Series-parallel electromechanical composite transmission system bench test platform

Abstract

The invention, which relates to the technical field of the hybrid electric vehicle, discloses a series-parallel electromechanical composite transmission system bench test platform comprising a coupling mechanism, a power source, a dynamometer and a control system. The power source comprises an engine, a first permanent magnet synchronous motor and a second permanent magnet synchronous motor; the power source and the dynamometer are both connected with the coupling mechanism, and torque of the power source drives the dynamometer together through the coupling mechanism; the power source is further connected with the control system, and the control system is used for calculating driving torque and vibration compensation torque according to instructions of the controller and sensing information collected by the rotating speed torque sensor and driving the power source to operate according to the driving torque and the vibration compensation torque. The method can verify the control effects of various control strategies, and has a good use value.

Description

Technical Field

[0001] The invention relates to the technical field of hybrid electric vehicles, and in particular to a bench test platform for a series-parallel electromechanical composite transmission system. Background Art

[0002] Electromechanical composite technology can significantly improve vehicle fuel economy, power and emissions, and has attracted the attention, research and development, and promotion and application of many scholars, research institutions, and vehicle manufacturers in various disciplines at home and abroad. The growing demand for environmentally friendly hybrid systems has led to the development of advanced energy management and coordinated control algorithms to maximize fuel economy and reduce pollutant emissions. Through the study of many energy management strategies based on optimization algorithms, it is found that due to the high computational complexity, they can only be in the theoretical research stage and are difficult to use for real-time control. At the same time, current research on electromechanical composites is more focused on structural design matching, energy management, and power coordinated control. With the increasing maturity of electromechanical composite technology, the quality of vehicle driving has also received increasing attention. While people are pursuing the improvement of power and economy, their requirements for ride comfort are also gradually increasing, and research on transmission system vibration control has become increasingly important. At present, the torsional vibration of the transmission system has become one of the important factors hindering the development of high-speed, precision, and lightweight vehicles. Controlling the torsional vibration of the transmission system is an issue that must be faced and urgently needs to be solved in the design of electromechanical composite transmission systems.

[0003] At present, there are many theoretical achievements in hybrid power, power coordination, and active vibration control. However, due to the complexity of the targeted systems and the high real-time requirements of the control algorithms, there are many difficulties in algorithm verification, which affects the engineering application potential of mechatronic control algorithms. Summary of the invention

[0004] The purpose of the present invention is to provide a parallel-parallel electromechanical composite transmission system bench test platform for verifying the control effects of various control strategies, which has good use value.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A parallel-parallel electromechanical composite transmission system bench test platform, comprising: a coupling mechanism, a power source, a dynamometer and a control system; the power source comprises an engine, a first permanent magnet synchronous motor and a second permanent magnet synchronous motor;

[0007] The power source and the dynamometer are both connected to the coupling mechanism, and the torque of the power source drives the dynamometer together through the coupling mechanism;

[0008] The power source is also connected to the control system, which is used to calculate the driving torque and the vibration compensation torque according to the controller instructions and the sensor information collected by the speed torque sensor, and drive the power source to operate according to the driving torque and the vibration compensation torque.

[0009] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0010] The parallel-parallel electromechanical transmission system bench test platform provided by the present invention includes three power sources, namely an engine and two motors. The engine and the motor are controlled by corresponding engine controllers and motor controllers, and the entire test platform is controlled by the vehicle controller. The test platform can be used to verify multiple electromechanical transmission multi-power source control strategies and has very good practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0012] Figure 1 A schematic diagram of the structure of a bench test platform for a series-parallel electromechanical composite transmission system provided by the present invention;

[0013] Figure 2 It is a schematic diagram of the vehicle speed following curve;

[0014] Figure 3 It is a schematic diagram of the engine speed curve;

[0015] Figure 4 Schematic diagram of the speed curve of motor A (i.e., the first permanent magnet synchronous motor);

