Properties of powder core based inductors when utilised in a passive filter of the voltage source... more Properties of powder core based inductors when utilised in a passive filter of the voltage source inverter are investigated to highlight the importance of considering the soft-saturation nature of powder materials in determining the inductance when subjected to varying load current. Simulations were carried out in ANSYS Maxwell and Simplorer to understand the magnetic behaviour of inductors under pulse width modulation in a three-phase inverter. Variation of the effective inductance due to soft saturation nature of the powder cores is utilised to achieve the inductance demanded by the passive filter at the design stage.
LCL-filters are preferred over conventional L-filters for grid-connected voltage-source inverters... more LCL-filters are preferred over conventional L-filters for grid-connected voltage-source inverters (VSIs) due to their superior harmonic attenuation and smaller filter size and weight. The LCL-filter design process is complex and takes an iterative approach due to the considerations of resonance damping, reactive power compensation, harmonic attenuation limits, etc. This paper analyses the parameters of LCL-filter design in order to understand its significance in grid-connected applications. Secondly, based on the analysis, relationships between the resonance frequency, attenuation of switching ripple, reactive power production, and the ratio between the grid-side inductor and the inverter-side inductor are used to realize a simple LCL-filter design algorithm. The design considers LCL-filter as a single filtering unit rather than individual filtering contributions from passive components. The design is verified by simulations in MATLAB and validated experimentally via a hardware prototype. Results demonstrate the efficacy of the proposed method in terms of total harmonic distortion, harmonic attenuation, and reactive power compensated.
Current source inverter (CSI) is an alternative option to a voltage source inverter (VSI) for gri... more Current source inverter (CSI) is an alternative option to a voltage source inverter (VSI) for grid interfacing of distributed generation (DG) systems. However, literature lacks proper controller tuning procedures for grid-connected CSI that take into consideration the effects of control and sample delays when implemented using a digital signal processors (DSP). This paper presents a step-by-step approach in determining the controller gains by analyzing the system in discrete domain. Furthermore, proportional resonant (PR) and proportional integral (PI) controllers are also considered in the analysis to better understand the advantages they offer in controlling grid-connected CSI. The accuracy of the calculated gains are verified both through bode plots and Matlab simulations.
Grid-connected current source inverter (CSI) employs CL-filter to meet the harmonic limitations s... more Grid-connected current source inverter (CSI) employs CL-filter to meet the harmonic limitations set by IEEE 519-1992 and IEEE 1547-2008. However, parameter design for the CL-filter is rarely studied and no formalized approaches are followed. Therefore, this paper identifies the limitations in designing CL-filters for a single-phase grid-connected CSI and presents a complete design procedure which considers reactive power compensation, harmonic attenuation and optimization of the filter parameters. The design is validated by simulation in MATLAB.
Properties of powder core based inductors when utilised in a passive filter of the voltage source... more Properties of powder core based inductors when utilised in a passive filter of the voltage source inverter are investigated to highlight the importance of considering the soft-saturation nature of powder materials in determining the inductance when subjected to varying load current. Simulations were carried out in ANSYS Maxwell and Simplorer to understand the magnetic behaviour of inductors under pulse width modulation in a three-phase inverter. Variation of the effective inductance due to soft saturation nature of the powder cores is utilised to achieve the inductance demanded by the passive filter at the design stage.
LCL-filters are preferred over conventional L-filters for grid-connected voltage-source inverters... more LCL-filters are preferred over conventional L-filters for grid-connected voltage-source inverters (VSIs) due to their superior harmonic attenuation and smaller filter size and weight. The LCL-filter design process is complex and takes an iterative approach due to the considerations of resonance damping, reactive power compensation, harmonic attenuation limits, etc. This paper analyses the parameters of LCL-filter design in order to understand its significance in grid-connected applications. Secondly, based on the analysis, relationships between the resonance frequency, attenuation of switching ripple, reactive power production, and the ratio between the grid-side inductor and the inverter-side inductor are used to realize a simple LCL-filter design algorithm. The design considers LCL-filter as a single filtering unit rather than individual filtering contributions from passive components. The design is verified by simulations in MATLAB and validated experimentally via a hardware prototype. Results demonstrate the efficacy of the proposed method in terms of total harmonic distortion, harmonic attenuation, and reactive power compensated.
Current source inverter (CSI) is an alternative option to a voltage source inverter (VSI) for gri... more Current source inverter (CSI) is an alternative option to a voltage source inverter (VSI) for grid interfacing of distributed generation (DG) systems. However, literature lacks proper controller tuning procedures for grid-connected CSI that take into consideration the effects of control and sample delays when implemented using a digital signal processors (DSP). This paper presents a step-by-step approach in determining the controller gains by analyzing the system in discrete domain. Furthermore, proportional resonant (PR) and proportional integral (PI) controllers are also considered in the analysis to better understand the advantages they offer in controlling grid-connected CSI. The accuracy of the calculated gains are verified both through bode plots and Matlab simulations.
Grid-connected current source inverter (CSI) employs CL-filter to meet the harmonic limitations s... more Grid-connected current source inverter (CSI) employs CL-filter to meet the harmonic limitations set by IEEE 519-1992 and IEEE 1547-2008. However, parameter design for the CL-filter is rarely studied and no formalized approaches are followed. Therefore, this paper identifies the limitations in designing CL-filters for a single-phase grid-connected CSI and presents a complete design procedure which considers reactive power compensation, harmonic attenuation and optimization of the filter parameters. The design is validated by simulation in MATLAB.
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Papers by Moin Hanif