Investigation of parallel-connected GaN E-HEMT VSI-based servo drives

2022-1-19
Yürük, Hüseyin
Show full item record
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
304
views
536
downloads
Nonlinearities in voltage source inverters (VSIs) are thought to be the primary cause of output voltage distortions which cause low-order harmonics in the output current. These nonlinearities also considerably degrades control performance and system stability for low-speed applications with low-inductance motors, particularly when the system operates in the low-torque area. The impact of the nonlinearities on the phase current and current control of a silicon (Si) metal-oxide-semiconductor field-effect transistor (MOSFET) based VSI are examined in this thesis using a coreless permanent magnet synchronous motor (PMSM). To address this issue, a gallium nitride (GaN) enhancement-mode high electron mobility transistor (E-HEMT) based VSI is proposed. Based on the results, a GaN E-HEMT VSI-based servo drive is being developed to replace its Si MOSFET VSI-based counterpart. It is about half the size of the previous one, allowing for the use of two servo drives in parallel rather than one for redundancy. The use of parallel-connected servo drives offers the benefit of increased torque capacity, reliability, redundancy, and modularity. Smaller variances in the system clocks of the separate microcontrollers, asynchronous pulse width modulation (PWM) carrier signals, and hardware differences, on the other hand, might cause non-identical output voltages of the parallel modules, resulting in circulating currents. These circulating currents limit parallel operation, increase power consumption, induce imbalanced power distribution, and degrade control performance. A fault‐tolerant parallel‐connected GaN E-HEMT VSI based servo drive scheme is proposed to reduce the circulating currents and to eliminate the need for extra inductors at the output and separate DC supplies at the input of the inverters. Various experimental tests are conducted with up to six parallel-connected servo drives and a PMSM for validation.
nonlinearity in VSIs, dead time, coreless PMSMs, GaN E-HEMT VSI-based servo drive, parallel-connected VSIs
https://hdl.handle.net/11511/96074
Graduate School of Natural and Applied Sciences, Thesis

Suggestions

Comparison of the Effects of Nonlinearities for Si MOSFET and GaN E-HEMT Based VSIs
Yuruk, Huseyin; Keysan, Ozan; Ulutas, Baris (2021-07-01)
Nonlinearities in voltage source inverters (VSIs) such as; dead time, switching time, delay time, voltage drops on the power switches, parasitic capacitance, etc., are considered to be the main sources of the output voltage distortions. These distortions result in low-order harmonics in the output current, which in turn increase core losses and create torque ripples. In particular, for low-speed applications with low-inductance motors, the control performance and the stability of the system degrades substan...
Performance analysis and comparison of reduced common mode voltage PWM and standard PWM techniques for three-phase voltage source inverters
Un, E; Hava, Ahmet Masum (2006-03-23)
This paper investigates the performance characteristics of the reduced common mode voltage (RCMV) PWM methods for three phase voltage source inverters and provides a comparison with the standard PWM methods. PWM methods are reviewed and their pulse patterns and common mode voltage patterns illustrated. The AC output current ripple, DC link input current ripple, and output voltage linearity characteristics of each modulation method are thoroughly investigated by analytical methods and simulations. The analys...
A Proposal for Improving Efficiency of Inverter Driven Electrical Motors
Ertan, Hulusi Bülent (2011-07-28)
Conventional inverter output has PWM output. This pulsed output waveform reduces insulation life time, contributes to quick degradation of the bearings and also is often source of acoustic noise. Furthermore, losses of PWM inverter-driven motors increase. In this paper a novel topology is proposed which is capable of generating a sinusoidal waveform, with low harmonic distortion. If the proposed method is used for driving motors, motor efficiency increases due to reduced losses and lifetime of the motor may...
Investigation of subsynchronous resonance risk in the 380 kv Turkish electric network
Ozay, N.; Güven, Ali Nezih (null; 1988-12-01)
Subsynchronous resonance (SSR) occurs when a resonant frequency of a series compensated transmission system interacts with a natural frequency of the turbine prime mover. This form of SSR is referred to as torsional interaction which, under certain conditions, may become self-excited and cause serious damage to electrical equipment and turbine shafts. The presence of a thermal power plant (Kangal) in the close vicinity of a group of series capacitors in Eastern Turkey necessitated a careful investigation of...
Analysis and Characterization of DC Bus Ripple Current of Two-Level Inverters Using The Equivalent Centered Harmonic Approach
Ayhan, Ufuk; Hava, Ahmet Masum (2011-09-22)
The dc bus PWM ripple current of three-phase two-level voltage source inverters is a function of the PWM method, the load current magnitude, power factor angle, and the modulation index. Thus, the ripple current characteristics are highly involved and difficult to understand. Using the double Fourier integral approach, this paper investigates the ripple current characteristics thoroughly for a wide range of operating conditions and PWM methods. Then, the equivalent harmonic approach is used to lump the ripp...
Citation Formats
H. Yürük, “Investigation of parallel-connected GaN E-HEMT VSI-based servo drives,” Ph.D. - Doctoral Program, Middle East Technical University, 2022.
METU IIS - Integrated Information Service open@metu.edu.tr