EPE Association: EPE 2021 - Design and Control of Electric Drives

EPE 2021 - Design and Control of Electric Drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2021 ECCE Europe - Conference > EPE 2021 - Topic 05: Renewable Energy Power Systems > EPE 2021 - Design and Control of Electric Drives

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   An Assessment of Finite Control Set Predictive Current Control with Concept of Variable Switching Point or Parallel Cost Function for Induction Motor
By Qing CHEN [View]
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Abstract: This paper presents an assessment of finite-control-set predictive current control with concept of variable switchingpoint or parallel cost function for induction motor. Based on the concept of variable switching point or parallel costfunction, variable switching point predictive current control (VSP2CC), parallel predictive current control (PPCC),and variable switching point parallel predictive current control (VSP3CC) were proposed by different researchersto tackle the drawbacks of traditional PCC strategy. Simulation results and experimental results are provided tooffer a detailed comparison among these four different current control strategies for an induction motor.

   Functional Safety Torque Estimation Methods for Position Sensorless Control applied to Synchronous Machines in Electric Vehicles
By Julius ROGOWSKY [View]
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Abstract: For the use of position sensorless control in automotive traction drives, the standard functional safetyconcept of power inverter modules is not applicable due to omission of the rotor position sensor. To overcome this issue, a modified functional safety concept is proposed. In this context, torque estimation methods known from literature based on flux tables and power comparison are compared by sensitivity analysis with a new developed method based on magnitude of stator current and flux to ensure reliable torque monitoring over complete operating area without using the rotor position information. While methods based on stator flux and power comparison only show adequate accuracy at mid and high motor speed, the new developed method fills the gap down to zero motor speed. This results in a combination of three methods for an optimized strategy depending on the motor speed. Measurements on a series production electric machine verify the proposed approach and gives, from a functional safety perspective, the possibility to omit rotor position sensor in automotive traction drives.

   Optimal open loop control for a fast transition from normal to active-short-circuit operation
By Philipp WAGNER [View]
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Abstract: A novel approach for a fast transition to the safe state i.e. active-short-circuit (ASC) based on optimalcontrol prevents the dc-link voltage and the phase currents from exceeding critical limits. Before switching to the ASC, the novel approach controls the permanent-magnet synchronous machine (PSM) to the steady-state short-circuit operational point by assuming the inverter and PSM are still functioning. To design an optimal control pattern, two optimization problem formulations are useful. By finding the dc-link optimal voltage pattern, a critical dc-link voltage overshoot can be minimized. A simplified time-optimal dq-voltage pattern can be used if the dc-link voltage does not have to be taken into account. Simulation results as well as experimental results demonstrate the new approach both in base-speed and field-weakening-area; and compare it to conventional methods like Hard-ASC and Soft-ASC.

   Torque Ripple Suppression Method based on FOC for SRM without FEM Analysis
By Kouki TOKUI [View]
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Abstract: This paper proposes a torque ripple suppression method for a switched reluctance motor (SRM) with only measurable parameters. A large third-order torque ripple is generated by a conventional method with constant dq0-axis current, which is dq-axis current and zero-phase current converted from the three phase current of SRM. Moreover, the conventional method assumes an inductance profile constant regarding a change in the current. In the magnetic saturation region, the inductance decreases at an aligned position. Thus, an effect of the torque ripple suppression method becomes low and the average torque cannot be controlled in the magnetic saturation region. The proposed method derives the zero-phase current with the third-order harmonic in order to suppress the torque ripple from a torque equation considering spatial harmonics of the inductance profile up to the forth order and torque/current ratio in whole region. In addition, an average torque control is proposed for the magnetic saturation region. The average torque equation is derived from the inductance expressing the magnetic co-energy at the magnetic saturation. As a result, the experiments demonstrated that the torque ripple is reduced by 76.1\% in the linear region and by 73.4\% in the magnetic saturation region compared to the conventional method with the constant dq0-axis current. Moreover, the derived average torque equation agrees with the experimental results including the error of 3.9\%.

