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http://hdl.handle.net/10985/13594
Torque optimization of seven phase BLDC machines in normal and degraded modes with constraints on current and voltage
VU, Duc Tan; NGUYEN, Ngac Ky; SEMAIL, Eric; DOS SANTOS MORAES, Tiago José
This paper proposes several easy-to-implement control strategies when seven-phase axial flux brushless DC machines with trapezoidal back electromotive forces operate in normal and faulty modes by taking into account constraints on voltage and current. The constraints are related to the converter and machine design in terms of maximum values of current and voltage. The considered faults are cases in which one or two phases of the machine are open-circuited. Numerical computations based on analytical formulations are applied to obtain torque-speed characteristics, including the fluxweakening operation. The methods determine current references to ensure the torque optimizations while currents and voltages are within their limits. The usefulness of the methods is verified by numerical results.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/135942018-01-01T00:00:00ZVU, Duc TanNGUYEN, Ngac KySEMAIL, EricDOS SANTOS MORAES, Tiago JoséThis paper proposes several easy-to-implement control strategies when seven-phase axial flux brushless DC machines with trapezoidal back electromotive forces operate in normal and faulty modes by taking into account constraints on voltage and current. The constraints are related to the converter and machine design in terms of maximum values of current and voltage. The considered faults are cases in which one or two phases of the machine are open-circuited. Numerical computations based on analytical formulations are applied to obtain torque-speed characteristics, including the fluxweakening operation. The methods determine current references to ensure the torque optimizations while currents and voltages are within their limits. The usefulness of the methods is verified by numerical results.Sensitivity of Torque Control for Seven-phase BLDC Machine with One Opened Phase under Constraints on Voltage and Current
http://hdl.handle.net/10985/13807
Sensitivity of Torque Control for Seven-phase BLDC Machine with One Opened Phase under Constraints on Voltage and Current
VU, Duc Tan; NGUYEN, Ngac Ky; SEMAIL, Eric
This paper deals with control strategies when a sevenphase axial-flux brushless DC machine operates in one opencircuited phase fault by considering constraints on voltage and current. The constraints are related to the converter and machine design in terms of peak values of non-sinusoidal voltage and current. In addition, the sensitivity of the torque control on parameters of new imposed current references under the base speed and in the flux-weakening region is analyzed. The current references taking into account only first and third harmonics in healthy phases are proposed to ensure the torque optimization while phase currents and voltages are within their limits. The usefulness of the control strategies and the parameter analyses are verified by numerical results.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/138072018-01-01T00:00:00ZVU, Duc TanNGUYEN, Ngac KySEMAIL, EricThis paper deals with control strategies when a sevenphase axial-flux brushless DC machine operates in one opencircuited phase fault by considering constraints on voltage and current. The constraints are related to the converter and machine design in terms of peak values of non-sinusoidal voltage and current. In addition, the sensitivity of the torque control on parameters of new imposed current references under the base speed and in the flux-weakening region is analyzed. The current references taking into account only first and third harmonics in healthy phases are proposed to ensure the torque optimization while phase currents and voltages are within their limits. The usefulness of the control strategies and the parameter analyses are verified by numerical results.Control Strategies for Non-sinusoidal Multiphase PMSM Drives in Faulty Modes under Constraints on Copper Losses and Peak Phase Voltage
http://hdl.handle.net/10985/15157
Control Strategies for Non-sinusoidal Multiphase PMSM Drives in Faulty Modes under Constraints on Copper Losses and Peak Phase Voltage
VU, Duc Tan; NGUYEN, Ngac Ky; SEMAIL, Eric; DOS SANTOS MORAES, Tiago Jose
