Power Electronics Programmable Voltage Source with Reduced Ripple Component of Output Signal Based on Continuous-Time Sigma-Delta Modulator

In this work, an idea of a wideband, precision, power electronics programmable voltage source (PVS) is presented. One of the basic elements of the converter, the control section, contains a continuous-time sigma-delta modulator (SDM) with a pair of interconnected complementary comparators, which represents a new approach. In this case, the SDM uses comparators with a dynamic hysteresis loop (DHC) that includes an AC circuit rather than an R-R network. Dynamic hysteresis is a very effective way of eliminating parasitic oscillation during the signal transition at the input of the comparator; it also affects the frequency characteristics and, especially, the phase properties of the comparator, and this phenomenon is exploited in the proposed converter. The main disadvantage of all pulse-modulated converters is the presence of a ripple component in the output voltage (current), which reduces the quality of the output signal and may cause high-frequency disturbances. A basic feature of PVS is a lower RMS value for the pulse modulation component in the output voltage of the converter, compared to the typical value. Another important feature of the proposed converter is the ability of precise mapping of the output voltage to the reference (input) signal. The structure of the control circuit is relatively simple—no complex, digital components are used. Due to the high frequency of the SDM output bit-stream, the simulation model of the power stage of PVS is based on the power modules with gallium-nitride field effect transistors (GaN FETs). The work discusses the rules of PVS operations and the results from PVS simulation model studies as well as highlights the possible application fields for systems with a PVS.