Dinavahi, V.R.; Reza Iravani, M.; Bonert, R.
This paper presents a new approach for the real-time digital simulation
of power electronic controllers in power systems. Digital controllers
for power electronic systems present a problem when testing in real-time
using a digital simulator due to the discrete nature of their outputs
which are not necessarily in synchronism with the time step of the simulator.
The proposed algorithm combines the variable step-size numerical integration
method with linear interpolation for the synchronization of a real-time
digital simulator and a digital controller. It is shown that lack of
such synchronization leads to inaccurate simulation results, specifically
with regard to the fundamental and harmonics of the voltage and current
signals. Sampling theory is used to model the interaction between a
digital simulator and a digital controller. A pulse width modulated
(PWM) voltage source converter (VSC) based reactive power compensator
system is used as an illustrative example for the simulation.
Chunting Mi; Slemon, G.R.; Bonert, R.
In permanent magnet (PM) synchronous machines, iron losses form a larger portion of the total losses than in induction machines. This is partly due to the elimination of significant rotor loss in PM machines and partly due to the nonsinusoidal flux density waveforms in the stator core of PM machines. Therefore, minimization of iron losses is of particular importance in PM motor design. This paper considers the minimizing of iron losses of PM synchronous machines through the proper design of magnets and slots, and through the choice of the number of poles. Both time-stepped finite element method (FEM) and the iron loss model from a previous study are utilized in this paper to draw the conclusions.
Chunting Mi; Slemon, G.R.; Bonert, R.
Zubieta, L.; Bonert, R.
The double-layer capacitor (DLC) for power applications
is a new device. A simple resistive capacitive equivalent circuit is insufficient
to characterize its terminal behavior. Based on physical reasoning, an
equivalent circuit is proposed to provide the power electronics engineer
with a model for the terminal behavior of the DLC. The equivalent circuit
model consists of three RC branches, one of them with a voltage-dependent
capacitance. A method to identify the circuit parameters is presented.
Measurements of carbon-based DLC's for power applications are presented,
analyzed, and the equivalent circuit response is compared with experimental
results.
Kouroussis, D.; Bonert, R.; Dawson, F.P.
This paper presents experimental results for a pulsed vortex water wall high pressure arc lamp. The power source consists of a DC ignitor connected in series with a sustaining source. The ignitor is shorted after a sustaining current is achieved, followed by the connection of a regulated pulsed current source connected in parallel with the sustaining source. The application of this lamp in rapid thermal processing systems dictates that the interpulse period of the pulsed source be made as short as possible. Experiments have been performed with and without the sustaining source. Arc overvoltage after the current is reapplied becomes larger as the interpulse period is made longer. Overvoltages are higher if no sustaining source is used during the interpulse period. An acoustic resonance is observed with a duration equal to the axial convective transit time. A sustaining source may not be required based on the results of the experiments.
Zubieta, L.; Bonert, R.
Double-layer power capacitors (DLCs) are very attractive
in several applications and specially in high power load shaving. However,
the electrical behaviour of these devices is considerably different from
the traditional capacitors. Due to the low voltage of the single cell
DLC, many devices have to be connected in series to reach the technically
required voltages. This paper presents the aspects to be considered in
building an energy storage system based on double-layer capacitors, especially
those factors that may affect the voltage sharing among capacitors. Furthermore,
the paper presents the experimental results from a 400 kW sec energy storage
system built with 100 double-layer capacitors connected in series.
Bonert, R.; Rajakaruna, S.
A capacitor-excited induction generator used with a hydraulic
turbine in a stand-alone generating system can provide high quality voltage
and frequency control not matched by other small generating units. This
is achieved without a turbine governor by using a controllable additional
impedance on the load side. The control is achieved using a static power
converter. The analysis of the system and the design of the power and
control system are presented. Measurements from an experimental unit are
provided to verify the predicted performance.
Bonert, R.
The 4th year course 'Power Systems Control' at the University of Toronto includes a laboratory familiarizing the student with the function and use of static converters for the control of power systems. This paper describes the concept of the laboratory and the required equipment. The experiments are discussed in detail to demonstrate the possibility to teach the different aspects of power systems control with static converters.
Zubieta, L.; Bonert, R.
The double-layer capacitor (DLC) for power applications is a new device. A simple resistive capacitive equivalent circuit is insufficient to characterize its terminal behaviour. Based on physical reasoning, an equivalent circuit is proposed to provide the power electronics engineer with a model for the terminal behaviour of the DLC. The equivalent model consists of three Re branches, one of them with a voltage dependent capacitor. A method to identify the circuit parameters is presented. Measurements of carbon-based DLCs for power applications are presented, analysed, and the equivalent circuit response is compared with experimental results.