Control system of series hybrid mining dump truckTechnical Field
The invention relates to a dump truck, in particular to a control system of a series hybrid mining dump truck.
Background
The hybrid mining dump truck is divided into a serial type, a parallel type and a series-parallel type, and the serial type structure is relatively simple and the application is wider. The hybrid mining dump truck mainly uses working conditions such as heavy load ascending and descending, heavy load descending and descending, no load ascending and descending, straight road running and the like, mining area roads are relatively simple and single, and vehicles are repeatedly loaded, transported and unloaded on the relatively single roads.
The mining dump truck has the characteristics of severe load change, strong periodicity and the like. The most critical factor for saving oil consumption of the series hybrid mining dump truck is the control of the power generation of the range extender. The power generation power of the range extender is basically determined through the angle of an accelerator pedal and the SOC of a battery, so that the control is relatively simple, and the range extender is not controlled by combining the required power and the transportation working condition of the mining dump truck.
The existing hybrid dump truck has the control defects that:
1. The power requirement of the vehicle cannot be directly reflected by the accelerator pedal, if the power generation power of the range extender is determined by the angle of the accelerator pedal and the SOC of the battery, the range extender has the problem that the power speed regulation is frequently regulated, and the fuel economy of the whole vehicle is poor.
2. In the running process, the stop time of the range extender is not good, so that the range extender is frequently started or idling time is long, and fuel economy is poor.
3. Under the heavy-load downhill working condition, the whole vehicle has smaller electric braking power due to the limitation of battery feedback power, mechanical braking supplement is needed, the loss of mechanical braking parts is larger, and potential safety hazards exist.
Disclosure of Invention
The invention aims to solve the technical problem of providing a control system of a series hybrid mining dump truck, which improves the fuel economy of the hybrid mining dump truck and the safety of heavy load downhill of the vehicle.
In order to solve the technical problems, the technical scheme of the invention is as follows: a control system of a series hybrid mining dump truck,
The hybrid system includes:
The range extender and the control unit RCU thereof, wherein the range extender is a combination of an engine and a generator; the range extender generates power according to the power requirement given by the VCU of the whole vehicle controller, provides electric energy for the electric load on the vehicle and charges the power battery; when the whole vehicle is electrically braked, the electric power output by the driving motor exceeds the charging power of the power battery or the battery is full, the generator is used as a motor, and the electric energy is consumed in an engine cylinder braking mode;
the generator controller and the control unit MCU1 thereof rectify alternating current generated by the range extender into direct current, the voltage is matched with the voltage of the power battery, and the generator controller is used as an inverter when the engine cylinder brakes;
The driving motor controller and the control unit MCU2 thereof are used for inverting the direct current into alternating current with adjustable voltage frequency under the traction state, and rectifying the alternating current generated by the driving motor into direct current under the electric braking state;
The power battery provides electric energy for the whole vehicle when the power of the range extender is insufficient, absorbs the electric energy when the power of the range extender is larger than the load power, and absorbs the electric energy generated by the driving motor when the whole vehicle is electrically braked;
the driving motor is internally provided with a gradient sensor, and when in a traction state, the suspension cylinder sensor detects the pressure value of the suspension cylinder sensor to judge the load condition of the whole vehicle, and the gradient sensor detects the gradient of a running line of the vehicle;
the whole vehicle controller VCU controls the power generation of the range extender according to signals of an accelerator pedal, a brake pedal, a battery SOC, a suspension cylinder sensor and a gradient sensor;
Hybrid powertrain control strategy:
The working condition is defined as W1 when the power generation power is 200kW, the working condition is defined as W2 when the power generation power is 300kW, the working condition is defined as W3 when the power generation power is 400kW, and the working condition is defined as W0 when the range extender is idling or stopped and does not generate power;
Under the traction working condition, when the SOC value of the power battery is lower and the power demand is larger, a W3 working condition is adopted, when the SOC value of the power battery is higher and the power demand is smaller, a W1 working condition is adopted, when the power demand of the driving motor is very small and the SOC value of the power battery is higher or the driving motor is in a power generation state, the range extender is idling or stopped, namely, the range extender works under a W0 working condition;
Under the working condition W0, determining whether the range extender runs at idle speed or stops according to the battery SOC value and whether the whole vehicle is in a downhill electric braking state;
under the electric braking working condition, the driving motor is in a power generation state, whether the whole vehicle is in a heavy-load downhill working condition or not is detected through the suspension cylinder sensor and the gradient sensor, when the whole vehicle is in the heavy-load downhill working condition and meets the setting condition, the braking in the power amplifier Cheng Qigang is automatically started, the power generated by the driving motor is supplied to the power battery for supplementing electricity, and the power is consumed in a mode of braking in the power amplifier Cheng Qigang beyond the part of the power battery for absorbing power.