In the context of future Permanent Magnet Synchronous Machines (PMSMs) with a high number of phases (>7) in integrated drives, this paper proposes several control strategies when multiphase PMSMs with non-sinusoidal back electromotive forces (back-EMFs) operate in healthy and open-circuit faults. In all operation modes, the considered constraint on current is related to the maximum root mean square (RMS) current allowable in one phase of the machine. The constraint on voltage limits the maximum peak value of the phase voltage determined by the DC-bus voltage of the converter. When one or two phases are open-circuited, to maximize torque and respect the constraints, new current references obtained by several proposed methods in rotating and natural frames are imposed to the machine. Due to the non-sinusoidal waveform of back-EMFs and the considered constraints, numerical computations based on analytical formulations are required to obtain maximal torque-speed characteristics, including the flux-weakening operation. The usefulness of the proposed strategies is verified by numerical and experimental results.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/151572019-01-01T00:00:00ZVU, Duc TanNGUYEN, Ngac KySEMAIL, EricDOS SANTOS MORAES, Tiago JoseIn the context of future Permanent Magnet Synchronous Machines (PMSMs) with a high number of phases (>7) in integrated drives, this paper proposes several control strategies when multiphase PMSMs with non-sinusoidal back electromotive forces (back-EMFs) operate in healthy and open-circuit faults. In all operation modes, the considered constraint on current is related to the maximum root mean square (RMS) current allowable in one phase of the machine. The constraint on voltage limits the maximum peak value of the phase voltage determined by the DC-bus voltage of the converter. When one or two phases are open-circuited, to maximize torque and respect the constraints, new current references obtained by several proposed methods in rotating and natural frames are imposed to the machine. Due to the non-sinusoidal waveform of back-EMFs and the considered constraints, numerical computations based on analytical formulations are required to obtain maximal torque-speed characteristics, including the flux-weakening operation. The usefulness of the proposed strategies is verified by numerical and experimental results.Electric Vehicles Driven by 5-phase Open-End Winding Machines Fed by Battery and Supercapacitors
http://hdl.handle.net/10985/17209
Electric Vehicles Driven by 5-phase Open-End Winding Machines Fed by Battery and Supercapacitors
VU, Duc Tan; NGUYEN, Ngac Ky; SEMAIL, Eric; LHOMME, Walter
This paper presents the modeling and control of an Electric Vehicle (EV) driven by a 5-phase Permanent Magnet Synchronous Machine (PMSM). The machine in an open-end winding configuration is supplied by two isolated 5-leg Voltage Source Inverters (VSIs). The inverters are fed by a Hybrid Energy Storage System (HESS) consisting of a battery and Supercapacitors (SCs). To increase the battery lifetime, the SCs are used to provide the high-power requirement during driving operations. In addition, an Energy Management Strategy (EMS) is proposed to take advantages of this EV architecture. Numerical results are derived to verify workability of the EV system.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/172092019-01-01T00:00:00ZVU, Duc TanNGUYEN, Ngac KySEMAIL, EricLHOMME, WalterThis paper presents the modeling and control of an Electric Vehicle (EV) driven by a 5-phase Permanent Magnet Synchronous Machine (PMSM). The machine in an open-end winding configuration is supplied by two isolated 5-leg Voltage Source Inverters (VSIs). The inverters are fed by a Hybrid Energy Storage System (HESS) consisting of a battery and Supercapacitors (SCs). To increase the battery lifetime, the SCs are used to provide the high-power requirement during driving operations. In addition, an Energy Management Strategy (EMS) is proposed to take advantages of this EV architecture. Numerical results are derived to verify workability of the EV system.Fault-tolerant Control for 7-phase Non-sinusoidal Permanent Magnet Machines with One Opened Phase
http://hdl.handle.net/10985/17208
Fault-tolerant Control for 7-phase Non-sinusoidal Permanent Magnet Machines with One Opened Phase
YANAGIHARA, Keitaro; VU, Duc Tan; NGUYEN, Ngac Ky; GONG, Jinlin; SEMAIL, Eric; DOS SANTOS MORAES, Tiago José
