Abstract
The concept of hybrid control has been introduced, in which the analog implementation of the control algorithm is combined with a digital algorithm for determining the PWM duty cycle. Single-loop PD and PID control systems are compared to a double-loop architecture with additional capacitor current sensing for both digital and hybrid controller realizations. The performance is measured as the THD value under resistor-capacitor rectifier load. It has been shown that a properly constructed continuous-time model of a digital controller with a PWM power converter behaves like the actual discrete-time system, which allows for a simple controller analysis and design. The role of a PWM type for capacitor current feedback is emphasized. The simulation models of a real inverter are presented, which are used to tune the controllers and to evaluate the control performance for both rectifier and abruptly changing resistive load. The obtained solutions achieve the THD values comparable to the VSI without load. The results are contrasted with the control methods based on resonant filters.
Highlights
It has been shown that a properly constructed continuous-time model of a digital controller with a Pulse Width Modulated (PWM) power converter behaves like the actual discrete-time system, which allows for a simple controller analysis and design
DC/AC Voltage Source Inverters (VSI) are commonly used as a basic component of Uninterruptible Power Supply (UPS) units to convert the DC energy contained in batteries into the appropriate AC voltage when the mains power fails
Blurring is seen in the original PWM output around the QCT one, making the difference between their Total Harmonic Distortion (THD) values shown in Figure 16, where the THD jump in fs is due to the residual presence of fs in vout
Summary
DC/AC Voltage Source Inverters (VSI) are commonly used as a basic component of Uninterruptible Power Supply (UPS) units to convert the DC energy contained in batteries into the appropriate AC voltage when the mains power fails. Due to the ever increasing availability of renewable energy sources, single-phase UPS inverters have found wide application in supplying local electric power networks. The performance of the inverter is usually measured as the Total Harmonic Distortion (THD) value of the output voltage under the standard non-linear rectifier resistor-capacitor (RC) load. Another measure of performance is the distortion of the output voltage caused by a sudden decrease or increase of the resistive load. We use both performance indicators regardless of the source of the distortion
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
