and the like, and comprises a variable-frequency generator set, an electric energy conversion unit, a walking driving motor, an operation power supply interface and a system controller, the system controller has two working modes: in a running mode, an electronic throttle of a unit prime mover is used for controlling the generator set to run at a variable speed, and the electric energy conversion unit is used for driving the walking motor to realize stepless variable speed running of the chassis; in the operation mode, the cruise constant-speed switch controls the generator set to operate at a constant speed, and directly outputs constant-frequency and constant-voltage alternating current to supply power to upper equipment; according to the invention, the efficient engine meeting the emission standard of national VI or above is used as a prime motor, and the generator set formed by matching the efficient engine with the generator is used as power of electric engineering walking machinery, so that the requirement of environmental protection of the whole vehicle can be met without additionally matching high-standard environment-friendly emission equipment.

Description

Technical Field

[0001] This invention relates to electric drive technology for electric engineering vehicles and engineering machinery such as construction machinery and agricultural machinery, specifically to an electric drive system that integrates driving and operation functions for automobiles, engineering vehicles, construction machinery, agricultural machinery and other mobile machinery. Background Technology

[0002] In the existing technology, most engineering mobile machinery is modified by installing a set of working equipment on the chassis. The engine of the chassis of the mobile machinery serves as the driving power, and the working equipment on the upper body also needs to be equipped with a power source to drive the working equipment. Therefore, general engineering mobile machinery is so-called "dual power".

[0003] In this type of "dual-power" engineering mobile machinery, the chassis engine runs when heading to the construction site, and the engine or generator set of the working equipment starts working after arriving at the construction site, resulting in low power utilization. In addition, due to production cost limitations, it is almost impossible for conventional "dual-power" mobile machinery to simultaneously match the mobile engine and the superstructure power source to meet the high standards of environmental protection emission requirements. Therefore, it is imperative to propose a "single-power" drive system that uses an environmentally friendly variable frequency generator set to unify driving and operation. Summary of the Invention

[0004] The purpose of this invention is to provide an environmentally friendly single-power electric drive system for engineering mobile machinery, in order to solve the problem that in the prior art, the emission standards of the prime movers matched with generator sets are generally low (such as China III and China IV standards), which makes it difficult for mobile machinery based on them to meet the current national environmental protection requirements.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an environmentally friendly single-power electric drive system for engineering mobile machinery, comprising:

[0006] A variable frequency generator set consists of a direct connection between the engine body and the generator body.

[0007] The power conversion unit has its input terminal connected to the output terminal of the generator body;

[0008] The walking drive unit includes a walking drive motor, wherein the power input terminal of the walking drive motor is connected to the output terminal of the power conversion unit;

[0009] The power supply unit is used to connect the working motor;

[0010] The system controller is connected to the engine body, generator body, power conversion unit and driver operation unit respectively;

[0011] The system controller is configured to have at least two operating modes:

[0012] In the first working mode, the engine and generator are controlled by electronic throttle to operate synchronously at different speeds, and the drive motor is driven by AC power output from the power conversion unit through frequency conversion and voltage conversion.

[0013] In the second operating mode, the cruise control switch is used to control the engine body and generator body to operate stably at the rated speed, so that the generator body outputs AC power with a fixed frequency and voltage, and supplies power to the working motor through the working power supply unit.

[0014] Furthermore, the system controller includes a central controller, an inverter circuit driver, an engine speed controller, and an engine cruise control controller;

[0015] The driver control unit includes an electronic throttle and a cruise control switch;

[0016] In the first operating mode, the engine speed controller adjusts the engine speed according to the electronic throttle signal; in the second operating mode, the engine cruise control controller locks the engine speed according to the cruise control switch signal.

[0017] Furthermore, the power conversion unit includes a high-frequency transformer, a rectifier, a filter capacitor, and an inverter connected in sequence; the input end of the high-frequency transformer is connected to the generator body, and the output end of the inverter is connected to the walking drive motor through a walking motor switch.

[0018] Furthermore, it also includes a current detector, which is installed in the drive circuit between the inverter and the walking drive motor; the walking drive motor is equipped with a walking motor Hall angle sensor;

[0019] The central controller is connected to the electronic throttle, the Hall angle sensor of the travel motor, and the current detector signal. It is used to perform vector calculations based on the received signals and control the inverter through the inverter circuit driver.

[0020] Furthermore, the output terminal of the generator body is also connected to a generator speed sensor, which is used to feed back the speed signal to the engine cruise control controller.

