AbstractTraditional high-frequency pulse width modulation (PWM) inverters for motor drives have ... more AbstractTraditional high-frequency pulse width modulation (PWM) inverters for motor drives have several problems associated with their high frequency switching which produces high voltage change (dV/dt) rates. Multilevel inverters solve these problems because their devices switch at the fundamental frequency. Two different multilevel topologies are identified for use as a converter for electric drives, a cascade inverter with separate dc sources and a back-to-back diode clamped converter. The cascade inverter is a natural fit for large automotive electric drives because of the high VA ratings possible and because it uses several levels of dc voltage sources which would be available from batteries or fuel cells. The back-to-back diode clamped converter is ideal for use where a generator or alterntator produces ac voltage. Simulation and experimental results show the superiority of these two converters over PWM based drives.
Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings a... more Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings are being investigated as candidates for high-performance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constant-power speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque
Proceedings of PESC '95 - Power Electronics Specialist Conference, 1995
In this paper, a multilevel voltage-source converter system is proposed for high-voltage, high-po... more In this paper, a multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as back-to-back interconnection of power systems, large induction motor drives, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the DC capacitors. The problem may be solved by use of additional voltage regulators or separate DC sources. However, these solutions are
... Downing, Mark [ORNL] ; Stahlhut, Ronnie D [ORNL] ; Bremmer, R. [John Deere -- Moline Tech Cen... more ... Downing, Mark [ORNL] ; Stahlhut, Ronnie D [ORNL] ; Bremmer, R. [John Deere -- Moline Tech Center] ; Shoemaker, JM [John Deere -- Moline Tech Center] ; Seksarian, AK [John Deere -- Moline Tech Center] ; Poore, B. [John Deere -- Moline Tech Center] ; Lutz, Jon F [ORNL]. ...
Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings a... more Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings are being investigated as candidates for high-performance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constant-power speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque
The reluctance interior permanent magnet (RIPM) motor is currently used by many leading auto manu... more The reluctance interior permanent magnet (RIPM) motor is currently used by many leading auto manufacturers for hybrid vehicles. The power density for this type of motor is high compared with that of induction motors and switched reluctance motors. The primary drawback of the RIPM motor is the permanent magnet (PM) because during high-speed operation, the fixed PM produces a huge back electromotive force (emf) that must be reduced before the current will pass through the stator windings. This reduction in back-emf is accomplished with a significant direct-axis (d-axis) demagnetization current, which opposes the PM's flux to reduce the flux seen by the stator wires. This may lower the power factor and efficiency of the motor and raise the requirement on the alternate current (ac) power supply; consequently, bigger inverter switching components, thicker motor winding conductors, and heavier cables are required. The direct current (dc) link capacitor is also affected when it must accommodate heavier harmonic currents. It is commonly agreed that, for synchronous machines, the power factor can be optimized by varying the field excitation to minimize the current. The field produced by the PM is fixed and cannot be adjusted. What can be adjusted is reactive current to the d-axis of the stator winding, which consumes reactive power but does not always help to improve the power factor. The objective of this project is to avoid the primary drawbacks of the RIPM motor by introducing brushless field excitation (BFE). This offers both high torque per ampere (A) per core length at low speed by using flux, which is enhanced by increasing current to a fixed excitation coil, and flux, which is weakened at high speed by reducing current to the excitation coil. If field weakening is used, the dc/dc boost converter used in a conventional RIPM motor may be eliminated to reduce system costs. However, BFE supports a drive system with a dc/dc boost converter, because it can further extend the constant power speed range of the drive system and adjust the field for power factor and efficiency gains. Lower core losses at low torque regions, especially at high speeds, are attained by reducing the field excitation. Safety and reliability are increased by weakening the field when a winding short-circuit fault occurs, preventing damage to the motor. For a high-speed motor operating at 16,000-revolutions per minute (rpm), mechanical stress is a challenge. Bridges that link the rotor punching segments together must be thickened for mechanical integrity; consequently, increased rotor flux leakage significantly lowers motor performance. This barrier can be overcome by BFE to ensure sufficient rotor flux when needed.
