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In this work, different current limiting methods for grid forming inverters are presented and theoretically analyzed. A transient non-linear virtual impedance is introduced and compared with the standard current limiting methods in synchronous rotating reference frame. Their performance is evaluated by means of real time simulation for standalone and parallel operation of an inverter with a synchronous...
Distributed Generation in Low Voltage grids has raised the concern of unintentional islanding and its probability has increased due to the newly introduced standards for generators, which in particular impose wider frequency and voltage ranges and active and reactive power support capabilities using of P/f and Q/V droop characteristics. Anti-islanding protections that each inverter is equipped with,...
This paper investigates the uncontrolled generator (UCG) operating characteristics of permanent magnet (PM) synchronous machine drives using current-source inverters with normally-on switches. This special mode occurs when a PM machine is spinning at a high speed and gating signals are simultaneously removed from all of the inverter switches. This investigation shows that the UCG operating characteristics...
This paper deals with an open-circuit IGBTs faults diagnostic method that is dedicated for three-phase two-level voltage inverter fed vector controlled induction motor drive systems. The presented technique is based on a transient analysis of a reference voltage space vector in a stationary reference frame and it does not require an extra sensors application. The diagnostic algorithm ensures to detect...
A space-vector hysteresis modulation (SVHM) technique is presented in this paper for three-level neutral-point-clamped (TL-NPC) multilevel inverter for active power filter (APF) applications. The main responsibility of this modulation technique is to force the actual current to reach the reference current and, simultaneously, balance the capacitor voltages. This scheme is implemented in the stationary...
A hybrid battery system within an energy storage system is gaining interests because it provides multiple advantages compared to the traditional single type battery system in terms of cost, volume, performance, and flexibility. Moreover, motivation on using second life ex-transportation batteries on the grid applications has given a boost on using hybrid batteries because vehicle batteries could be...
Voltage ripple and high voltage transients appear in the high voltage supply system of electrical vehicles. Their origins are switching operations of power electronics and load cycles of high voltage components. This paper presents EMC requirements for these effects from a car manufacturer's point of view based on vehicle measurements. Using these requirements, component test setups can be designed...
In the near future, transmission grids will include an increasing share of directly connected voltage source converters. These systems should be able to support the utility grid autonomously. The present paper reviews the most popular approaches to address the challenge of proper load sharing amongst multiple parallel inverters applied to the utility grid case. Originally developed for Microgrid or...
Currently, the standards used to calculate the short circuit (SC) current ignore the contribution of DC systems to the SC current when short-circuit faults occur in an AC systems. With the rapid development of High Voltage Direct Current systems (HVDC), it has become important to determine whether the contribution of the HVDC system can be ignored when calculating the SC current. This study investigates...
Using the characteristic difference of transient energy, a transient energy based directional unit protection is proposed. Assuming the positive direction of current is from DC busbar to DC line, for an internal line fault, the detected transient energies on both ends of the line are all negative, which denote the positive direction fault. When an external fault occurs, the transient energy on one...
This paper provides recommendations for volt-VAr and voltage ride-through needs from distributed energy resources (DERs) to contain fault induced delayed voltage recoveries (FIDVRs) events and help stabilize the grid. FIDVR events can potentially cause chain reactions and destabilize the grid. Additionally, it will provide typical residential air conditioner (RAC) unit performance during voltage transients...
A comprehensive data set of heavy-ion induced single-event transients has been collected for inverter chains fabricated in the IBM 32nm partially-depleted silicon-on-insulator technology across various bias voltages, transistor variants, ion energies and angles of incidence.
This paper presents an optimized design example of high efficient inverter which consists of Silicon-Carbide (SiC) Metal-Oxide-Semiconductor-Field-Effect-Transistor (MOSFET) and optimized gate driver for SiC-MOSFETs. The purpose of this research is to optimize design of SiC-MOSFETs inverters. We confirmed that the proposed inverter is capable of operating efficiently with experimental results. The...
Single-phase inverters need large bulk DC link electrolyte capacitors which reduce the life time of the converter circuit. Furthermore, there is a safety need for low input voltage in photovoltaic (PV) residential applications. A new cascaded power-decoupling topology is proposed in this paper with film capacitors and high step-up ratio. The topology is based on cascaded double boost; the output of...
The Navy is considering alternative power system architectures to traditional 60 Hz Medium Voltage Alternating Current (MVAC) power systems for shipboard operation. One alternative architecture being strongly considered for several reasons, is Medium-Voltage Direct Current (MVDC). With that consideration, comes the need for effective electrical fault risk prevention and mitigation. This paper explores...
In virtual vector control schemes for singlephase current-regulated voltage source inverters, a transient disturbance may be induced due to the time-delay in the virtual orthogonal signal. This disturbance deteriorates the dynamic current-tracking capability and power quality. A unified scalar model is developed to analyze the phenomenon. Based on this model, an improved control scheme with a pre-compensator...
Instead of MOSFET Single Electron Transistor (SET) can be used as a voltage controlled switch. The current flowing through a SET is the result of electron tunneling through tunnel junctions of its source and drain. So the supply voltage requirement is also very low. As a result, the power consumption across a Single Electron Transistor is ultra-low in comparison to that of a MOSFET. In this research...
This paper emphasises the modelling and control of a voltage source converter (VSC) for three phase grid connected PV system. The transfer functions for inner current control and outer DC link voltage control for VSC are derived. The controllers for VSC are designed based on PI and K factor control methods and the performance of VSC using both the methods are presented with the simulations performed...
In this work a method to detect stator insulation degradation of traction drives based on analyses of the transient current reaction caused by inverter switching is proposed. Two simple excitation methods are proposed to analyze the state of the inter-turn insulation as well as the groundwall insulation. With the standard hall-effect based closed loop current transducers used for the control of the...
This paper investigates the single-switch short-circuit fault response of a permanent magnet (PM) machine drive using a current source inverter (CSI). The CSI offers some appealing advantages over conventional voltage-source inverters (VSIs) during short-circuit fault conditions originating inside the inverter. Two post-fault strategies are investigated in this paper, consisting of either: 1) turning...
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