Control design issues in grid-connected single -phase converters, with the focus on power factor correction
Honkanen, Jari (2020-09-25)
Väitöskirja
25.09.2020
Lappeenranta-Lahti University of Technology LUT
Acta Universitatis Lappeenrantaensis
School of Energy Systems
School of Energy Systems, Sähkötekniikka
Kaikki oikeudet pidätetään.
In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of Lappeenranta-Lahti University of Technology LUT's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_ standards/publications/rights/rights_ link.html to learn how to obtain a License from RightsLink.
In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of Lappeenranta-Lahti University of Technology LUT's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_ standards/publications/rights/rights_ link.html to learn how to obtain a License from RightsLink.
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-335-548-4
https://urn.fi/URN:ISBN:978-952-335-548-4
Tiivistelmä
Electrical equipment is most commonly powered from a mains connection. The mains alternating voltage is rectified, isolated, and regulated in a power supply. The power supply acts as an interface between the mains voltage and the powered equipment. In addition to protecting the equipment from the mains voltage, the power supply isolates the mains connection from the distortions of the powered equipment. The protection against distortion is accomplished by controlling the voltages inside the power supply and the shape of the current drawn from the mains.
In many cases, the simplest control loop design will suffice, but a more elaborate control loop design is usually needed to meet all the design requirements. The current loop performance of the digitally controlled power factor correction is improved with a simple feedforward term. The idea for the proposed solution stems from the Lyapunov control theory.
The voltage loop performance of the power factor correction is improved by using a fuzzy nonlinear controller. The controller is simple to implement, as the underlying solution is to schedule the gains of two different PI controllers with the error between the measurement and the reference. Application of the presented controller simplifies the control design as the control designs for the steady-state and transient performance are decoupled, allowing the control to yield a fast transient with a low distortion, which are typically mutually exclusive. With a linear control, the dynamics of the DC link is a choice between a low distortion and a fast transient performance.
Further, this doctoral dissertation discusses the benefit of a digital control platform with the option to optimize the feedback measurement. The idea of proper timing of the current measurement, thereby minimizing the effects of anti-alias filtering, is investigated in the case of current measurement in a grid-forming inverter. The benefit of the proper timing of the measurement and filter design is a reduction in noise by −20 dB in the current measurement with a minimal phase delay.
All of the results obtained in the study were verified by extensive experimental measurements to validate the achieved performance and show that the algorithms and methods provide benefits in an actual setting.
In many cases, the simplest control loop design will suffice, but a more elaborate control loop design is usually needed to meet all the design requirements. The current loop performance of the digitally controlled power factor correction is improved with a simple feedforward term. The idea for the proposed solution stems from the Lyapunov control theory.
The voltage loop performance of the power factor correction is improved by using a fuzzy nonlinear controller. The controller is simple to implement, as the underlying solution is to schedule the gains of two different PI controllers with the error between the measurement and the reference. Application of the presented controller simplifies the control design as the control designs for the steady-state and transient performance are decoupled, allowing the control to yield a fast transient with a low distortion, which are typically mutually exclusive. With a linear control, the dynamics of the DC link is a choice between a low distortion and a fast transient performance.
Further, this doctoral dissertation discusses the benefit of a digital control platform with the option to optimize the feedback measurement. The idea of proper timing of the current measurement, thereby minimizing the effects of anti-alias filtering, is investigated in the case of current measurement in a grid-forming inverter. The benefit of the proper timing of the measurement and filter design is a reduction in noise by −20 dB in the current measurement with a minimal phase delay.
All of the results obtained in the study were verified by extensive experimental measurements to validate the achieved performance and show that the algorithms and methods provide benefits in an actual setting.
Kokoelmat
- Väitöskirjat [1072]