Bulent Sarlioglu

• Ph.D.
• Managing Director at University of Wisconsin–Madison

This article proposes a new pulse-width modulation (PWM) scheme that reduces common-mode (CM) voltage and switching losses simultaneously in CSI. The proposed PWM (i.e., reduced voltages PWM: RVM) reduces CM voltages and switching losses by selecting the optimal zero current vector and PWM sequence based on the CSI output voltage conditions. This a...

This paper presents an investigation of the effects of the gate drive resistance on the performance of the balanced inverter used for common-mode voltage cancellation. A simplified analytical common-mode voltage model that incorporates the circuit stray inductances is derived to capture the impact of the gate drive resistance on the effectiveness o...

The rising demand for wide bandgap (WBG) devices and the growing need for compact motor drives in electric vehicles (EVs) have escalated the challenges associated with common-mode (CM) current, and electromagnetic interference (EMI) in EV motor drives. This article investigates the impact of concentrated winding (CW) and toroidal windings (TW) on m...

This article proposes a new dc-link resistor-capacitor (RC) snubber design method that overcomes three challenges in the conventional eigenvalue-based design methods (i.e., not universally applicable for various parasitic circuit parameters, challenging to consider zeros in the design process, and requiring numerical iterations). The proposed dc-li...

This paper addresses the underexplored field of self-sensing rotor position estimation control methods in current-source inverter (CSI) drives, an increasingly appealing topology due to advancements in monolithic wide bandgap four-quadrant switches. While numerous techniques have been devised for voltage source inverters (VSIs), the pulsating vecto...

This paper proposes an advanced approach to cooling high-performance electric traction motors by utilizing the two-phase immersion cooling. The method involves immersing a stator package in a dielectric liquid, featuring higher heat transfer rates through phase change from liquid to vapor induced by heat generated by the motor components. Compared...

This paper presents a novel in-core cooling method for yokeless and segmented armature (YASA) axial flux machines to address the challenges posed by high temperatures in these machines, thereby unlocking their full potential. The proposed in-core cooling method involves forming cooling channels within each laminated stator core segment, through whi...

This paper presents a method to detect and diagnose an inter-turn short circuit in interior permanent magnet synchronous machines. The proposed method detects the inter-turn short circuit fault using a current observer to estimate a disturbance related to the fault, defined as a fault index current. The fault index current estimates in the rotor re...

The fight against global climate change demands the electrification of aircraft propulsion. One of the most significant and distinct challenges that future multi-megawatt electrified propulsion will face is high voltage at high altitudes, which could cause significant partial discharge and reduce the reliability of the propulsion system. Recognizin...

This paper proposes the concept of the topological equivalence between the commutation cells of a voltage source inverter (VSI) and a current source inverter (CSI) using duality and equivalent circuit transformation techniques. A switching resonance of CSI is analyzed and an effective three-phase RC damper is derived from the dc-link RC damper...

This paper proposes a novel six-phase permanent magnet (PM) motor drive with both phase- and parallel-redundancies for the highest-level of a fault-tolerant operation. The proposed motor drive can continuously operate without any increased ripple torque up to four arbitrary phase open-circuit failures except for a single unique case where two remai...

In pulsewidth-modulated (PWM) inverters, common-mode (CM) voltage and associated conducted CM electromagnetic interference (EMI) can cause motor bearing failures, ground leakage current, and audio susceptibility issues. When wide bandgap (WBG) devices are used to construct a voltage-source inverter (VSI), the CM EMI issues become more challenging....

In this article, proof of concept of interturn short circuit (ISC) detection and shorted turns current reduction with d -axis current injection along with torque compensation is shown. This article evaluates the feasibility of implementing the detection and compensation of an ISC in an interior permanent magnet synchronous machine fed by a two-le...

This article proposes a model for obtaining the failure path current and torque waveforms in synchronous machines with saliency under interturn short circuits (ISC). The variations of the magnetomotive force (MMF) due to an ISC can lead to changes in the inductances, which lead to errors when modeling motors with ISC. A compact approach based on co...

