Development Of Intelligent DC Electronic Load

When the power performance testing usually requires access to the different nature and the resistance of the load, the traditional testing methods have significant limitations. DC electronic load with traditional analog resistive load, compared with low energy consumption, small size, easy to carry, high precision, easy to operate, the power supply, automotive, batteries and other fields has been widely used, and has become a research hot spots. Electronic load from the core controller, current and voltage detection circuit, heat sink temperature sensing circuit, E2 PROM memory circuit, USB interface circuit, USB interface circuit, the fan drive circuit, system protection circuits and other components, the core controller controls the MOSFET amount(duty size) to achieve stable control of circuit parameters.Firstly, the overall design of DC electronic loads were related to the introduction, by comparing several solutions, has been the system design ideas. The design selected from the analysis of DC electronic load system program, a detailed discussion of the hardware circuit and software design ideas throughout the DC electronic load on the system, and gives reasonable final solution. In order to facilitate the realization of extended control and related functions, using MSP430F149 as the core controller, the control circuit design, voltage, current detection circuit, keyboard circuit, LCD12864 display circuit, heat sink temperature detection circuit. By incremental PID control technology and coordination of software and hardware to achieve the overall design of DC electronic loads. MSP430F149 microcontroller PWM output duty cycle of different waveforms, control is turned off and the time of the MOS transistor, by adjusting the flow of current through the FET voltage and power at both ends of the subjects, to achieve constant current, constant power, constant resistance of four operating modes.Test results show that through hardware and software, electronic load of this design can be achieved manually constant within the range of 300 W, constant voltage, constant power and constant resistance switching and four operating modes with high accuracy.