The principle of the invention is as follows: the time of the engine working in the high-efficiency area is as much as possible, and the engine is not frequently regulated and started and stopped as much as possible under the condition that the requirements of vehicle traction and braking are met, and the unit oil consumption is increased due to frequent starting and stopping of the engine and speed regulation; according to the invention, through a control strategy, the frequent speed regulation of the range extender is reduced, and the fuel economy of the hybrid mining dump truck is improved. The electric braking power of the whole vehicle is improved when the heavy load descends, the dependence on mechanical braking is reduced, the loss of mechanical braking parts is reduced, and the safety of the heavy load of the vehicle descends is improved.
As improvement, the power battery SOC value is 0-30% and the load power is 300-600 kW, the power battery SOC value is 30-80% and the load power is 400-600 kW, and the power battery is positioned as a W3 working condition; the power battery SOC value is 0-30% and the load power is 0-300 kW, and the power battery SOC value is 30-50% and the load power is 200-400 kW, so that the working condition is positioned as W2; the power battery SOC value is 50-80% and the load power is 200-400 kW, and the power battery SOC value is 80-100% and the load power is 300-600 kW, so that the working condition is positioned as W1; the power battery SOC value is 30-100% and the load power is 0-200 kW, and the power battery SOC value is 80-100% and the load power is 200-300 kW, so that the working condition of W0 is located.
As an improvement, aiming at the situation that the load power requirement of the whole vehicle is changed frequently, the power increase of the range extender is sequentially increased or decreased according to the working conditions of W0, W1, W2 and W3; when the working conditions of the vehicle are switched, the conditions are required to be met for more than 10 seconds, and the power demand change of the whole vehicle within 10 seconds is realized through the power battery.
As an improvement, buffer areas are arranged between W0 and W1, between W0 and W2, between W1 and W2 and between W1 and W3, and the buffer areas are arranged in the range of 30-80% of the SOC value of the power battery.
As an improvement, the buffer area between W0 and W2 is 30-35% of the SOC value of the power battery and the load power is 0-200 kW; the buffer area between the W0 and the W1 is that the SOC value of the power battery is 75-80% and the load power is 200-300 kW; the buffer area between the W1 and the W2 is that the SOC value of the power battery is 47.5-52.5% and the load power is 200-400 kW; the buffer area between W1 and W3 is that the SOC value of the power battery is 75-80% and the load power is 400-600 kW.
Compared with the prior art, the invention has the beneficial effects that:
1. The output of the range extender is divided into four working conditions W0, W1, W2 and W3 to be controlled, the power generation power of the range extender is dynamically regulated according to the load power requirement and the SOC of the power battery, meanwhile, in order to avoid the problem that the power generation power is frequently regulated by the range extender, the energy consumption is wasted due to frequent speed regulation of an engine, time condition limitation is set, the working conditions are regulated after the conditions are met, and the load power change requirement in a short time is borne by the power battery;
2. When the load power requirement change amount is smaller, but the load power requirement change amount is in the conditions of being between W0 and W1, between W0 and W2, between W1 and W2 and between W1 and W3 for a long time, a working condition buffer zone is arranged, so that the condition of the range extender is prevented from being frequently adjusted due to the change of the SOC of the power battery;
3. The range extender is in the WO working condition, whether the range extender is stopped or not is determined according to the SOC state of the power battery and the working condition state of the whole vehicle, and energy loss caused by idle speed non-power generation in Cheng Qichang time is avoided;
4. the whole vehicle is in an electric braking state, whether the whole vehicle belongs to a heavy-load downhill state or not is judged through the suspension cylinder sensor and the gradient sensor, and whether the engine cylinder braking is started or not is judged according to the electric braking power of the whole vehicle, so that the use and loss of a mechanical braking system are reduced, and the whole vehicle is safer to operate.
Drawings
FIG. 1 is a schematic diagram of a hybrid powertrain.
FIG. 2 is a range extender operating mode demarcation diagram.
Fig. 3 is a high power charge and discharge region of the power battery.
Fig. 4 is a control flow chart in a traction state.
FIG. 5 is a control flow diagram for the W0 operating mode.
Fig. 6 is a control flow chart in the electric brake state.
Detailed Description
The invention is further described below with reference to the drawings.
As shown in fig. 1, a control system of a series hybrid mining dump truck, the whole hybrid system mainly comprises: the device comprises a range extender and a control unit RCU thereof, a generator controller and a control unit MCU1 thereof, a driving motor controller and a control unit MCU2 thereof, a power battery and control system BMS, a driving motor, a whole vehicle controller VCU, an accelerator pedal, an electric brake pedal, a suspension cylinder pressure sensor and other components.
The range extender is a combination of an engine and a generator, and has the functions of generating electricity according to the power requirement given by the VCU of the whole vehicle controller, providing electric energy for an electric load on the vehicle and charging a power battery; the other function of the range extender is that when the whole vehicle is electrically braked, the electric power output by the driving motor exceeds the charging power of the power battery or the battery is full, the generator is used as a motor, and the electric energy is consumed in an engine cylinder braking mode.
The function of the generator controller is to rectify the alternating current generated by the range extender into direct current, the voltage is matched with the voltage of the power battery, and the generator controller is used as an inverter when the engine cylinder brakes.