A 30 pole, 6 kW, and 6000 maximum revolutions per minute (rpm) prototype of the permanent magnet ... more A 30 pole, 6 kW, and 6000 maximum revolutions per minute (rpm) prototype of the permanent magnet synchronous motor (PMSM) with fractional-slot concentrated windings (FSCW) has been designed, built, and tested at the University of Wisconsin at Madison (UWM). This ...
... Kelly S. Samons, Roy L. Kessinger Visual Computing System ... Soc. Ann. Mtg., pp. 1339-1345. ... more ... Kelly S. Samons, Roy L. Kessinger Visual Computing System ... Soc. Ann. Mtg., pp. 1339-1345. 2. M. Lajoie-Mazenc, C. Villanueva, J. Hector, Study and Implementation of Hysteresis Controlled Inverter on a Permanent Magnet Synchronous Machine, Conf. Rec. 1984 IEEE Ind. ...
IECON'01. 27th Annual Conference of the IEEE Industrial Electronics Society (Cat. No.37243), 2001
This paper presents modular permanent magnet (PM) motor drives for automotive traction applicatio... more This paper presents modular permanent magnet (PM) motor drives for automotive traction applications. A partially modularized drive system consisting of a single PM motor and multiple inverters is described. The motor has multiple three-phase stator winding sets and each winding set is driven with a separate three-phase inverter module. A truly modularized inverter and motor configuration based on an axial-gap PM motor is then introduced, in which identical PM motor modules are mounted on a common shaft and each motor module is powered by a separate inverter module. The advantages of the modular approach for both inverter and motor include: 1) power rating scalability -one design meets different power requirements by simply stacking an adequate number of modules, thus avoiding redesigning and reducing the development cost, 2) increased fault tolerance, and 3) easy repairing. A prototype was constructed by using two inverters and an axial-gap PM motor with two sets of three-phase stator windings, and it is used to assist the diesel engine in a hybrid electric vehicle converted from a Chevrolet Suburban. The effect of different pulse-width-modulation strategies for both motoring and regenerative modes on current control is analyzed. Torque and regenerative control algorithms are implemented with a digital signal processor. Analytical and initial testing results are included in the paper.
An inverter topology and control scheme has been developed that can drive low-inductance, surface... more An inverter topology and control scheme has been developed that can drive low-inductance, surface-mounted permanent magnet motors over the wide constant power speed range required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC) [1]. The DMIC can drive either the Permanent Magnet Synchronous Machine (PMSM) with sinusoidal back emf, or the brushless dc machine (BDCM) with trapezoidal emf in the motoring and regenerative braking modes. In this paper we concentrate on the BDCM under high-speed motoring conditions. Simulation results show that if all motor and inverter loss mechanisms are neglected, the constant power speed range of the DMIC is infinite. The simulation results are supported by closed form expressions for peak and rms motor current and average power derived from analytical solution to the differential equations governing the DMIC/BDCM drive for the lossless case. The analytical solution shows that the range of motor in...
The differential equations that describe the operation of the brushless dc motor (BDCM) driven by... more The differential equations that describe the operation of the brushless dc motor (BDCM) driven by dual mode inverter control (DMIC) are solved analytically. Explicit expressions for peak and rms motor current and average motor power are derived. The analysis is performed neglecting all motor loss mechanisms. The results provide a theoretical verification that the constant power speed range (CPSR) of the BDCM is infinite when driven by the DMIC. While speed sensitive motor losses limit the CPSR of any practical drive to a finite value, there is no inherent limitation imposed by the DMIC. The analytic formulas provide useful drive design guidance without requiring simulation or laboratory experimentation.
A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc... more A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.