[0016] Figure 5 Schematic diagram of the speed curve of motor B (i.e., the second permanent magnet synchronous motor);

[0017] Figure 6 It is a schematic diagram of the output torque curve of the coupling mechanism;

[0018] Figure 7 It is a schematic diagram of the engine torque curve;

[0019] Figure 8 It is a schematic diagram of the torque curve of motor A;

[0020] Fig. 9 It is a schematic diagram of the torque curve of motor B;

[0021] Fig.10It is a schematic diagram of the battery SOC curve;

[0022] Fig.11 It is a schematic diagram of the distribution of engine operating points;

[0023] Fig.12 This is a schematic diagram of the distribution of working points of motor A;

[0024] Fig.13 This is a schematic diagram of the working point distribution of motor B;

[0025] Fig.14 It is a time domain schematic diagram of the output shaft torque under active control;

[0026] Fig.15 It is a time domain schematic diagram of the output shaft torque without active control;

[0027] Fig.16 It is a frequency domain diagram of the output shaft torque under active control;

[0028] Fig.17 It is a frequency domain diagram of the output shaft torque without active control. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The purpose of the present invention is to provide a parallel-parallel electromechanical composite transmission system bench test platform for verifying the control effects of various control strategies.

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 1 As shown, the bench test platform for the hybrid electromechanical transmission system provided by the present invention is characterized by comprising: a coupling mechanism, a power source, a dynamometer and a control system.

[0033] The power source includes an engine, a first permanent magnet synchronous motor (ie, motor A) and a second permanent magnet synchronous motor (ie, motor B).

[0034] The control system includes: a vehicle controller and an engine controller connected to the vehicle controller, a first motor controller (ie, motor A controller), a second motor controller (ie, motor B controller) and a dynamometer controller.

[0035] The power source and the dynamometer are both connected to the coupling mechanism, and the torque of the power source drives the dynamometer through the coupling mechanism. The dynamometer acts as the load of the system, simulates the driving resistance, and applies the resistance torque to the system.

[0036] The power source is also connected to a control system, which is used to calculate the driving torque and the vibration compensation torque according to the controller instructions and the sensor information collected by the speed torque sensor, and drive the power source to operate according to the driving torque and the vibration compensation torque.

[0037] Wherein, the engine controller is used to drive the engine to operate according to the control instruction.

[0038] The first motor controller is used to calculate the driving torque and vibration compensation torque of the first permanent magnet synchronous motor according to the control instruction and the sensing information collected by the speed torque sensor, and drive the first permanent magnet synchronous motor to operate according to the driving torque and vibration compensation torque of the first permanent magnet synchronous motor.

[0039] The second motor controller is used to calculate the driving torque and vibration compensation torque of the second permanent magnet synchronous motor according to the control instruction and the sensing information collected by the speed torque sensor, and drive the second permanent magnet synchronous motor to operate according to the driving torque and vibration compensation torque of the second permanent magnet synchronous motor.

[0040] The dynamometer controller is used to drive the dynamometer to operate according to the control instruction.

[0041] Specifically, the engine controller, the motor controller and the dynamometer controller are all connected to the vehicle controller through the CAN bus. The engine, the motor and the dynamometer are all connected to the coupling mechanism with a speed torque sensor to record the change of the torque on the transmission shaft. At the same time, the torque signal of the speed torque sensor is also transmitted to the motor controller through the signal conversion chip as the feedback signal of the active vibration control. The active vibration control algorithm is integrated in the motor controller. According to the feedback signal of the speed torque sensor and the control instruction sent by the vehicle controller, the vibration compensation torque is calculated in the motor controller. The motor controller drives the motor to run according to the control instruction of the vehicle controller, so that the motor first generates the driving torque. At the same time, the active vibration control algorithm is integrated in the motor controller, receives the signal of the speed torque sensor, calculates the vibration compensation torque in the motor controller according to the feedback signal, and drives the motor to generate the vibration compensation torque. The vibration compensation torque is added to the driving torque to form the final motor torque and drive the motor to run.

