Design Of A Distributed Control System For Battery Charge/Discharge Process

Charge/Discharge processing is one of the most important processes in storage battery production. In battery industry, the Charge/Discharge process is controlled by electrical power conversion devices with the function of rectifying and inverting.This thesis presents a scheme of distributed intelligent controlling for storage battery charging/discharging process. The control system regulates the voltage or current automatically in the charge or discharge of battery groups according to technologic requirements.The control system consists of a personal computer, power converters and controllers, converters, and communication networks. The personal computer takes advantage of using advanced programming tools to manage database and distributed control tasks to the converter controller units by means of data communication. The personal computer is also responsible for process parameters monitoring and system fault diagnosing. The power converter controller units control the charge or discharge current and voltage in real-time, and switch the converters between rectifier and inverter operating modes in keeping with the charge/discharge commands sent from the high level personal computer. The power converters are Pulse-Width Modulation (PWM) rectifiers which include switching devices to achieve high power conversion from AC to DC and vice versa. Communication network is used for data transferring to realize the centralized management and distributed control.Computer information processing software designed in Visual C++ in Personal computer is used to monitor all microcontrollers in the network. It has a friendly interactive interface and abundant functions, and it can also share the information on the wide area network and response for the operation of the network, so it can realize the true meaning of the distributed control.The power converter controller can get the process file or control parameters by local keyboard and LCD so it can operate out of the network. The real-time operating system kernelμC/OS-II is transplanted and implemented in the distributed control system. In the software design, many tasks with different priorities are designed as different functional modules, which are scheduled by the RTOS kernel. The multitasking real-time kernel promotes an orderly transfer of control from one task to another such that efficient usage of the microcontroller resources is achieved. The software design greatly improves the real-time property, reliability and maintainability of the battery charge/discharge control system.