EPE Association: EPE 2019 - DS2f: Standard and Advanced Control Techniques for Power Converters I

EPE 2019 - DS2f: Standard and Advanced Control Techniques for Power Converters I
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 03: Measurement and Control > EPE 2019 - DS2f: Standard and Advanced Control Techniques for Power Converters I

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   A Smooth Switching control method Based on a Variable-Structure Multi- Resonant DC-DC Converter
By Mengying CHEN [View]
[Download]

Abstract: In this paper, based on a variable-structure multi-resonant DC-DC converter, a novel transient smoothcontrol method is proposed. Through the introduction of the gradual control idea, a drive signalgradual adjustment method is discussed. Consequently, smooth switching between different modes isrealized and the voltage fluctuation is suppressed effectively.

   Direct Multivariable Control of MMC Under Transient Conditions
By Daniel DINKEL [View]
[Download]

Abstract: Modular Multilevel Converters (MMC) have become state of the art in many demanding application fields, because of several essential advantages. Main drivers of further progress are improved semiconductors (Si and SiC), advanced submodule topologies and new control schemes. Fully electronic fault management and reduced capacitor size and footprint of the converters are essential future requirements. These issues enforce new control concepts with very fast response under transient and fault conditions. An advanced multivariable control concept meeting these requirements is presented. Extensive simulation results of the transient behaviour are given.

   Full State Feedback Control of Buck-type PWM Rectifier
By Lorenzo GIUNTINI [View]
[Download]

Abstract: Buck-type PWM rectifiers require an input LC filter, intrinsically exposed to resonance. Converter control needs to dominate the LC filter resonance. This paper details full state feedback controller design for the rectifier. Particularly, the paper demonstrates the equivalence of full state feedback control with PI controller plus active damping. Converter operation is validated experimentally on a 60 kVA rated rectifier.

   Gradient-Based Fixed Switching Frequency Direct Model Predictive Control for Grid-Connected Converters with LCL Filters
By Mehrdad NAHALPARVARI [View]
[Download]

Abstract: This paper presents a direct model predictive control (MPC) scheme for a three-phase two-level grid-connected converter with an LCL filter. Despite the absence of a modulator, a fixed switching frequency and a discrete current harmonic spectrum are achieved. With a refined objective function of the optimization problem underlying MPC, grid current distortions comparable to those of carrier-based pulse width modulation (CB-PWM) in idealized conditions are produced. Moreover, the grid current harmonics meet the stringent limits imposed by grid standards. A performance evaluation is conducted to highlight the potential benefits of the proposed method.

   High Efficiency single-phase Dual-Active-Bridge AC/AC Converter
By Raeed RAHMOUN [View]
[Download]

Abstract: This paper presents a 4 kVA single-phase isolated (230V/230V) ac/ac Dual Active Bridge (DAB)converter prototype suitable for Solid State Transformer (SST) applications. A solution for inductiveload is introduced and a novel control scheme based on gain scheduling approach is employed toimprove the DAB overall efficiency. Efficiency optimization is done based on global Zero-VoltageSwitching (ZVS) analysis of the DAB converter operating range for dual phase-shift modulation. Inthis analysis, minimization of both the Reactive Power per Switching Cycle (RPSC) and the rmscurrent of the high frequency inductance is taken into consideration to get the optimal modulationparameters. Simulation results are presented to validate the proposed control scheme.

   Impedance Modeling and Stability Analysis of Three-phase Grid-connected Inverter with LCL Filter in dq-frame
By Yang HUA [View]
[Download]

Abstract: To study the system stability of three-phase grid-connected inverter with LCL filter, an impedance modeling method is established in this paper. This model built in the dq-frame considers the phase locked loop, the current control loop and what's more, the decoupling control method. Based on it, the output impedance model with active damping strategy is established. The accuracy of the model is verified by frequency scanning. After that, the Generalized Nyquist Criterion is applied to analyze the influence of controller parameters and the control strategy on the system stability. It is theoretically proved that decoupling control method can improve the system stability and the resonance peak can be restrained after adding active damping strategy. The validity of the model and the theoretical analysis are verified by simulations and experimental results, illustrating that the model proposed in this paper can be well used to analyze the three-phase LCL-type grid-connected inverter with decoupling control method and active damping strategy.

