Analysis of a measurement system in respect to the dependency of the current sensor sampling rate and the inverter switching time

Abstract

The range of the sensors, which are used for the measurement of electrical quantities recorded over a decade in an enormous growth. The sensor is established in many areas, such as in the energy technology, in drive technology or in the automotive industry. The demand as well as the request to the sensor and in particular for the current sensors have reshaped by technological progress. Accordingly the following problematic aspects are to consider, which as on the one hand, the potential-free transmission of the measured value (in the long distance) and on the other hand, the influence with relating to the sampling frequency of the measured value of current sensors in view of the switching frequency of power converters. Therefore, a new chip was developed to measure currents in power electronics. The measuring chip is located directly on a shunt resistor. The measured value will be transmitted to the power electronics driving with a new modulation method, which is called frequency pulse-width modulation (F-PWM). The aim of the method and also for the whole current sensor is the transmission of the measured value with a high resolution and accuracy. Another aspect in this paper is the influence relating to the sampling frequency of the measured value of current sensors in view of the switching frequency of power converters. It will investigate how or whether the system behavior and the system dynamics changed by influencing the frequencies. A simulated model of the developed current sensor is to be installed in a system model, which contains a power converter and the electrical grid. An analysis should show whether it is necessary to increase the sampling rate of the current sensor, when the power inverter will work with a higher sampling frequency (e.g. 64kHz) in the future.