The adoption of wide bandgap (WBG) devices in power converters create challenging conducted common-mode (CM) electromagnetic interference (EMI) issues due to their fast-switching transients and high switching frequencies. This article focused on analysis and suppression of CM EMI for WBG-enabled three-phase current source converters (CSCs) consisti...

Conventional current-source inverters (CSIs) using silicon-based reverse-blocking (RB) switches typically suffer from high conduction loss, low switching frequency, and bulky size. New bidirectional (BD) switches (also called four-quadrant switches) built from wide bandgap semiconductor materials such as gallium nitride and silicon carbide offer bo...

Due to the high forward voltage drop of reverse-blocking (RB) switches, conventional current-source inverters (CSIs) typically suffer efficiency penalties. Bidirectional (BD) switches, on the other hand, can also block reverse voltages but with less conduction loss than RB switches, making them more attractive candidates for CSI switches. This arti...

An integrated motor-compressor synergistically combines a flux-switching permanent magnet (FSPM) machine with an axial-flow compressor by shaping the rotor poles of the motor into airfoils. The airfoil-shaped rotor functions as the rotor of a motor as well as the rotor of an axial-flow compressor. The airfoil-shaped rotor poles need to be skewed by...

Direct cooling of the windings in a motor using oil offers more effective thermal management than conventional alternatives and can therefore increase the torque density of electric machines; however, this technique is limited by the thermophysical properties of the oil. The use of a direct winding heat exchanger (DWHX) allows a glycol-water coolan...

View Video Presentation: https://doi.org/10.2514/6.2021-3306.vid The electrification of commercial aircraft propulsion requires the development of megawatt-class electrical machines possessing high power density, high efficiency, and effective cooling. These demands are explored in this presentation of a megawatt-class surface permanent magnet (SPM...

Four-quadrant (FQ) switches that have both bidirectional current and reverse-voltage blocking (RVB) capabilities are appealing candidates for use in current-source inverters (CSI) to significantly reduce the switch conduction losses. However, the FQ characteristics of these switches can create problems during switching events by causing transient o...

The objective of this paper is to evaluate the self-cooling performance of a novel integrated flux-switching PM (FSPM) machine with an airfoil-shaped rotor. The rotor of the proposed integrated machine is functioning as both a rotor of the motor as well as an axial fan. It rotates to draw air from the ambient into the rotor and accelerate the flow...

This paper develops a real-time loss minimizing control technique on induction machines for dynamic load profiles. Steady-state loss minimization has been well addressed. However, when the steady-state optimal control is applied to a highly dynamic load profile, more losses are induced during transients due to the slow rotor flux dynamics. Several...

Most permanent-magnet (PM) loss studies consider only eddy current loss and neglect hysteresis. In this paper, the hysteresis behavior of two NdFeB PM grades with different magnetic properties is assessed when applied in a PMSM. Data from vibrating sample magnetometer measurements and hysteresis modelling are used as a base. In addition to the main...

The objective of this paper is to propose the concept of and evaluate the potential performance of an integrated flux-switching permanent magnet (FSPM) motor-compressor that has rotor poles designed as airfoils to perform compression functions. The airfoil-shaped rotor functions as the rotor of both an electric motor and an axial-flow compressor. A...

This paper proposes a high-frequency injection (HFI) based dq-inductance estimation technique for synchronous machines. The d and q-axes inductance are estimated using a single HF injection between dq-axes, i.e., 45' injection angle. The d and q-axes incremental inductance variation over four quadrants dq-plane operating condition is evaluated. The...

A technology revolution is unfolding around us as every major mode of transportation is in some stage of electrification, whether on land, sea, or in the air. All of these transportation modes depend on electric machines that play critical roles in both propulsion systems as well as in a wide variety of accessory equipment. Fuel economy and reduced...

This paper presents a model-based design method for current controllers of pulse-width modulated converters. It demonstrates how the command-tracking and disturbance rejection behavior of current controllers must be designed separately via appropriate state-feedback and feedforward paths, as well as feasible references to yield an optimized system...

This study investigates the thermal impact of using different winding topologies and different winding encapsulation materials on dual‐stator 6/4 flux‐switching permanent magnet (FSPM) machine with water jacket cooling. The thermal performance of four different design cases are compared using lumped‐parameter thermal network models. The modelling o...