Guide to selection of electronic power supply in jinshengyang-Overview

Overview:

The entire structure of an automobile is complex, with tens of thousands of parts. However, the basic structure of an automobile can be divided into four parts: Engine, chassis, body, and automotive electronics. The proportion of automotive electronics to total vehicle costs has been rising. Currently, automotive electronics accounts for 15%-30% of total vehicle costs. For some high-end vehicles, automotive electronics accounts for nearly 40%-50% of total costs. With the continuous development of intelligent technology, the development of other modules of the automobile has been fixed, and the comfort of the automobile is mainly reflected in the degree of automotive electronic intelligence. There are many on-board automotive electronic systems, it mainly includes the on-board power supply system, startup system, engine management system, lighting system and lighting management system, meter indication system, air conditioning system, auxiliary system, airbag system, automatic transmission electronic control system, electronic Control suspension system, on-board intelligent key system, on-board auxiliary system, automotive entertainment system, automotive remote communication system, automotive equipment line and on-board bus system, etc, these systems constitute an automotive electronic system.

Composition of automotive power supply:

 

The power supply system of fuel vehicles is mainly composed of battery and generator. The power supply system of dual-mode vehicles and pure electric tram is mainly composed of power battery, lead-acid battery and DC-DC voltage inverter, then, the power module or power chip is used inside each system for Voltage conversion. The main differences between the two are as follows:

 

1. the power supply system of fuel vehicles is a low-voltage system, which is generally 12 V. The power supply system of dual-mode vehicles and pure electric vehicles is both low-voltage and high-voltage, and high-voltage motors are generally 300v-500v or above, powered battery; Low Voltage 12 V, 24 V and 42 V, with lead-acid battery or DC-DC voltage inverters.

 

2. the power battery of a dual-mode vehicle or a pure electric vehicle is the power source of the vehicle. The power battery supplies power to the motor to drive the vehicle. The power of a fuel car is obtained by burning gasoline in the engine, non-electric drive.

 

Because there are multiple systems in the automobile that are often electrical equipment, in the absence of generators, lead-acid batteries are required for power supply, which is a great test for battery and electronic equipment, in particular, the power consumption of electronic devices is a core issue. Currently, many manufacturers require that the static power consumption of the vehicle's electrical equipment be less than 20mA. Therefore, for the power system, several Ma of static power consumption is required.

 

 

In more cases, the system requires a low internal voltage, which requires the voltage conversion of lead-acid batteries. Especially in the power supply of generators, the anti-interference capability of switching power supply is demanding. The AC generated by the generator is directly supplied to the system after full-wave rectification. If the power filtering measures of the entire system are improperly handled, it is easy to interfere with the system. Currently, many on-board security systems generally use isolated power supplies for conversion power supply. The cost of a non-security system is plagued by the use of a circuit built by a non-isolated chip for Voltage conversion.

 

Automotive Electronic Power Environment and requirements:

 

The application environment of the automotive power system is more complex than that of the common power system, because the electromagnetic environment in the automobile is worse. The electrical equipment of an automobile may produce a large amount of electromagnetic interference during operation. These interference frequencies are very wide and transmitted to the power supply system through transmission, coupling, or radiation, this affects the normal operation of electronic devices. The worst case is often caused by the interference of the vehicle itself, such as the interference pulse of the ignition system, generator and rectifier system.

 

The most critical reason is that all power supplies in a car are connected to a single point, so that interference between devices will directly pass through the power cord and interfere with other devices.

 

In addition to the above internal interference, compared with other common electronic products, the external environment is slightly more evil, especially temperature, humidity, vibration, rain, aging resistance, voltage fluctuation, voltage impact and other factors. More importantly, as a common Transportation Tool for humans, the reliability and security of automobiles have attracted much attention. The temperature specifications of common electronic components of automobiles are summarized as follows:

 

 

Table 1: Temperature Analysis of automotive electronic environment

Electronic internal components must also be tested by various environmental factors. Since the automotive electronics Board (AEC) has set up quality control standards, AEC-Q-100 chip stress testing specification certification for Automotive internal chip has a strict control, the AEC standard has gradually developed to the general testing specification of automotive electronic parts. After more than 10 years of efforts, AEC-Q-100 has become a general standard of automotive electronic systems. After the AEC-Q-100, The AEC-Q-101 for discrete components and passive components for the AEC-Q-200 specifications, as well as AEC-Q001, q002, q003, q004 and other guiding principles.

 

ISO 16750 series standards are the environmental reliability standards released by ISO for automotive electronics in recent years. They are common standards for European vehicles, in addition, it has gradually been transformed into a national standard by countries around the world, and has gradually been cited by various enterprise standards, becoming an Environmental Reliability Standard for automotive electronics that is widely used. The series consists of five parts:

 

Automotive Electronic electromagnetic compatibility features and requirements:

 

As there are more and more types of automotive electronic products, and many important monitoring and control system functions are replaced by electronic devices, the safe driving performance of vehicles is closely linked with the working electromagnetic environment. If the EMS capability of parts is too low, if the components are subject to internal or external electromagnetic harassment, the light may affect the product performance, or the heavy parts may directly affect the vehicle safety, resulting in personnel damage. Because vehicles and their parts have very high safety performance requirements, the vehicle's EMC standards are often more severe than the average number of electronic products.

 

The EMS test method is used to determine the anti-disturbance capability of the tested device by adding harassing energy to the tested device. For different interference energy, different test methods must be used to select a suitable coupling mode to smoothly couple the energy to the tested device. The transfer path of the added interference energy is divided into two types: radiation and conductivity. Radiation interference means that the harassing energy is transmitted from the air to the DUT (device under test) without any transmission media) or DUT line (Power Supply and signal line), and conductive interference is through the power line or signal line and other lines, the interference energy is directly coupled or injected into DUT or line. The type of disturbance energy includes two types: continuous wave and transient wave, which are divided into two coupling modes: radiation and conductivity. The anti-disturbance test method can be subdivided into four categories: continuous wave transmission, continuous wave radiation, transient conduction (transiet) and electrostatic discharge (ESD.

 

 

In response to the interference caused by automotive electronics, the international radio interference Commission (CISPR) has put forward strict requirements on the automotive electronics industry, especially the car radio, digital TV, and navigation devices. Therefore, cispr25: Limits and test methods used to protect the radio harassment characteristics of the on-board receiver. It also has a clear level decision on the launch status of Automotive Electronics. The EMS test items are as follows:

 

For electric vehicles, there are also some special requirements: In addition to meeting the requirements of the GB/T 17626 series surge and pulse group projects, there is also a special standard of GB 13837 (electric vehicle electric field and magnetic field intensity measurement methods and implementation level) specifically designed for electric vehicle self-launch.

Original Reprinted from: Guangzhou golden shengyang Technology Co., http://www.mornsun.cn/news/NewDetail.aspx? Id = 241 & channelid = 132

Guide to selection of electronic power supply in jinshengyang-Overview