I. INTRODUCTION As a result of the financial crisis, auto giants such as Europe, America and Japan have suffered heavy losses. In order to obtain rebirth, on the one hand auto companies cut through production, cut assets, sell assets, etc., and on the one hand they have spared no effort to develop new energy vehicles to offset the trend. They are subject to oil reserves and environmental protection pressures. In recent years, all countries have been vigorously developing new energy sources. car. The development of new energy vehicles has been mentioned by countries as never before.
Compared with traditional automobiles, the development of new energy vehicles in our country has also taken the lead and has not lost at the starting line. The goal of new energy vehicles proposed by Wan Gang, senior expert in the field of fuel cell vehicles in China, is: By 2012, 10% of the newly-produced cars in China are energy-saving and new energy vehicles, and the annual production of vehicles by the time will be 10 million. According to the calculation, China's new energy vehicles will reach a scale of 1 million vehicles a year. This has strengthened the determination of domestic and foreign auto makers to develop new energy vehicles in China.
Hybrid vehicles use traditional internal-combustion engines and electric motors as power sources. They use two systems of heat energy and electricity to start the car to save fuel and reduce exhaust pollution. In addition to various unit technologies such as engines, motors, and batteries, the important technologies for hybrid vehicles are the electronic control technology of each system and the power system optimization and control technology of the entire vehicle. This article focuses on the application of the WEINVIEW touch screen in the battery control system unit.
II. System Principles and Design Requirements 1: Principle of Hybrid Vehicles Hybrid vehicles adopt traditional internal combustion engines and electric motors as power sources. They use two systems of heat energy and electric power to start a car to save fuel and reduce exhaust pollution. The internal combustion engine used is both diesel engine and gasoline engine. Common features are small displacement, light weight, high speed, and good emissions. The key to the hybrid vehicle is the hybrid system. Its performance directly relates to the performance of the hybrid vehicle. The schematic diagram of the hybrid power system is shown in Figure 1.
figure 1
The hybrid system is divided into series, parallel, and mixed type. Series hybrid electric vehicles mainly consist of engines, generators, drive motors, and battery packs. The engine is only used to generate electricity. The electrical energy generated by the generator is supplied to the motor, which drives the car. Some of the electricity generated by the generator charges the battery to extend the mileage of the hybrid electric vehicle. In addition, the battery can also provide electric energy to the electric motor to drive the electric vehicle, so that the hybrid electric vehicle can run in a zero-pollution state.
figure 2
The parallel hybrid electric vehicle is mainly composed of an engine, a power generation/motor and a battery pack. The parallel drive system can use the engine or motor alone as the power source, or can use the motor and the engine as the power source to drive the vehicle. See Figure 3 for the parallel schematic.
image 3
The hybrid electric vehicle is mainly composed of an engine, a generator, a motor, a planetary gear mechanism, and a battery pack. The hybrid drive is to connect the engine, generator and motor through a planetary gear device. Power is output from the engine to the planet carrier connected to it, the planet carrier transmits a part of the torque to the generator, and the other part is transmitted to the motor and output to the drive shaft. At this time, the vehicles are not connected in series or in parallel, but they are connected in series and in parallel to take full advantage of the advantages of the two driving methods. See Figure 4 for the hybrid schematic.
Figure 4
2: Hybrid car battery control unit system setup requirements.
1: touch screen screen design requirements This system uses WEINVIEW MT8070iH model touch screen, this model is 7 "widescreen, 400MHz CPU. 128M large-capacity Flash, can quickly respond to system instructions.
The language of the screen can be switched between Chinese and English. The screen needs to have animation effects. For example, the charging and discharging process of the battery must be synchronized with the actual one and expressed by the effect of the animation.
The touch screen adopts a 7-inch widescreen, and the main screen can intuitively indicate the working condition of the user's fuel cell unit, as well as the working conditions and related parameters of each group of batteries and each battery. For this battery management unit, there are a total of 10 groups, each group has 12 batteries, the voltage, current, and temperature parameters of the 120 batteries are required to be displayed. If the parameters are out of range, an alarm must be issued. 2: Set the alarm voltage range:
When it is monitored that the voltage of any string in the battery pack exceeds 3.00—3.65V, the voltage submenu and warning triangle symbol will flash, enter the submenu of voltage, the battery pack exceeding the standard will blink, and the corresponding battery pack will be opened. Page menu, excessive string flashes.
3: Set the alarm temperature range:
When it is monitored that the temperature of any battery in the battery pack exceeds 70 degrees, the temperature submenu and warning triangle symbol will flash, enter the temperature submenu, and the excessive battery pack will flash.
4: Calculation of battery capacity:
Calculation method: total current x total voltage x time = charge and discharge power; the touch screen is required to accurately display the charge and discharge data.
III: Screen Design of Touch Screen System
1: Touch screen main monitoring screen design The main screen of the touch screen Chinese and English screen as shown below, there is a battery symbol on the entire screen, marked with the positive and negative can display the current capacity of the battery. The first dial on the screen is an ammeter, which shows the charge and discharge of the battery cells. The second meter is the voltmeter, which shows the voltage after the battery pack is inverted. Temperature and voltage controls on the screen can be displayed as alarms and can be used as function keys in the next level.
2: touch screen temperature monitoring screen design In the main screen, click on the temperature button to enter the battery module temperature monitoring screen, in this screen we can see the temperature of 10 groups of batteries. For a battery with 12 bars in each battery group, the temperature sensor measures the temperature of every 4 batteries. Therefore, there are three temperature sensors in a group of batteries. These three temperatures can be read through the touch screen. When the temperature abnormality exceeds the operating temperature of the battery, the corresponding battery icon will flash, which is convenient for the driver to view. The battery temperature monitor screen is shown below.
Battery temperature monitoring
3: touch screen temperature and voltage screen design In the main screen, click the voltage button to enter the battery module voltage monitoring screen, in the screen we can see the voltage of each cell in each group of batteries. In the quick selection bar on the left side of the screen, you can switch any other battery pack and check the detailed voltage of the battery pack.
In the battery unit, when one of the battery voltage ranges exceeds 3.00—3.65V, the corresponding battery icon will flash and carry out relevant alarm; it is convenient for the operator and the driver to inquire.
Four: The establishment of communication between the touch screen and the controller
1: Development of communication protocol For the customer's controller is developed by the microcontroller, MT8070iH and its communication must have a communication protocol to communicate with the microcontroller. The communication parameters of the SCM are already set on the SCM. For the communication parameters of the touch screen, see the following figure.
2: