Evgenije Adzic

HIL Evaluation of Power Flow Control Strategies for Energy Storage Connected to Smart Grid Under Unbalanced Conditions

This paper proposes two power flow control algorithms for a grid-connected voltage source converter used as part of the energy storage for a smart grid under unbalanced voltage conditions. Both algorithms are improvements of the dual vector current control algorithm (DVCC). The first proposed algorithm, DVCC_CL, optimizes the method of limiting phase currents for the duration of voltage unbalance. The second proposed algorithm, DVCC_HB, provides high bandwidth control of active and reactive power. Which of the two proposed algorithms is the better choice depends on the grid code requirements and the constraints imposed by the particular energy storage system which the inverter connects to the grid. The operation of both algorithms was verified within the framework of an ultralow-latency hardware-in-the-loop emulator, which makes accurate analysis of converter behavior safe and easy for any grid conditions.

Development of High-Reliability EV and HEV IM Propulsion Drive With Ultra-Low Latency HIL Environment

This paper proposes an improved and robust method of minimizing the error in propulsion-drive line-currents that are reconstructed from a single dc-link current measurement. The proposed algorithm extends and then shortens the relevant phase pulse-widths in order to provide optimal sampling of the dc-link currents in two consecutive pulsewidth modulation (PWM) periods. The proposed PWM pattern control enables an improved sampling method which cancels offset jitter-like waveform errors present in all three reconstructed line-currents, which is due to a specific combination of nonsimultaneously sampled dc-link current and line-current PWM ripple. The improvement in induction motor drive accuracy using a single current-sensor and no shaft sensor (as proposed in this paper), over that of conventional methods, is shown. Thanks to an ultra-low latency hardware-in-the loop (HIL) emulator, the proposed algorithm, its implementation on a DSP processor, code optimization and “laboratory” testing were all merged into one development step. In order to perform final tests of the proposed current-reconstruction algorithm and to verify the usefulness of the developed HIL platform by means of comparison, experimental results obtained on a real hardware setup are provided.

Grid-connected Voltage Source Converter operation under distorted grid voltage

This paper proposes new control strategy for grid connected three-phase Voltage Source Converter (VSC). The strategy is designed to overcome problems of conventional voltage oriented VSC control operating under distorted grid voltage. Proposed control strategy cancels the influence of characteristic distribution grid voltage harmonics, and injects close to sinusoidal current to the grid, with permitted current waveform distortion level.

Hardware-in-the-Loop optimization of the 3-phase grid connected converter controller

This paper illustrates how the HIL devices of the latest generation can be used to aid in the design, optimization and quality assurance of PE controllers. Such devices can have as low as 0.5μs fixed time step and a PWM sampling frequency that can be as low as 6ns which makes them ideal to support controller development processes from the early design stage all the way to type testing and release testing stage.

Optimum fuzzy logic control of induction generator in wind turbine application

This paper deals with fuzzy logic control of induction generator in wind turbine application in order to extract maximum power from the wind. Fully-controlled wind turbine consists of induction generator and back-to-back converter which is used to maximize the power output and enhance system performance. The advantages of using fuzzy controller are universal control algorithm, fast converging, parameter insensitivity, and accepting of noisy and inaccurate signals. Performance has been evaluated in details using Matlab/Simulink.

High-fidelity real-time hardware-in-the-loop emulation of PMSM inverter drives

We describe the design, implementation, and experimental validation of an ultra-fast real-time hardware-in-the-loop emulation of a permanent magnet synchronous machine (PMSM) inverter drive. The power electronics converter and machine are modeled using a flexible piecewise linear state space approach and are simulated in hard real-time with 1 μs time step, which enables high-fidelity modeling of converter switching dynamics, including dead time and fully rectifying mode. We validate the fidelity of the real-time PMSM drive emulation by making real-time comparisons with a reference hardware model of a PMSM drive (scaled down system rated at 2.7 A and 200 V). Additionally, we experimentally demonstrate the capability of the hardware-in-the-loop PMSM drive emulation under various operating scenarios, including steady state, transient, and fault conditions.

Performance evaluation of field angle correction scheme for high speed sensorless IM

This paper presents a shaft-sensorless vector controlled IM drive equipped with novel field angle correction method. This method is suitable to be used in ultra high speed region in which most of the drive outputs are in limit and standard flux correction schemes tend to fail. In the case of any flux amplitude error, novel scheme corrects the field angle instead of flux producing current which was found to be more beneficial, especially when vector drive is at the border of voltage and/or current limits. In this paper, scheme performance was investigated for typical source of field orientation error in high speed region, the leakage inductance variation. Comparison of the proposed scheme performance with standard solution is given. Simulation and experimental results are presented.

Space vector modulated three-phase current source converter for DC motor drive

The main disadvantage of applying a standard network driven thyristor rectifiers for a DC motor speed control is the fact that such drives loads the network with reactive power and due to its nonlinear structure network current is nonsinusoidal with a higher harmonics content. Modern development of electronic power components, primarily IGBT and MOSFET switches, allows the replacement of a thyristor three-phase rectifiers with an active converter with a six fully-controlled switches that provides usage of switching frequencies significantly above the network frequency. By suitable control algorithm PWM converter can provide sinusoidal input current waveform, which significantly contributes to the reduction of higher harmonics content in the network The paper presents the results obtained by simulation and experiment for the case of application of an active PWM converter driven DC motor for speed control. Results analysis clearly shows the benefits of the active PWM converter application.

Real-time power-reference tracking method for PV converters

Due to the increasing presence of renewable inertia-less energy sources, power electronics interfaces are required to exploit their flexibility in order to support the overall grid quality of service. One way to achieve this, is that power converters are capable of actively track active and reactive power-setpoints, that are computed by suitable centralized or decentralized control schemes. In this paper, we propose a novel algorithm which enables the control of a boost converter to achieve arbitrary active-power reference tracking for photovoltaic plants, not operating in maximum power point tracking (MPPT) mode.

Educational framework for a motor drive control systems: Design and performance assessment

In this paper, an emulation based electrical drive laboratory for graduate and undergraduate power engineering students and practicing engineers is presented. The virtual laboratory is realized by means of Hardware‐In‐the‐Loop (HIL) system, which is increasingly recognized as an effective approach in the design of power electronics control. Control of induction motor, as the most widely used machine including main and side effects is examined. In order to perform experiments gradually, software development framework which provides modular and incremental DSP programming possibilities (from basic to advanced levels) is given. Digital controller design procedure combined with appropriate emulated power stage, and followed by experimental results is presented in detail. In addition to conventional test procedure, scripting method implemented through Application Programming Interface (API) is shown. The benefits of remote laboratory approach is described in the case of collaboration of multiple teams. The proposed approach can be used as additional or completely self‐contained tool for research and education of electrical drive control.