EPE 2021 - Design and Control of Electric Drives
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2021 ECCE Europe - Conference > EPE 2021 - Topic 05: Renewable Energy Power Systems > EPE 2021 - Design and Control of Electric Drives
	[return to parent folder]

	An Assessment of Finite Control Set Predictive Current Control with Concept of Variable Switching Point or Parallel Cost Function for Induction Motor By Qing CHEN	[View] [Download]
Abstract: This paper presents an assessment of finite-control-set predictive current control with concept of variable switchingpoint or parallel cost function for induction motor. Based on the concept of variable switching point or parallel costfunction, variable switching point predictive current control (VSP2CC), parallel predictive current control (PPCC),and variable switching point parallel predictive current control (VSP3CC) were proposed by different researchersto tackle the drawbacks of traditional PCC strategy. Simulation results and experimental results are provided tooffer a detailed comparison among these four different current control strategies for an induction motor.

	Functional Safety Torque Estimation Methods for Position Sensorless Control applied to Synchronous Machines in Electric Vehicles By Julius ROGOWSKY	[View] [Download]
Abstract: For the use of position sensorless control in automotive traction drives, the standard functional safetyconcept of power inverter modules is not applicable due to omission of the rotor position sensor. To overcome this issue, a modified functional safety concept is proposed. In this context, torque estimation methods known from literature based on flux tables and power comparison are compared by sensitivity analysis with a new developed method based on magnitude of stator current and flux to ensure reliable torque monitoring over complete operating area without using the rotor position information. While methods based on stator flux and power comparison only show adequate accuracy at mid and high motor speed, the new developed method fills the gap down to zero motor speed. This results in a combination of three methods for an optimized strategy depending on the motor speed. Measurements on a series production electric machine verify the proposed approach and gives, from a functional safety perspective, the possibility to omit rotor position sensor in automotive traction drives.

	Optimal open loop control for a fast transition from normal to active-short-circuit operation By Philipp WAGNER	[View] [Download]
Abstract: A novel approach for a fast transition to the safe state i.e. active-short-circuit (ASC) based on optimalcontrol prevents the dc-link voltage and the phase currents from exceeding critical limits. Before switching to the ASC, the novel approach controls the permanent-magnet synchronous machine (PSM) to the steady-state short-circuit operational point by assuming the inverter and PSM are still functioning. To design an optimal control pattern, two optimization problem formulations are useful. By finding the dc-link optimal voltage pattern, a critical dc-link voltage overshoot can be minimized. A simplified time-optimal dq-voltage pattern can be used if the dc-link voltage does not have to be taken into account. Simulation results as well as experimental results demonstrate the new approach both in base-speed and field-weakening-area; and compare it to conventional methods like Hard-ASC and Soft-ASC.

	Torque Ripple Suppression Method based on FOC for SRM without FEM Analysis By Kouki TOKUI	[View] [Download]
Abstract: This paper proposes a torque ripple suppression method for a switched reluctance motor (SRM) with only measurable parameters. A large third-order torque ripple is generated by a conventional method with constant dq0-axis current, which is dq-axis current and zero-phase current converted from the three phase current of SRM. Moreover, the conventional method assumes an inductance profile constant regarding a change in the current. In the magnetic saturation region, the inductance decreases at an aligned position. Thus, an effect of the torque ripple suppression method becomes low and the average torque cannot be controlled in the magnetic saturation region. The proposed method derives the zero-phase current with the third-order harmonic in order to suppress the torque ripple from a torque equation considering spatial harmonics of the inductance profile up to the forth order and torque/current ratio in whole region. In addition, an average torque control is proposed for the magnetic saturation region. The average torque equation is derived from the inductance expressing the magnetic co-energy at the magnetic saturation. As a result, the experiments demonstrated that the torque ripple is reduced by 76.1\% in the linear region and by 73.4\% in the magnetic saturation region compared to the conventional method with the constant dq0-axis current. Moreover, the derived average torque equation agrees with the experimental results including the error of 3.9\%.