[0021] Furthermore, the working power supply unit includes a working motor switch connected to the output end of the generator body, and the output end of the working motor switch constitutes a working power supply interface.

[0022] Furthermore, the generator body is a high-speed permanent magnet synchronous generator.

[0023] Furthermore, the walking drive motor is a permanent magnet synchronous motor.

[0024] Furthermore, the engine body is an internal combustion engine or a gas-fueled engine that meets China VI or higher emission standards.

[0025] Furthermore, the working power supply unit includes a working motor switch connected to the output terminal of the generator body;

[0026] The central controller is connected to the generator speed sensor, the work motor switch, and the cruise control switch, respectively. In the second working mode, it controls the engine speed to reach the rated value based on the feedback from the generator speed sensor and controls the work motor switch to close.

[0027] Compared with the prior art, the electric drive system for engineering mobile machinery provided by the present invention has the following beneficial effects:

[0028] 1. This invention uses a high-efficiency engine that meets the China VI emission standard or above as the prime mover, and the environmentally friendly generator set composed of the engine and the generator provides power for electric engineering mobile machinery. The environmental requirements of the whole vehicle can be met without the need for additional high-standard environmental emission equipment.

[0029] 2. By adopting a high-speed permanent magnet generator, the present invention features high speed, high power density, and short axial dimension, resulting in a very compact generator set structure that is easy to arrange flexibly on a mobile machinery chassis, freeing up valuable space for installing larger capacity superstructure equipment.

[0030] 3. This invention achieves AC power output of "variable frequency and variable voltage" and "fixed frequency and fixed voltage" through dual-mode control of "variable speed power generation and travel" and "fixed speed power generation and operation", thereby achieving the purpose of continuously variable speed travel of the chassis and driving the operation of electric engineering walking mechanical construction equipment;

[0031] 4. This invention adopts an electric drive method based on vector control for walking drive, combined with engine speed regulation, which can realize smooth and powerful stepless speed change of walking machinery, large low-speed torque, wide speed adjustment range, and better handling performance than traditional mechanical transmission or hydraulic transmission. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0033] Figure 1 This is an electrical schematic diagram of an electric drive system powered by an environmentally friendly variable frequency generator set for mobile machinery, provided in an embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 1. Engine body; 2. Generator body; 3. High-frequency transformer; 4. Rectifier; 5. Filter capacitor; 6. Inverter; 7. Electronic throttle; 8. Cruise control switch; 9. Generator speed sensor; 10. Central controller; 11. Inverter circuit driver; 12. Engine speed controller; 13. Engine cruise control controller; 14. Travel motor switch; 15. Travel drive motor; 16. Travel motor Hall angle sensor; 17. Work motor switch; 18. Work motor; 19. Current detector. Detailed Implementation

[0036] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0037] As attached Figure 1 As shown:

[0038] This invention provides an environmentally friendly electric drive system for engineering mobile machinery, including a power unit, an energy conversion unit, a walking drive unit, a work power supply unit, and a system controller. The units work together to achieve a unified power supply for walking and working.

[0039] The power unit consists of an engine body 1 and a generator body 2 rigidly connected directly. Both are coaxially arranged and mounted on a dedicated shock-absorbing unit bracket on the vehicle frame beam. The bracket uses elastic rubber pads to connect to the chassis, effectively absorbing vibrations generated during generator operation and reducing the impact on the overall vehicle structure. Engine body 1 is a vehicle internal combustion engine or gas-fueled engine that meets China VI or higher emission standards, and its power output characteristics are matched with the high-speed generator. Generator body 2 is a high-speed permanent magnet synchronous generator with a rated speed of not less than 3000 rpm. Depending on the vehicle layout requirements, a radial permanent magnet synchronous motor or an axial permanent magnet synchronous motor can be selected. Its rotor uses a permanent magnet structure, eliminating the need for excitation windings, and offers advantages such as high efficiency, high power density, and compact axial dimensions. It can be directly connected to engine body 1.