   Model Predictive Control with Space-Vector Modulation for a Grid-Connected Converter with an LCL-Filter
By Adriaan SADIE [View]
[Download]

Abstract: This paper presents an indirect model predictive control (MPC) strategy with space-vector modulation (SVM). The controller is used to control a high-power voltage-source inverter (VSI), connected to the grid via an LCL-filter. The controller evaluates a multi-variable and convex cost function over a long prediction horizon in order to determine an optimal sequence of references for a space-vector modulator. The MPC strategy is tested in a Matlab simulation. The results of the simulation show excellent steady-state behaviour as well as a fast response during transients. The controller successfully dampens the resonant frequency of the filter and exhibits low grid-current harmonic distortion.

   Novel Software Defined Power Supply Utilizing Power Supply on Chip -Power supply which outputs the regulated output voltage by only connecting the load-
By Satoshi MATSUMOTO [View]
[Download]

Abstract: In this paper, we propose a novel software defined power supply using the general purpose DSP (Digital Signal Processor) and its control algorithm based on power supply on chip. The proposed power supply can regulate the output voltage only loading a program into the DSP without adjusting the parameters and changing the external parts. Also, it can change the output voltage according to the state of the load by executive instruction from the load. The simulation results show that the transient response depends on the inductance, the capacitance and the internal resistance, and expects sub-µ s. at switching frequency of 30 MHz.

   Selective harmonic suppression for finite-control-set model predictive control
By Martinus DORFLING [View]
[Download]

Abstract: For finite-control-set model predictive control with long horizons, a method is proposed that allows targeted harmonics in the current spectrum to be suppressed. The method involves adding band-pass filters at target frequencies, which are then included in the state-space representation of the prediction model. The underlying optimization problem can be efficiently solved with sphere decoding, allowing the use of long horizons to improve the system performance. A case study with a grid-connected converter is presented and simulations are provided that demonstrate the efficacy of the proposed method.

   Symmetry Relaxation of Three-Level Optimal Pulse Patterns for Lower Harmonic Distortion
By Annika BIRTH [View]
[Download]

Abstract: Pulse width modulation by optimized pulse patterns lowers the harmonic current distortions in high power converters as a result of a specifically designed optimization problem. The typically imposed quarter- and half-wave symmetry on the switching signal adds artificial restrictions to the optimization problem, which leads to suboptimal solutions. Relaxing these symmetry restrictions, a general optimization problem is formulated, which achieves up to 30\% lower harmonic distortions.

   Trade-off in Minimization of Fundamental Link Current and Reactive Power using a Novel Online Calculation based Triple Phase Shift Modulator for Dual Active Bri
By Srija MUKHERJEE [View]
[Download]

Abstract: The efficiency of the dual active bridge depends on amount of reactive power flows through the link and the RMS link current. This paper reports and analyses a trade-off study in minimization of reactive power and fundamental link current in dual active bridge converter using triple phase shift-based modulator. The conventional reactive power optimization method results in high zero portion in the link voltage and increases the peak of the link current and associated switch stresses. Firstly, an attempt is made to obtain the minimum link current and it results in increased reactive power exchange. Secondly, a novel modulator scheme based on online calculation is proposed to achieve desired trade-off between reactive power and fundamental current component in the transformer AC link. The detailed loss evaluation, analysis and experimental verification are presented in order to verify the proposed scheme.

   Two-Step Finite Control-Set Model Predictive Control for Three Phase UPS Inverters Feeding Non-linear loads
By Youssuf ELTHOKABY [View]
[Download]

Abstract: A two-step prediction horizon finite-control set model predictive control scheme is proposedfor three phase UPS inverters. Within the control scheme, a constraint is implemented to limit themaximum inverter inrush current, in case of non-linear loads, to an acceptable value. Simulation resultsshow that the proposed control scheme has been successful in limiting the inrush current and producinga load voltage with very low THD with small filter size.

   Voltage THD Reduction with Discontinuous Current Mode Control for Islanded-mode Operation in Single-phase Grid-tied Inverter
By Jun-ichi ITOH [View]
[Download]

Abstract: This paper proposes a filter capacitor design for a single-phase grid-tied inverter operating under islanded-mode with discontinuous current mode current control to reduce an inverter-side inductance and a filter capacitance without worsening output voltage distortion. The design considers the worst case of load, which is the non-linear load. A voltage source is applied to the circuit model of the load to obtain the harmonics of the current. By using these harmonics and the disturbance transfer function, the output voltage amplitude of the each harmonic components are obtained to calculate the output voltage total harmonic distortion (THD). Then, the filter capacitor satisfying the output voltage THD is determined by the theoretical output voltage THD calculation formula. The simulated output voltage THD agrees with the calculation value with the error of below 10\%. As experimental results with 1.5- kVA prototype, the output voltage THD with the CCM/DCM control method and the current feedforward is reduced by 88.8\% compared to that of the continuous current mode control method even with the minimized inductor impedance of 0.19\% and minimized capacitor admittance of 6.7\%.