The exact analytical formulas for radial action of the Kratzer and Davidson rotating vibrators an... more The exact analytical formulas for radial action of the Kratzer and Davidson rotating vibrators and the WKB approximation for the radial action of Dunham's one-dimensional rotating vibrator have indicated that the form of the action is Ir = h[v+1/2+ε{J(J+1)}] The correctness of this form was verified through use in the Rydberg-Klein method which was analytically applied to energy eigenvalue formulas
Previous theoretical work has shown that when all loss mechanisms are neglected the constant powe... more Previous theoretical work has shown that when all loss mechanisms are neglected the constant power speed range (CPSR) of a brushless dc motor (BDCM) is infinite when the motor is driven by the dual-mode inverter control (DMIC) (1,2). In a physical drive, losses, particularly speed-sensitive losses, will limit the CPSR to a finite value. In this paper we report the results of laboratory testing of a low-inductance, 7.5-hp BDCM driven by the DMIC. The speed rating of the test motor rotor limited the upper speed of the testing, and the results show that the CPSR of the test machine is greater than 6:1 when driven by the DMIC. Current wave shape, peak, and rms values remained controlled and within rating over the entire speed range. The laboratory measurements allowed the speed-sensitive losses to be quantified and incorporated into computer simulation models, which then accurately reproduce the results of lab testing. The simulator shows that the limiting CPSR of the test motor is 8:1....
An inverter topology and control scheme has been developed and tested to demonstrate that it can ... more An inverter topology and control scheme has been developed and tested to demonstrate that it can drive low-inductance, surface mounted permanent magnet motors over the wide constant power speed range (CPSR) required in electric vehicle applications. This new controller, called the dual-mode inverter controller (DMIC) [1], can drive both the Permanent Magnet Synchronous Machine with sinusoidal back emf, and the brushless dc machine (BDCM) with trapezoidal emf as a motor or generator. Here we concentrate on the application of the DMIC to the operation of the BDCM in the motoring mode. Simulation results, supported by closed form analytical expressions, show that the CPSR of the DMIC driven BDCM is infinite when all of the motor and inverter loss mechanisms are neglected. The expressions further show that the ratio of high-to-low motor inductances accommodated by the DMIC is 11 making the DMIC compatible with both low-and highinductance BDCMs. Classical hysteresis-band motor current control used below base speed is integrated with DMICs phase advance above base speed. The power performance of the DMIC is then simulated across the entire speed range. Laboratory testing of a low-inductance, 7.5-hp BDCM driven by the DMIC demonstrated a CPSR above 6:1. Current peak and rms values remained controlled below rated values at all speeds. A computer simulation accurately reproduced the results of lab testing showing that the limiting CPSR of the test motor is 8:1.
AbstractThis paper presents a low-cost position sensorless control scheme for brushless dc motor... more AbstractThis paper presents a low-cost position sensorless control scheme for brushless dc motors. Rotor position infor-mation is extracted by indirectly sensing the back EMF from only one of the three motor-terminal voltages for a three-phase motor. Depending on the ...
AbstractThis paper presents a modified vector control algorithm for a fractional-slot concentrat... more AbstractThis paper presents a modified vector control algorithm for a fractional-slot concentrated-winding surface per-manent magnet (SPM) machine that has been developed to max-imize the machine's partial-load efficiency over a wide range of operating ...
In this paper, a power line conditioner using a cascade multilevel inverter is presented for volt... more In this paper, a power line conditioner using a cascade multilevel inverter is presented for voltage regulation, reactive power (var) compensation, and harmonic filtering. The cascade M -level inverter consists of (M 0 1)=2 H bridges, in which each bridge has its own separate dc source. This new inverter can: 1) generate almost sinusoidal waveform voltage with only one time switching per line cycle; 2) eliminate transformers of multipulse inverters used in the conventional static var compensators; and 3) make possible direct connection to the 13.8-kV power distribution system in parallel and series without any transformer. In other words, the power line conditioner is much more efficient and more suitable to var compensation and harmonic filtering of distribution systems than traditional multipulse and pulsewidth modulation inverters. It has been shown that the new inverter is especially suited for var compensation. This paper focuses on feasibility and control schemes of the cascade inverter for voltage regulation and harmonic filtering in distribution systems. Analytical, simulated, and experimental results show the superiority of the new power line conditioner.