[0040] The power conversion unit includes a high-frequency transformer 3, a rectifier 4, a filter capacitor 5, and an inverter 6 connected in sequence. All components are integrated and installed in a waterproof and dustproof electrical control box, which is fixed to the reserved installation area on the chassis and has good heat dissipation performance and vibration resistance. The high-frequency transformer 3 uses a high-frequency ferrite core material. Its primary input terminal is connected to the output terminal of the generator body 2 via a large-section copper core cable, and its secondary output terminal is connected to the rectifier 4. Its function is to reduce the high-frequency AC voltage output by the generator body 2 to a voltage level suitable for subsequent rectification and filtering, while achieving electrical isolation. The rectifier 4 adopts a three-phase full-bridge rectifier topology and is composed of high-power diodes, which can convert the stepped-down AC power into DC power. The filter capacitor 5 uses a combination of electrolytic capacitors and film capacitors. The electrolytic capacitors are responsible for large-capacity energy storage, and the film capacitors suppress high-frequency ripple, together forming a low-ripple DC bus to provide a stable DC power supply for the inverter 6. The inverter 6 uses IGBT power modules to form a three-phase full-bridge inverter topology, which has high-frequency switching characteristics and high current output capability. Its drive signal is provided by the inverter circuit driver 11.

[0041] The driving unit includes a driving motor 15, a driving motor switch 14, a driving motor Hall angle sensor 16, and a mechanical transmission mechanism. The driving motor 15 is a permanent magnet synchronous motor, whose rated power matches the vehicle's traction requirements. It can be directly installed near the chassis drive axle or wheel-side reduction drive. The driving motor switch 14 is a high-current AC contactor located in the three-phase AC circuit between the inverter 6 and the driving motor 15, responsible for controlling the power supply to the driving motor 15. The driving motor Hall angle sensor 16 is installed at the rotor shaft end of the driving motor 15, used to detect the rotor's position and speed signals in real time. It has high detection accuracy and fast response speed, providing basic data for vector control. The current detector 19 is a Hall-type current sensor connected in series in the drive circuit between the inverter 6 output and the driving motor switch 14, used to detect the three-phase operating current of the driving motor 15, realizing overcurrent protection and current feedback control.

[0042] The power supply unit includes a working motor switch 17 and a working power supply interface. The working motor switch 17 is an AC contactor, whose input terminal is connected in parallel to the output terminal of the generator body 2 via a cable. The output terminal forms the working power supply interface, which can be designed as a single-phase or three-phase interface according to the power requirements of the upper-mounted working equipment, and is compatible with working motors 18 of different voltage levels such as 220V and 380V. The working motor 18 can be a permanent magnet synchronous motor or an asynchronous induction motor, and the specific selection or power supply is based on the power requirements and speed characteristics of the upper-mounted equipment.

[0043] The system controller, with its core being the central controller 10, employs a high-performance microprocessor as its control core. It integrates functional modules such as the engine speed controller 12, engine cruise control controller 13, and inverter circuit driver 11, possessing multi-channel signal acquisition, high-speed data processing, and precise control output capabilities. The central controller 10 is connected via hardwired connections or a communication bus (such as a CAN bus) to the generator speed sensor 9, the travel motor Hall angle sensor 16, the current detector 19, the travel motor switch 14, the work motor switch 17, and the electronic throttle 7 and cruise control switch 8 of the driver's operating unit. Simultaneously, it establishes communication with the electronic control unit of the engine body 1 via the CAN bus to transmit speed commands and provide feedback on engine operating status. The generator speed sensor 9 is installed at the non-power output end of the generator body 2 to detect the generator speed signal in real time and feed it back to the central controller 10, providing a basis for closed-loop speed control.

[0044] The working principle is as follows:

[0045] The system implements two operating modes through the central controller 10:

[0046] First operating mode (driving mode):

[0047] The driver operates the electronic throttle 7. The central controller 10 analyzes the throttle opening signal of the electronic throttle 7. The engine speed controller 12 inside the central controller 10 calculates the target speed based on this signal and sends it to the ECU of the engine body 1 via the communication bus, thereby controlling the engine body 1 to change gears. The generator body 2, which is directly connected to the engine body 1, changes gears synchronously, and the frequency and voltage of its output AC power change synchronously with the speed.

[0048] The alternating current is stepped down by the high-frequency transformer 3, rectified and filtered by the rectifier 4 and the filter capacitor 5, resulting in a reduced DC bus voltage. Simultaneously, the central controller 10 receives commands from the electronic throttle 7, rotor position signals from the Hall effect angle sensor 16 of the travel motor, and motor phase currents detected by the current detector 19. The inverter circuit driver 11 inside the central controller 10 performs vector control calculations based on these signals, generating PWM signals to drive the inverter 6. The inverter 6 converts the DC power into three-phase alternating current with controllable frequency and voltage, driving the travel drive motor 15 and continuously variable transmission (CVT) of the vehicle via the mechanical transmission system. By controlling the engine speed 1 via the electronic throttle 7, stepless speed regulation of the travel drive motor 15 can be achieved, thereby controlling the continuously variable transmission of the mobile chassis.