[0042] The above-mentioned parallel-parallel electromechanical composite transmission system bench test platform also includes: a power battery pack connected to the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

[0043] The working principle of the parallel-parallel electromechanical transmission system test bench is as follows: the host computer applies instructions to the vehicle controller (RapidECU) through USBCAN. The vehicle controller then sends the control instructions to the engine controller and the motor controller through the CAN line, and these underlying controllers drive the power source to operate. At the same time, the underlying sensors also feedback the test bench operation status information to form a closed-loop control. The sensor signals are recorded and stored through the LMS data acquisition system. The key components in the parallel-parallel electromechanical transmission system test bench will be introduced below.

[0044] 1) Engine

[0045] In this embodiment, the engine adopts a turbocharged diesel engine, which is the main power source and the main excitation source causing the system vibration. The main performance parameters of the engine are shown in Table 1.

[0046] Table 1 Basic performance parameters of diesel engine

[0047] project Numeric unit Rated Power 120 kW Rated speed 2300 r / min Maximum Torque 700 N·m Maximum torque speed 1650 r / min Number of cylinders 4 - Stroke number 4 - stroke 130 mm Displacement 4.76 L Cylinder diameter 108 mm

[0048] 2) Power battery pack

[0049] Samsung INR21700-50E battery cells are used in this embodiment, and the nominal voltage of the single battery cell is 3.63V. 96 single battery cells (6 series and 16 parallel) form a module, and the finished battery consists of 16 modules. A battery box contains 8 modules, and the entire power battery pack consists of two battery boxes and a high-voltage control box. The nominal voltage of the overall power battery pack is 345.6V, and the battery capacity is 80Ah. The battery pack parameters are shown in Table 2.

[0050] Table 2 Battery pack design parameters

[0051] project parameter Cell Type Samsung INR21700-50E Grouping method 96S16P Group nominal voltage 345.6V Group nominal capacity 80Ah Rated discharge current 80A Maximum discharge current 160A / 60S Charging Current 20A Total system energy 27.648 kWh Operating temperature -20～60(℃)

[0052] 3) Permanent magnet synchronous motor and controller

[0053] The two motors in the bench test platform are four-quadrant permanent magnet synchronous motors with the same power and model, with a rated power of 60kW and a reference speed of 2600r / min. The basic parameters of the motors are shown in Table 3.

[0054] Table 3 Basic parameters of motor

[0055] project Numeric unit Rated Power 60 kW Peak Power 110 kW Peak torque 400 N·m Reference speed 2600 r / min Maximum speed 5500 r / min

[0056] The motor controller is a D-type motor controller produced by Beijing Qi'an Electric Technology Co., Ltd. The basic parameters of the motor controller are shown in Table 4. The motor controller contains an ARM chip and a DSP chip, wherein the ARM chip is mainly responsible for the external function development of the controller, including simulation, digital signal acquisition and processing, CAN communication, 485 communication processing, etc., and the DSP is mainly responsible for motor drive control. In this embodiment, in order to ensure that the active vibration control can respond quickly, the algorithm of active vibration control is integrated into the ARM chip of the motor controller. The control program is developed using the software KeiluVision4, and the vibration control program is added between the received CAN torque command and the command sent to the DSP chip using C language. The code program is compiled and burned into the ARM chip through the ULINK2 emulator.

[0057] Table 4 Basic parameters of D-type motor controller

[0058] project Numeric unit Rated Power 100 kW Peak Power 250 kW Rated output current AC 210 A Short-time working current AC 520 A Controller efficiency at rated conditions ≥98％ -

[0059] 4) Coupling mechanism

[0060] The coupling mechanism used in this embodiment retains its power splitting and continuous transmission ratio characteristics. The switching of different gears is achieved by changing the output position, thereby omitting the gear shift clutch device.