This paper presents new fault-tolerant control strategies for field-oriented control of 7-phase non-sinusoidal permanent magnet (PM) machines supplied by voltage source inverters (VSI). Single phase open-circuit fault is considered. The proposed strategies aim at finding waveforms of current references in natural frame in the way that post-fault currents create the same rotational magnetomotive force (MMF) as in healthy mode. Therefore, in the faulty mode, average torque can be maintained if no current limits are set. The proposed strategies are validated and compared to a previous strategy by numerical results in terms of joule losses, maximum RMS and peak phase currents, maximum phase voltage as well as their controllability with PI controllers.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/172082019-01-01T00:00:00ZYANAGIHARA, KeitaroVU, Duc TanNGUYEN, Ngac KyGONG, JinlinSEMAIL, EricDOS SANTOS MORAES, Tiago JoséThis paper presents new fault-tolerant control strategies for field-oriented control of 7-phase non-sinusoidal permanent magnet (PM) machines supplied by voltage source inverters (VSI). Single phase open-circuit fault is considered. The proposed strategies aim at finding waveforms of current references in natural frame in the way that post-fault currents create the same rotational magnetomotive force (MMF) as in healthy mode. Therefore, in the faulty mode, average torque can be maintained if no current limits are set. The proposed strategies are validated and compared to a previous strategy by numerical results in terms of joule losses, maximum RMS and peak phase currents, maximum phase voltage as well as their controllability with PI controllers.An Overview of Methods using Reduced-Ordered Transformation Matrices for Fault-Tolerant Control of 5-phase Machines with an Open Phase
http://hdl.handle.net/10985/15118
An Overview of Methods using Reduced-Ordered Transformation Matrices for Fault-Tolerant Control of 5-phase Machines with an Open Phase
VU, Duc Tan; NGUYEN, Ngac Ky; SEMAIL, Eric
This paper studies control strategies using modified transformation matrices when five-phase machines operate in oneopen-phase faults. The basic idea of these methods is to maintain the rotating field under asymmetrical conditions as the same as in healthy condition by determining new transformation matrices. The dimension of the new matrices is equal to the number of remaining healthy phases in post-fault conditions. There have been different ways to determine the new transformation matrices applied for different types of five-phase machines in recent decades. In this study, an overview and analyses on these methods will be presented. In addition, advantages and drawbacks of these control strategies are clarified by numerical results.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/151182019-01-01T00:00:00ZVU, Duc TanNGUYEN, Ngac KySEMAIL, EricThis paper studies control strategies using modified transformation matrices when five-phase machines operate in oneopen-phase faults. The basic idea of these methods is to maintain the rotating field under asymmetrical conditions as the same as in healthy condition by determining new transformation matrices. The dimension of the new matrices is equal to the number of remaining healthy phases in post-fault conditions. There have been different ways to determine the new transformation matrices applied for different types of five-phase machines in recent decades. In this study, an overview and analyses on these methods will be presented. In addition, advantages and drawbacks of these control strategies are clarified by numerical results.Torque Optimization of a Seven-Phase Bi-harmonic PMSM in Healthy and Degraded Mode
http://hdl.handle.net/10985/16155
Torque Optimization of a Seven-Phase Bi-harmonic PMSM in Healthy and Degraded Mode
ZHANG, Hao; ZHAO, Benteng; GONG, Jinlin; XU, Yanliang; VU, Duc Tan; NGUYEN, Ngac Ky; SEMAIL, Eric; DOS SANTOS MORAES, Tiago José