[0049] Second working mode (operation mode):

[0050] When the vehicle arrives at the work site and the superstructure equipment is needed, the driver raises the engine body 1 to the preset rated speed (for example, the speed corresponding to the 50Hz power frequency output of the generator body 2) through the electronic throttle 7, and then closes the cruise control switch 8.

[0051] After receiving the signal from the cruise control switch 8, the central controller 10 activates the internal engine cruise control controller 13. The engine cruise control controller 13 takes over the speed control, precisely locking the engine speed of the main unit 1 at the rated value. At this time, the generator 2 operates stably, outputting three-phase AC power with a fixed frequency (e.g., 50Hz) and a fixed voltage (e.g., 380V).

[0052] The central controller 10 controls the travel motor switch 14 to open and simultaneously controls the work motor switch 17 to close. Stable AC power at the industrial frequency is directly supplied to the work motor 18 through the work power supply unit, driving the work equipment on its upper structure. In this mode, the engine body 1 operates at its efficient and stable rated operating point.

[0053] The two modes can be switched through driver operation or automatic program judgment, achieving efficient and optimized adaptation of a single power source to two completely different working conditions: walking and working.

[0054] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An environmentally friendly single-power electric drive system for engineering mobile machinery, characterized in that, include: The variable frequency generator set consists of a direct connection between the engine body (1) and the generator body (2); The power conversion unit has its input end connected to the output end of the generator body (2); The walking drive unit includes a walking drive motor (15), the power input terminal of which is connected to the output terminal of the power conversion unit; A power supply unit for connecting the working motor (18); The system controller is connected to the engine body (1), generator body (2), power conversion unit and driver operation unit respectively; The system controller is configured to have at least two operating modes: In the first working mode, the engine body (1) and generator body (2) are controlled by electronic throttle to run synchronously at different speeds, and the walking drive motor (15) is driven by AC power output through the power conversion unit with variable frequency and voltage. In the second working mode, the cruise control switch (8) is used to control the engine body (1) and generator body (2) to run stably at the rated speed, so that the generator body (2) outputs AC power with a fixed frequency and voltage, and supplies power to the working motor (18) through the working power supply unit.

2. The environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 1, characterized in that, The system controller includes a central controller (10), an inverter circuit driver (11), an engine speed controller (12), and an engine cruise control controller (13). The driver operating unit includes an electronic throttle (7) and a cruise control switch (8). In the first working mode, the engine speed controller (12) adjusts the engine speed according to the signal of the electronic throttle (7); in the second working mode, the engine cruise control controller (13) locks the engine speed according to the signal of the cruise control switch (8).

3. The environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 2, characterized in that, The power conversion unit includes a high-frequency transformer (3), a rectifier (4), a filter capacitor (5), and an inverter (6) connected in sequence; the input end of the high-frequency transformer (3) is connected to the generator body (2), and the output end of the inverter (6) is connected to the walking drive motor (15) through the walking motor switch (14).

4. The environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 3, characterized in that, It also includes a current detector (19), which is set in the drive circuit between the inverter (6) and the walking drive motor (15); the walking drive motor (15) is provided with a walking motor Hall angle sensor (16). The central controller (10) is connected to the electronic throttle (7), the Hall angle sensor (16) of the walking motor and the current detector (19) for performing vector calculations based on the received signals and controlling the inverter (6) through the inverter circuit driver (11).

5. The environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 1, characterized in that, The generator body (2) is also connected to a generator speed sensor (9) at its output end, which is used to feed back the speed signal to the engine cruise control controller.

6. The environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 1, characterized in that, The working power supply unit includes a working motor switch (17) connected to the output end of the generator body (2), and the output end of the working motor switch (17) constitutes the working power supply interface.

7. The environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 1, characterized in that, The generator body (2) is a high-speed permanent magnet synchronous generator.

8. An environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 7, characterized in that, The walking drive motor (15) is a permanent magnet synchronous motor.

9. An environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 1, characterized in that, The engine body (1) is an internal combustion engine or gas fuel engine that meets China VI or higher emission standards.

10. An environmentally friendly single-power electric drive system for engineering mobile machinery according to claim 4, characterized in that, The working power supply unit includes a working motor switch (17) connected to the output end of the generator body (2). The central controller (10) is connected to the generator speed sensor (9), the work motor switch (17) and the cruise control switch (8) respectively. In the second working mode, it controls the engine speed to reach the rated value according to the feedback of the generator speed sensor (9) and controls the work motor switch (17) to close.

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