EPE 2019 - DS2f: Standard and Advanced Control Techniques for Power Converters I
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 03: Measurement and Control > EPE 2019 - DS2f: Standard and Advanced Control Techniques for Power Converters I
	[return to parent folder]

	A Smooth Switching control method Based on a Variable-Structure Multi- Resonant DC-DC Converter By Mengying CHEN	[View] [Download]
Abstract: In this paper, based on a variable-structure multi-resonant DC-DC converter, a novel transient smoothcontrol method is proposed. Through the introduction of the gradual control idea, a drive signalgradual adjustment method is discussed. Consequently, smooth switching between different modes isrealized and the voltage fluctuation is suppressed effectively.

	Direct Multivariable Control of MMC Under Transient Conditions By Daniel DINKEL	[View] [Download]
Abstract: Modular Multilevel Converters (MMC) have become state of the art in many demanding application fields, because of several essential advantages. Main drivers of further progress are improved semiconductors (Si and SiC), advanced submodule topologies and new control schemes. Fully electronic fault management and reduced capacitor size and footprint of the converters are essential future requirements. These issues enforce new control concepts with very fast response under transient and fault conditions. An advanced multivariable control concept meeting these requirements is presented. Extensive simulation results of the transient behaviour are given.

	Full State Feedback Control of Buck-type PWM Rectifier By Lorenzo GIUNTINI	[View] [Download]
Abstract: Buck-type PWM rectifiers require an input LC filter, intrinsically exposed to resonance. Converter control needs to dominate the LC filter resonance. This paper details full state feedback controller design for the rectifier. Particularly, the paper demonstrates the equivalence of full state feedback control with PI controller plus active damping. Converter operation is validated experimentally on a 60 kVA rated rectifier.

	Gradient-Based Fixed Switching Frequency Direct Model Predictive Control for Grid-Connected Converters with LCL Filters By Mehrdad NAHALPARVARI	[View] [Download]
Abstract: This paper presents a direct model predictive control (MPC) scheme for a three-phase two-level grid-connected converter with an LCL filter. Despite the absence of a modulator, a fixed switching frequency and a discrete current harmonic spectrum are achieved. With a refined objective function of the optimization problem underlying MPC, grid current distortions comparable to those of carrier-based pulse width modulation (CB-PWM) in idealized conditions are produced. Moreover, the grid current harmonics meet the stringent limits imposed by grid standards. A performance evaluation is conducted to highlight the potential benefits of the proposed method.

	High Efficiency single-phase Dual-Active-Bridge AC/AC Converter By Raeed RAHMOUN	[View] [Download]
Abstract: This paper presents a 4 kVA single-phase isolated (230V/230V) ac/ac Dual Active Bridge (DAB)converter prototype suitable for Solid State Transformer (SST) applications. A solution for inductiveload is introduced and a novel control scheme based on gain scheduling approach is employed toimprove the DAB overall efficiency. Efficiency optimization is done based on global Zero-VoltageSwitching (ZVS) analysis of the DAB converter operating range for dual phase-shift modulation. Inthis analysis, minimization of both the Reactive Power per Switching Cycle (RPSC) and the rmscurrent of the high frequency inductance is taken into consideration to get the optimal modulationparameters. Simulation results are presented to validate the proposed control scheme.

	Impedance Modeling and Stability Analysis of Three-phase Grid-connected Inverter with LCL Filter in dq-frame By Yang HUA	[View] [Download]
Abstract: To study the system stability of three-phase grid-connected inverter with LCL filter, an impedance modeling method is established in this paper. This model built in the dq-frame considers the phase locked loop, the current control loop and what's more, the decoupling control method. Based on it, the output impedance model with active damping strategy is established. The accuracy of the model is verified by frequency scanning. After that, the Generalized Nyquist Criterion is applied to analyze the influence of controller parameters and the control strategy on the system stability. It is theoretically proved that decoupling control method can improve the system stability and the resonance peak can be restrained after adding active damping strategy. The validity of the model and the theoretical analysis are verified by simulations and experimental results, illustrating that the model proposed in this paper can be well used to analyze the three-phase LCL-type grid-connected inverter with decoupling control method and active damping strategy.

	Model Predictive Control with Space-Vector Modulation for a Grid-Connected Converter with an LCL-Filter By Adriaan SADIE	[View] [Download]
Abstract: This paper presents an indirect model predictive control (MPC) strategy with space-vector modulation (SVM). The controller is used to control a high-power voltage-source inverter (VSI), connected to the grid via an LCL-filter. The controller evaluates a multi-variable and convex cost function over a long prediction horizon in order to determine an optimal sequence of references for a space-vector modulator. The MPC strategy is tested in a Matlab simulation. The results of the simulation show excellent steady-state behaviour as well as a fast response during transients. The controller successfully dampens the resonant frequency of the filter and exhibits low grid-current harmonic distortion.