[0061] 5) Dynamometer

[0062] In this embodiment, a CW440 eddy current dynamometer produced by Luoyang Nanfeng Electromechanical Equipment Co., Ltd. is used to apply load to the system. The maximum power is 440kW, the maximum current is 23A, and the maximum speed is 6500r / min. The dynamometer can achieve constant speed control or constant torque control, and the speed and torque values ​​are displayed in real time. The loading torque can be adjusted by the knob on the console, and the speed or torque of the dynamometer can also be controlled by an external control box.

[0063] The test verification results and analysis of the bench test platform for the hybrid electromechanical transmission system provided by the present invention are as follows:

[0064] 1) Energy management strategy test

[0065] The present invention verifies the energy management strategy in EVT2 mode. Under specific cycle conditions, the simulation results and experimental results of the energy management strategy are compared and analyzed, and the fuel economy experiment is shown in Table 5, where the "target" value represents the simulation result and the "actual" value represents the experimental result. Due to the gap between the simulation model accuracy of each component of the dual-mode hybrid electromechanical transmission and the actual engine and motor system characteristics in the test bench, the actual value and target value of the fuel economy of the dual-mode hybrid electromechanical transmission vehicle are ultimately different.

[0066] Table 5 Fuel economy test results

[0067]

[0068] The characteristic curves of each component of the dual-mode hybrid electromechanical transmission are as follows: Figure 2-Figure 17 shown. Figure 2 is the vehicle speed following curve, and the speed is calculated from the speed at the output end of the coupling mechanism. Figure 2 It can be seen that the actual vehicle speed can track the target vehicle speed well. Figure 3 , Figure 4 and Figure 5 are the engine speed, motor A speed and motor B speed respectively, and Figure 3-Figure 5 It can be seen that the curve change trends of the actual value and the target value are exactly the same. This is also due to the difference between the accuracy of the simulation model and the engine and motor characteristics in the bench test platform. In addition, during the implementation of the control strategy, the same control instructions are transmitted differently in the simulation and bench test platform processes. In the simulation process, control instructions can be transmitted accurately, while the bench test platform transmits instructions through CAN communication based on network-oriented control, which results in packet loss, delay, and numerical conversion, resulting in differences between the actual value and the target value.

[0069] Figure 6-Figure 9 are the coupling mechanism output torque, engine torque, motor A torque and motor B torque respectively, and are Figure 6-Figure 9 It can be seen that the actual output torque characteristics of the coupling mechanism are basically the same as the target torque characteristics, which fully meets the system power requirements. The control strategy leads to a more stable engine torque and a larger torque variation range of motor A and motor B, which is conducive to adjusting the engine operating point and improving fuel economy. Fig.10 is the battery SOC curve, Fig.10 It can be seen that both the target value and the actual value can maintain the SOC balance well. Figure 11-13 These are the operating point distribution diagrams of the engine, motor A, and motor B. Most of the engine and motor operating points are distributed in the high efficiency range, which is conducive to improving fuel economy. The target value is very close to the actual value, which verifies the effectiveness of the energy management strategy.

[0070] 2) Active vibration control algorithm test

[0071] In the bench test platform of the hybrid electromechanical transmission system, only active control tests were carried out on the steady-state operating conditions of the system. An adaptive filter is constructed to identify the transmission system model of the secondary path offline, so as to improve the control effect as much as possible under the premise of ensuring stable control. The test work demonstrated by the present invention is in EVT2 mode. The output mean torque of the system is stable at 300N·m, and the control effect of active vibration control is tested when the vibration source engine of the system works at 1200r / min and 1400r / min. The average torque of motors A and B is determined by the vehicle control strategy. The active vibration control algorithm runs in the motor controller, and the active suppression of the transmission shaft torque is achieved by controlling the torque of motors A and B.

[0072] The torque comparison of the output shaft with and without active control is shown in Figure 14-15 As shown. It can be seen that at different speeds, the active control algorithm can achieve a significant reduction in the torque fluctuation amplitude. Due to the large number of unstable factors in the actual bench test platform, the control effect fluctuates slightly, but it still has a significant vibration suppression effect. The comparison of the mean square error of the torque on the drive shaft with and without active control is shown in Table 6.