AbstractTraditional high-frequency pulse width modulation (PWM) inverters for motor drives have ... more AbstractTraditional high-frequency pulse width modulation (PWM) inverters for motor drives have several problems associated with their high frequency switching which produces high voltage change (dV/dt) rates. Multilevel inverters solve these problems because their devices switch at the fundamental frequency. Two different multilevel topologies are identified for use as a converter for electric drives, a cascade inverter with separate dc sources and a back-to-back diode clamped converter. The cascade inverter is a natural fit for large automotive electric drives because of the high VA ratings possible and because it uses several levels of dc voltage sources which would be available from batteries or fuel cells. The back-to-back diode clamped converter is ideal for use where a generator or alterntator produces ac voltage. Simulation and experimental results show the superiority of these two converters over PWM based drives.
Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings a... more Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings are being investigated as candidates for high-performance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constant-power speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque
Proceedings of PESC '95 - Power Electronics Specialist Conference, 1995
In this paper, a multilevel voltage-source converter system is proposed for high-voltage, high-po... more In this paper, a multilevel voltage-source converter system is proposed for high-voltage, high-power applications such as back-to-back interconnection of power systems, large induction motor drives, and electrical traction drives. Multilevel voltage-source converters have a voltage unbalance problem in the DC capacitors. The problem may be solved by use of additional voltage regulators or separate DC sources. However, these solutions are
... Downing, Mark [ORNL] ; Stahlhut, Ronnie D [ORNL] ; Bremmer, R. [John Deere -- Moline Tech Cen... more ... Downing, Mark [ORNL] ; Stahlhut, Ronnie D [ORNL] ; Bremmer, R. [John Deere -- Moline Tech Center] ; Shoemaker, JM [John Deere -- Moline Tech Center] ; Seksarian, AK [John Deere -- Moline Tech Center] ; Poore, B. [John Deere -- Moline Tech Center] ; Lutz, Jon F [ORNL]. ...
Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings a... more Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings are being investigated as candidates for high-performance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constant-power speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque
The reluctance interior permanent magnet (RIPM) motor is currently used by many leading auto manu... more The reluctance interior permanent magnet (RIPM) motor is currently used by many leading auto manufacturers for hybrid vehicles. The power density for this type of motor is high compared with that of induction motors and switched reluctance motors. The primary drawback of the RIPM motor is the permanent magnet (PM) because during high-speed operation, the fixed PM produces a huge back electromotive force (emf) that must be reduced before the current will pass through the stator windings. This reduction in back-emf is accomplished with a significant direct-axis (d-axis) demagnetization current, which opposes the PM's flux to reduce the flux seen by the stator wires. This may lower the power factor and efficiency of the motor and raise the requirement on the alternate current (ac) power supply; consequently, bigger inverter switching components, thicker motor winding conductors, and heavier cables are required. The direct current (dc) link capacitor is also affected when it must accommodate heavier harmonic currents. It is commonly agreed that, for synchronous machines, the power factor can be optimized by varying the field excitation to minimize the current. The field produced by the PM is fixed and cannot be adjusted. What can be adjusted is reactive current to the d-axis of the stator winding, which consumes reactive power but does not always help to improve the power factor. The objective of this project is to avoid the primary drawbacks of the RIPM motor by introducing brushless field excitation (BFE). This offers both high torque per ampere (A) per core length at low speed by using flux, which is enhanced by increasing current to a fixed excitation coil, and flux, which is weakened at high speed by reducing current to the excitation coil. If field weakening is used, the dc/dc boost converter used in a conventional RIPM motor may be eliminated to reduce system costs. However, BFE supports a drive system with a dc/dc boost converter, because it can further extend the constant power speed range of the drive system and adjust the field for power factor and efficiency gains. Lower core losses at low torque regions, especially at high speeds, are attained by reducing the field excitation. Safety and reliability are increased by weakening the field when a winding short-circuit fault occurs, preventing damage to the motor. For a high-speed motor operating at 16,000-revolutions per minute (rpm), mechanical stress is a challenge. Bridges that link the rotor punching segments together must be thickened for mechanical integrity; consequently, increased rotor flux leakage significantly lowers motor performance. This barrier can be overcome by BFE to ensure sufficient rotor flux when needed.