	Novel Software Defined Power Supply Utilizing Power Supply on Chip -Power supply which outputs the regulated output voltage by only connecting the load- By Satoshi MATSUMOTO	[View] [Download]
Abstract: In this paper, we propose a novel software defined power supply using the general purpose DSP (Digital Signal Processor) and its control algorithm based on power supply on chip. The proposed power supply can regulate the output voltage only loading a program into the DSP without adjusting the parameters and changing the external parts. Also, it can change the output voltage according to the state of the load by executive instruction from the load. The simulation results show that the transient response depends on the inductance, the capacitance and the internal resistance, and expects sub-µ s. at switching frequency of 30 MHz.

	Selective harmonic suppression for finite-control-set model predictive control By Martinus DORFLING	[View] [Download]
Abstract: For finite-control-set model predictive control with long horizons, a method is proposed that allows targeted harmonics in the current spectrum to be suppressed. The method involves adding band-pass filters at target frequencies, which are then included in the state-space representation of the prediction model. The underlying optimization problem can be efficiently solved with sphere decoding, allowing the use of long horizons to improve the system performance. A case study with a grid-connected converter is presented and simulations are provided that demonstrate the efficacy of the proposed method.

	Symmetry Relaxation of Three-Level Optimal Pulse Patterns for Lower Harmonic Distortion By Annika BIRTH	[View] [Download]
Abstract: Pulse width modulation by optimized pulse patterns lowers the harmonic current distortions in high power converters as a result of a specifically designed optimization problem. The typically imposed quarter- and half-wave symmetry on the switching signal adds artificial restrictions to the optimization problem, which leads to suboptimal solutions. Relaxing these symmetry restrictions, a general optimization problem is formulated, which achieves up to 30\% lower harmonic distortions.

	Trade-off in Minimization of Fundamental Link Current and Reactive Power using a Novel Online Calculation based Triple Phase Shift Modulator for Dual Active Bri By Srija MUKHERJEE	[View] [Download]
Abstract: The efficiency of the dual active bridge depends on amount of reactive power flows through the link and the RMS link current. This paper reports and analyses a trade-off study in minimization of reactive power and fundamental link current in dual active bridge converter using triple phase shift-based modulator. The conventional reactive power optimization method results in high zero portion in the link voltage and increases the peak of the link current and associated switch stresses. Firstly, an attempt is made to obtain the minimum link current and it results in increased reactive power exchange. Secondly, a novel modulator scheme based on online calculation is proposed to achieve desired trade-off between reactive power and fundamental current component in the transformer AC link. The detailed loss evaluation, analysis and experimental verification are presented in order to verify the proposed scheme.

	Two-Step Finite Control-Set Model Predictive Control for Three Phase UPS Inverters Feeding Non-linear loads By Youssuf ELTHOKABY	[View] [Download]
Abstract: A two-step prediction horizon finite-control set model predictive control scheme is proposedfor three phase UPS inverters. Within the control scheme, a constraint is implemented to limit themaximum inverter inrush current, in case of non-linear loads, to an acceptable value. Simulation resultsshow that the proposed control scheme has been successful in limiting the inrush current and producinga load voltage with very low THD with small filter size.

	Voltage THD Reduction with Discontinuous Current Mode Control for Islanded-mode Operation in Single-phase Grid-tied Inverter By Jun-ichi ITOH	[View] [Download]
Abstract: This paper proposes a filter capacitor design for a single-phase grid-tied inverter operating under islanded-mode with discontinuous current mode current control to reduce an inverter-side inductance and a filter capacitance without worsening output voltage distortion. The design considers the worst case of load, which is the non-linear load. A voltage source is applied to the circuit model of the load to obtain the harmonics of the current. By using these harmonics and the disturbance transfer function, the output voltage amplitude of the each harmonic components are obtained to calculate the output voltage total harmonic distortion (THD). Then, the filter capacitor satisfying the output voltage THD is determined by the theoretical output voltage THD calculation formula. The simulated output voltage THD agrees with the calculation value with the error of below 10\%. As experimental results with 1.5- kVA prototype, the output voltage THD with the CCM/DCM control method and the current feedforward is reduced by 88.8\% compared to that of the continuous current mode control method even with the minimized inductor impedance of 0.19\% and minimized capacitor admittance of 6.7\%.