[0073] Table 6 Comparison of mean square difference of output shaft torque before and after active control

[0074]

[0075] The torque frequency domain comparison of the output shaft with and without active control is shown in Figure 16-Figure 17 As shown in the figure, it can be seen that when the engine speed is 1200r / min, the vibration components on the transmission shaft are mainly 1 times (20Hz) and 2 times (40Hz) of the engine speed. When the engine speed is 1200r / min, the vibration components on the transmission shaft are mainly 23Hz and 47Hz, which are also 1 times and 2 times of the engine speed respectively. It can be seen that it is reasonable to take the multiple of the engine speed as the active control object. Figure 16-Figure 17 It can be seen that after applying active control, the amplitudes of the 1st and 2nd frequency components of the engine speed on the transmission shaft have decreased significantly, verifying the effectiveness of active control in the bench test platform of the hybrid electromechanical transmission system.

[0076] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0077] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A parallel-parallel electromechanical transmission system bench test platform, characterized in that: include: A coupling mechanism, a power source, a dynamometer and a control system; the power source includes an engine, a first permanent magnet synchronous motor and a second permanent magnet synchronous motor; The power source and the dynamometer are both connected to the coupling mechanism, and the torque of the power source drives the dynamometer together through the coupling mechanism; The power source is also connected to the control system, which is used to calculate the driving torque and the vibration compensation torque according to the controller instructions and the sensor information collected by the speed torque sensor, and drive the power source to operate according to the driving torque and the vibration compensation torque.

2. The bench test platform for the series-parallel electromechanical transmission system according to claim 1 is characterized in that: Also includes: A power battery pack connected to the first permanent magnet synchronous motor and the second permanent magnet synchronous motor.

3. The bench test platform for the series-parallel electromechanical transmission system according to claim 1 is characterized in that: A speed torque sensor is connected between the power source and the coupling mechanism, and between the dynamometer and the coupling mechanism. The speed torque sensor is used to record the current torque of the power source and the dynamometer.

4. The bench test platform for the series-parallel electromechanical transmission system according to claim 3 is characterized in that: The control system comprises: a vehicle controller and an engine controller, a first motor controller, a second motor controller and a dynamometer controller connected to the vehicle controller; The vehicle controller is used to send control instructions to the engine controller, the first motor controller, the second motor controller and the dynamometer controller; The engine controller is used to drive the engine to operate according to the control instruction; The first motor controller is used to calculate the driving torque and vibration compensation torque of the first permanent magnet synchronous motor according to the control instruction and the sensing information collected by the speed torque sensor, and drive the first permanent magnet synchronous motor to operate according to the driving torque and vibration compensation torque of the first permanent magnet synchronous motor; The second motor controller is used to calculate the driving torque and vibration compensation torque of the second permanent magnet synchronous motor according to the control instruction and the sensing information collected by the speed torque sensor, and drive the second permanent magnet synchronous motor to operate according to the driving torque and vibration compensation torque of the second permanent magnet synchronous motor; The dynamometer controller is used to drive the dynamometer to operate according to the control instruction.

5. The bench test platform for the series-parallel electromechanical transmission system according to claim 4 is characterized in that: The engine controller, the first motor controller, the second motor controller and the dynamometer controller are connected to the vehicle controller via a CAN bus.

6. The bench test platform for the series-parallel electromechanical transmission system according to claim 1 is characterized in that: The first permanent magnet synchronous motor and the second permanent magnet synchronous motor are four-quadrant permanent magnet synchronous motors with the same power and model, with a rated power of 60 kW and a reference speed of 2600 r / min.

7. The parallel-parallel electromechanical transmission system bench test platform according to claim 1 is characterized in that: The dynamometer is a CW440 eddy current dynamometer with a maximum power of 440 kW, a maximum current of 23 A, and a maximum speed of 6500 r / min.

Images