A 30 pole, 6 kW, and 6000 maximum revolutions per minute (rpm) prototype of the permanent magnet ... more A 30 pole, 6 kW, and 6000 maximum revolutions per minute (rpm) prototype of the permanent magnet synchronous motor (PMSM) with fractional-slot concentrated windings (FSCW) has been designed, built, and tested at the University of Wisconsin at Madison (UWM). This ...
... Kelly S. Samons, Roy L. Kessinger Visual Computing System ... Soc. Ann. Mtg., pp. 1339-1345. ... more ... Kelly S. Samons, Roy L. Kessinger Visual Computing System ... Soc. Ann. Mtg., pp. 1339-1345. 2. M. Lajoie-Mazenc, C. Villanueva, J. Hector, Study and Implementation of Hysteresis Controlled Inverter on a Permanent Magnet Synchronous Machine, Conf. Rec. 1984 IEEE Ind. ...
IECON'01. 27th Annual Conference of the IEEE Industrial Electronics Society (Cat. No.37243), 2001
This paper presents modular permanent magnet (PM) motor drives for automotive traction applicatio... more This paper presents modular permanent magnet (PM) motor drives for automotive traction applications. A partially modularized drive system consisting of a single PM motor and multiple inverters is described. The motor has multiple three-phase stator winding sets and each winding set is driven with a separate three-phase inverter module. A truly modularized inverter and motor configuration based on an axial-gap PM motor is then introduced, in which identical PM motor modules are mounted on a common shaft and each motor module is powered by a separate inverter module. The advantages of the modular approach for both inverter and motor include: 1) power rating scalability -one design meets different power requirements by simply stacking an adequate number of modules, thus avoiding redesigning and reducing the development cost, 2) increased fault tolerance, and 3) easy repairing. A prototype was constructed by using two inverters and an axial-gap PM motor with two sets of three-phase stator windings, and it is used to assist the diesel engine in a hybrid electric vehicle converted from a Chevrolet Suburban. The effect of different pulse-width-modulation strategies for both motoring and regenerative modes on current control is analyzed. Torque and regenerative control algorithms are implemented with a digital signal processor. Analytical and initial testing results are included in the paper.
An inverter topology and control scheme has been developed that can drive low-inductance, surface... more An inverter topology and control scheme has been developed that can drive low-inductance, surface-mounted permanent magnet motors over the wide constant power speed range required in electric vehicle applications. This new controller is called the dual-mode inverter control (DMIC) [1]. The DMIC can drive either the Permanent Magnet Synchronous Machine (PMSM) with sinusoidal back emf, or the brushless dc machine (BDCM) with trapezoidal emf in the motoring and regenerative braking modes. In this paper we concentrate on the BDCM under high-speed motoring conditions. Simulation results show that if all motor and inverter loss mechanisms are neglected, the constant power speed range of the DMIC is infinite. The simulation results are supported by closed form expressions for peak and rms motor current and average power derived from analytical solution to the differential equations governing the DMIC/BDCM drive for the lossless case. The analytical solution shows that the range of motor in...
The differential equations that describe the operation of the brushless dc motor (BDCM) driven by... more The differential equations that describe the operation of the brushless dc motor (BDCM) driven by dual mode inverter control (DMIC) are solved analytically. Explicit expressions for peak and rms motor current and average motor power are derived. The analysis is performed neglecting all motor loss mechanisms. The results provide a theoretical verification that the constant power speed range (CPSR) of the BDCM is infinite when driven by the DMIC. While speed sensitive motor losses limit the CPSR of any practical drive to a finite value, there is no inherent limitation imposed by the DMIC. The analytic formulas provide useful drive design guidance without requiring simulation or laboratory experimentation.
A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc... more A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.