Compared to sinusoidal machines, a bi-harmonic machine (with only two harmonics of similar value in the electromotive force spectrum) can develop torque of comparable values under three kinds of supply: with only first or both first and third sinusoidal currents. Therefore, more degrees of freedom for the control of the machine can be achieved. In this paper, the specificities of a 7-phase bi-harmonic permanent magnet synchronous machine (PMSM) are investigated under different control strategies, such as maximum torque per ampere (MTPA) at low speed and fluxweakening strategies at high speed, both in healthy and faulty operation modes. The fault with one open-circuited phase are taken into account. The current references are calculated in order to maximize the output torque under the constraint on both voltage and current. The performances of the considered machine is validated by numerical results.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/161552019-01-01T00:00:00ZZHANG, HaoZHAO, BentengGONG, JinlinXU, YanliangVU, Duc TanNGUYEN, Ngac KySEMAIL, EricDOS SANTOS MORAES, Tiago JoséCompared to sinusoidal machines, a bi-harmonic machine (with only two harmonics of similar value in the electromotive force spectrum) can develop torque of comparable values under three kinds of supply: with only first or both first and third sinusoidal currents. Therefore, more degrees of freedom for the control of the machine can be achieved. In this paper, the specificities of a 7-phase bi-harmonic permanent magnet synchronous machine (PMSM) are investigated under different control strategies, such as maximum torque per ampere (MTPA) at low speed and fluxweakening strategies at high speed, both in healthy and faulty operation modes. The fault with one open-circuited phase are taken into account. The current references are calculated in order to maximize the output torque under the constraint on both voltage and current. The performances of the considered machine is validated by numerical results.Optimal torque/speed characteristics of a Five-Phase Synchronous Machine under Peak or RMS current control strategies
http://hdl.handle.net/10985/19515
Optimal torque/speed characteristics of a Five-Phase Synchronous Machine under Peak or RMS current control strategies
DOS SANTOS MORAES, Tiago Jose; WU, Hailong; SEMAIL, Eric; NGUYEN, Ngac Ky; VU, Duc Tan
Torque density is usually improved by injecting the third current harmonic for five-phase permanent magnet synchronous machine (PMSM). It increases the degrees of freedom of a multiphase drive. However, it also separates the current limitations of the motor and the transistors, respectively related to the RMS and peak values of the currents. These two constraints are represented by Maximum Torque Per Ampere (MTPA) strategy and Maximum Torque Per Peak Current (MTPPC) strategy. In this paper, these two strategies are studied and analyzed in order to optimize the generated torque with injection of the third current harmonic. Torque improvement principle and the optimizing algorithm considering two constraints are illustrated. Then, the analytical results of these two strategies are compared and discussed. It is shown that injecting the third current harmonic can improve the torque especially at flux-weakening region. Besides, compared with MTPA, MTPPC could produce higher torque for the same inverter current limit.
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/10985/195152020-01-01T00:00:00ZDOS SANTOS MORAES, Tiago JoseWU, HailongSEMAIL, EricNGUYEN, Ngac KyVU, Duc TanTorque density is usually improved by injecting the third current harmonic for five-phase permanent magnet synchronous machine (PMSM). It increases the degrees of freedom of a multiphase drive. However, it also separates the current limitations of the motor and the transistors, respectively related to the RMS and peak values of the currents. These two constraints are represented by Maximum Torque Per Ampere (MTPA) strategy and Maximum Torque Per Peak Current (MTPPC) strategy. In this paper, these two strategies are studied and analyzed in order to optimize the generated torque with injection of the third current harmonic. Torque improvement principle and the optimizing algorithm considering two constraints are illustrated. Then, the analytical results of these two strategies are compared and discussed. It is shown that injecting the third current harmonic can improve the torque especially at flux-weakening region. Besides, compared with MTPA, MTPPC could produce higher torque for the same inverter current limit.Eliminations of Low-frequency Current Harmonics for Five-phase Open-end Winding Non-sinusoidal Machine Drives applying Neural Networks
http://hdl.handle.net/10985/19555
Eliminations of Low-frequency Current Harmonics for Five-phase Open-end Winding Non-sinusoidal Machine Drives applying Neural Networks
VU, Duc Tan; NGUYEN, Ngac Ky; SEMAIL, Eric