The driving motor controller has the function of inverting the direct current into alternating current with adjustable voltage frequency in a traction state and rectifying the alternating current generated by the driving motor into direct current in an electric braking state.
The power battery has the function of providing electric energy for the whole vehicle when the power of the range extender is insufficient, absorbing the electric energy when the power of the range extender is larger than the load power, and absorbing the electric energy generated by the driving motor when the whole vehicle is electrically braked.
The gradient sensor is arranged in the driving motor, and the pressure value of the driving motor is detected by the suspension cylinder sensor in the traction state to judge whether the whole vehicle runs in an idle or full load state; the gradient sensor is operative to detect a gradient of a running line of the vehicle.
The whole vehicle controller VCU controls the power of the generator of the range extender according to signals of an accelerator pedal, a brake pedal, a battery SOC, a suspension cylinder sensor and a gradient sensor.
Hybrid powertrain control strategy:
As shown in fig. 3, in order to develop the charge/discharge power of the power battery, the power battery SOC has as much as possible of the maximum charge/discharge power interval in the range of 30 to 80%. As shown in fig. 2, in order to achieve the energy saving objective, 3 points of the working efficient area of the engine are selected to adopt a fixed-point power generation strategy, and the fixed-point power generation strategy is defined as W1, W2 and W3 power generation working conditions according to different power levels, wherein the power generation power under the W1 working condition is 200kW, the power generation power under the W2 working condition is 300kW, the power generation power under the W3 working condition is 400kW, and the working condition of the range extender is defined as W0 when idling or stopping not to generate power.
And under the traction working condition, according to the load power demand P and the power battery SOC values, W0, W1, W2 and W3, wherein the load power P is calculated through the angle of an accelerator pedal and the vehicle speed. The power battery SOC value is 0-30% and the load power is 300-600 kW, and the power battery SOC value is 30-80% and the load power is 400-600 kW, so that the working condition is positioned as W3; the power battery SOC value is 0-30% and the load power is 0-300 kW, and the power battery SOC value is 30-50% and the load power is 200-400 kW, so that the working condition is positioned as W2; the power battery SOC value is 50-80% and the load power is 200-400 kW, and the power battery SOC value is 80-100% and the load power is 300-600 kW, so that the working condition is positioned as W1; the power battery SOC value is 30-100% and the load power is 0-200 kW, and the power battery SOC value is 80-100% and the load power is 200-300 kW, so that the working condition of W0 is located. Buffer areas are arranged between W0 and W1, between W0 and W2, between W1 and W2 and between W1 and W3, and the buffer areas are arranged in the range of 30-80% of the SOC value of the power battery; the buffer area between W0 and W2 is the power battery SOC value of 30-35% and the load power of 0-200 kW; the buffer area between the W0 and the W1 is that the SOC value of the power battery is 75-80% and the load power is 200-300 kW; the buffer area between the W1 and the W2 is that the SOC value of the power battery is 47.5-52.5% and the load power is 200-400 kW; the buffer area between W1 and W3 is that the SOC value of the power battery is 75-80% and the load power is 400-600 kW.
As shown in fig. 4, under the traction working condition, when the SOC value of the power battery is low and the power demand is high, the W3 working condition is adopted, when the SOC value of the power battery is high and the power demand is low, the W1 working condition is adopted, when the SOC value of the power battery is low and the power demand is low, the W2 working condition is adopted, and when the power demand of the driving motor is very low and the SOC value of the power battery is high or the driving motor is in the power generation state, the range extender is idling or stopped, namely, works under the W0 working condition.
As shown in fig. 5, under the W0 working condition, whether the range extender is in idle operation or stop is determined by the battery SOC value and whether the whole vehicle is in a downhill electric brake state.
In order to avoid frequent speed regulation of the engine and increase of oil consumption, the whole vehicle control strategy performs the following control: 1. when the working conditions of the vehicle are switched, the conditions are required to be met for more than 10 seconds, and the power battery can charge and discharge with short-time peak power, so that the power demand change of the whole vehicle within 10 seconds is realized through the power battery; 2. aiming at the condition that the load power of the whole vehicle is between W0 and W1, between W0 and W2, between W1 and W2 and between W1 and W3 for a long time, a working condition buffer zone is arranged, so that the range extender is prevented from frequently changing working conditions because the SOC value of the power battery jumps back and forth between working condition boundaries.
As shown in fig. 6, under the electric braking working condition, the driving motor is in a power generation state, and the suspension cylinder sensor and the gradient sensor are used for detecting whether the whole vehicle is in a heavy-load downhill working condition, when the vehicle is in the heavy-load downhill working condition and the setting condition is met, the internal braking of the motor is automatically started to increase Cheng Qigang, the power generated by the driving motor is supplied to the power battery for supplementing power, and the power is beyond the part of the power battery for absorbing power, the power can be consumed in a braking mode of the motor in the motor increase Cheng Qigang, so that the electric braking performance of the whole vehicle is improved, the input of mechanical braking when the whole vehicle is in the heavy-load downhill working condition is reduced, and the safety of the whole vehicle is improved.