The exact analytical formulas for radial action of the Kratzer and Davidson rotating vibrators an... more The exact analytical formulas for radial action of the Kratzer and Davidson rotating vibrators and the WKB approximation for the radial action of Dunham's one-dimensional rotating vibrator have indicated that the form of the action is Ir = h[v+1/2+ε{J(J+1)}] The correctness of this form was verified through use in the Rydberg-Klein method which was analytically applied to energy eigenvalue formulas
Previous theoretical work has shown that when all loss mechanisms are neglected the constant powe... more Previous theoretical work has shown that when all loss mechanisms are neglected the constant power speed range (CPSR) of a brushless dc motor (BDCM) is infinite when the motor is driven by the dual-mode inverter control (DMIC) (1,2). In a physical drive, losses, particularly speed-sensitive losses, will limit the CPSR to a finite value. In this paper we report the results of laboratory testing of a low-inductance, 7.5-hp BDCM driven by the DMIC. The speed rating of the test motor rotor limited the upper speed of the testing, and the results show that the CPSR of the test machine is greater than 6:1 when driven by the DMIC. Current wave shape, peak, and rms values remained controlled and within rating over the entire speed range. The laboratory measurements allowed the speed-sensitive losses to be quantified and incorporated into computer simulation models, which then accurately reproduce the results of lab testing. The simulator shows that the limiting CPSR of the test motor is 8:1....
An inverter topology and control scheme has been developed and tested to demonstrate that it can ... more An inverter topology and control scheme has been developed and tested to demonstrate that it can drive low-inductance, surface mounted permanent magnet motors over the wide constant power speed range (CPSR) required in electric vehicle applications. This new controller, called the dual-mode inverter controller (DMIC) [1], can drive both the Permanent Magnet Synchronous Machine with sinusoidal back emf, and the brushless dc machine (BDCM) with trapezoidal emf as a motor or generator. Here we concentrate on the application of the DMIC to the operation of the BDCM in the motoring mode. Simulation results, supported by closed form analytical expressions, show that the CPSR of the DMIC driven BDCM is infinite when all of the motor and inverter loss mechanisms are neglected. The expressions further show that the ratio of high-to-low motor inductances accommodated by the DMIC is 11 making the DMIC compatible with both low-and highinductance BDCMs. Classical hysteresis-band motor current control used below base speed is integrated with DMICs phase advance above base speed. The power performance of the DMIC is then simulated across the entire speed range. Laboratory testing of a low-inductance, 7.5-hp BDCM driven by the DMIC demonstrated a CPSR above 6:1. Current peak and rms values remained controlled below rated values at all speeds. A computer simulation accurately reproduced the results of lab testing showing that the limiting CPSR of the test motor is 8:1.
AbstractThis paper presents a low-cost position sensorless control scheme for brushless dc motor... more AbstractThis paper presents a low-cost position sensorless control scheme for brushless dc motors. Rotor position infor-mation is extracted by indirectly sensing the back EMF from only one of the three motor-terminal voltages for a three-phase motor. Depending on the ...
AbstractThis paper presents a modified vector control algorithm for a fractional-slot concentrat... more AbstractThis paper presents a modified vector control algorithm for a fractional-slot concentrated-winding surface per-manent magnet (SPM) machine that has been developed to max-imize the machine's partial-load efficiency over a wide range of operating ...
In this paper, a power line conditioner using a cascade multilevel inverter is presented for volt... more In this paper, a power line conditioner using a cascade multilevel inverter is presented for voltage regulation, reactive power (var) compensation, and harmonic filtering. The cascade M -level inverter consists of (M 0 1)=2 H bridges, in which each bridge has its own separate dc source. This new inverter can: 1) generate almost sinusoidal waveform voltage with only one time switching per line cycle; 2) eliminate transformers of multipulse inverters used in the conventional static var compensators; and 3) make possible direct connection to the 13.8-kV power distribution system in parallel and series without any transformer. In other words, the power line conditioner is much more efficient and more suitable to var compensation and harmonic filtering of distribution systems than traditional multipulse and pulsewidth modulation inverters. It has been shown that the new inverter is especially suited for var compensation. This paper focuses on feasibility and control schemes of the cascade inverter for voltage regulation and harmonic filtering in distribution systems. Analytical, simulated, and experimental results show the superiority of the new power line conditioner.
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Papers by John Mckeever