This study aims at eliminating unwanted harmonics in current control of a five-phase non-sinusoidal permanent magnet synchronous machine (PMSM) in an open-end winding configuration. The machine is supplied by two voltage source inverters (VSIs) using a single DC-bus voltage. High-frequency harmonics, caused by the zero-sequence current with the inverter switching frequency, have been significantly reduced by using a proper pulse width modulation (PWM) strategy. Meanwhile, low-frequency current harmonics are generated by unwanted harmonics of the back electromotive force (back-EMF) and by the inverter nonlinearity. In this study, the low-frequency current harmonics are nullified by simple adaptive linear neural networks (ADALINEs) in rotor reference frames combined with the back-EMF compensation. As a result, the quality of current control is improved. The effectiveness of the proposed strategies is verified by numerical results
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/10985/195552020-01-01T00:00:00ZVU, Duc TanNGUYEN, Ngac KySEMAIL, EricThis study aims at eliminating unwanted harmonics in current control of a five-phase non-sinusoidal permanent magnet synchronous machine (PMSM) in an open-end winding configuration. The machine is supplied by two voltage source inverters (VSIs) using a single DC-bus voltage. High-frequency harmonics, caused by the zero-sequence current with the inverter switching frequency, have been significantly reduced by using a proper pulse width modulation (PWM) strategy. Meanwhile, low-frequency current harmonics are generated by unwanted harmonics of the back electromotive force (back-EMF) and by the inverter nonlinearity. In this study, the low-frequency current harmonics are nullified by simple adaptive linear neural networks (ADALINEs) in rotor reference frames combined with the back-EMF compensation. As a result, the quality of current control is improved. The effectiveness of the proposed strategies is verified by numerical resultsCurrent Harmonic Eliminations for Seven-Phase Non-sinusoidal PMSM Drives applying Artificial Neurons
http://hdl.handle.net/10985/19666
Current Harmonic Eliminations for Seven-Phase Non-sinusoidal PMSM Drives applying Artificial Neurons
VU, Duc Tan; NGUYEN, Ngac-Ky; SEMAIL, Eric; NGUYEN, Thi Thanh Nga
This study is to deal with unwanted current harmonics in rotating (d-q) frames of a 7-phase non-sinusoidal permanent magnet synchronous machine (PMSM) in a wye-connected winding topology. The machine is supplied by a 7-leg voltage source inverter (VSI) fed by a DC-bus voltage. In control, current responses are expected to properly track their references. However, several unwanted harmonics of the non-sinusoidal back electromotive force (back-EMF) and the inverter nonlinearity generate unwanted harmonic components in d-q currents. These current harmonics cannot be nullified by controllers such as conventional proportional-integral (PI) controllers. Consequently, the current responses cannot track their references. In this study, a combination of conventional PI controllers and simple adaptive linear neurons (ADALINEs) is proposed to eliminate these current harmonics, improving current control quality of the drive. The effectiveness of the proposed control structure is verified by experimental results.
Wed, 01 Jan 2020 00:00:00 GMThttp://hdl.handle.net/10985/196662020-01-01T00:00:00ZVU, Duc TanNGUYEN, Ngac-KySEMAIL, EricNGUYEN, Thi Thanh NgaThis study is to deal with unwanted current harmonics in rotating (d-q) frames of a 7-phase non-sinusoidal permanent magnet synchronous machine (PMSM) in a wye-connected winding topology. The machine is supplied by a 7-leg voltage source inverter (VSI) fed by a DC-bus voltage. In control, current responses are expected to properly track their references. However, several unwanted harmonics of the non-sinusoidal back electromotive force (back-EMF) and the inverter nonlinearity generate unwanted harmonic components in d-q currents. These current harmonics cannot be nullified by controllers such as conventional proportional-integral (PI) controllers. Consequently, the current responses cannot track their references. In this study, a combination of conventional PI controllers and simple adaptive linear neurons (ADALINEs) is proposed to eliminate these current harmonics, improving current control quality of the drive. The effectiveness of the proposed control structure is verified by experimental results.