The Experts below are selected from a list of 345 Experts worldwide ranked by ideXlab platform
D.g. Holmes - One of the best experts on this subject based on the ideXlab platform.
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stationary Frame current regulation of pwm inverters with zero steady state error
IEEE Transactions on Power Electronics, 2003Co-Authors: D N Zmood, D.g. HolmesAbstract:Current regulators for AC inverters are commonly categorized as hysteresis, linear PI, or deadbeat predictive regulators, with a further sub-classification into stationary ABC Frame and Synchronous d-q Frame implementations. Synchronous Frame regulators are generally accepted to have a better performance than stationary Frame regulators, as they operate on DC quantities and hence can eliminate steady-state errors. This paper establishes a theoretical connection between these two classes of regulators and proposes a new type of stationary Frame regulator, the P+Resonant regulator, which achieves the same transient and steady-state performance as a Synchronous Frame PI regulator. The new regulator is applicable to both single-phase and three phase inverters.
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grid current regulation of a three phase voltage source inverter with an lcl input filter
IEEE Transactions on Power Electronics, 2003Co-Authors: Erika Twining, D.g. HolmesAbstract:Many grid connected power electronic systems, such as STATCOMs, UPFCs, and distributed generation system interfaces, use a voltage source inverter (VSI) connected to the supply network through a filter. This filter, typically a series inductance, acts to reduce the switching harmonics entering the distribution network. An alternative filter is a LCL network, which can achieve reduced levels of harmonic distortion at lower switching frequencies and with less inductance, and therefore has potential benefits for higher power applications. However, systems incorporating LCL filters require more complex control strategies and are not commonly presented in literature. This paper proposes a robust strategy for regulating the grid current entering a distribution network from a three-phase VSI system connected via a LCL filter. The strategy integrates an outer loop grid current regulator with inner capacitor current regulation to stabilize the system. A Synchronous Frame PI current regulation strategy is used for the outer grid current control loop. Linear analysis, simulation, and experimental results are used to verify the stability of the control algorithm across a range of operating conditions. Finally, expressions for ""harmonic impedance" of the system are derived to study the effects of supply voltage distortion on the harmonic performance of the system.
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stationary Frame harmonic reference generation for active filter systems
IEEE Transactions on Industry Applications, 2002Co-Authors: M J Newman, D N Zmood, D.g. HolmesAbstract:Harmonic reference generators for active filter systems are commonly implemented in the Synchronous reference Frame, so that simple low- or high-pass filter functions can be used depending on the requirements of a particular application. High-pass filters in particular are used when the reference generator is required to produce an "everything but the fundamental" target waveform. This paper presents a stationary Frame notch filter equivalent to a high-pass Synchronous Frame harmonic reference generator for such systems. The use of the stationary Frame allows for quicker calculation of the reference generation in a discrete digital implementation, and also allows classical control techniques to be used to analyze the active filter system without requiring Synchronous Frame transformations of the outside system model. Both simulation (continuous and discrete) and experimental results showing the equivalency of the stationary and Synchronous Frame reference generation process are presented using both shift and delta-operator-based infinite-impulse response digital filters.
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stationary Frame harmonic reference generation for active filter systems
Applied Power Electronics Conference, 2002Co-Authors: M J Newman, D N Zmood, D.g. HolmesAbstract:Harmonic reference generators for active power filter systems are commonly implemented in the Synchronous reference Frame, so that simple low or high pass filter functions can be used depending on the requirements of a particular application. High pass filters in particular are used when the reference generator is required to produce an "everything but the fundamental" target waveform. This paper presents a stationary Frame notch filter equivalent to a high pass Synchronous Frame harmonic reference generator for such systems. The use of the stationary Frame allows for quicker calculation of the reference generation in a discrete digital implementation, and also allows classical control techniques to be used to analyze the active filter system without requiring Synchronous Frame transformations of the outside system model. Both simulation (continuous and discrete) and experimental results showing the equivalency of the stationary and Synchronous Frame reference generation process are presented using both shift and delta operator based IIR digital filters.
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frequency domain analysis of three phase linear current regulators
IEEE Industry Applications Society Annual Meeting, 1999Co-Authors: D N Zmood, D.g. Holmes, G H BodeAbstract:Stationary Frame linear PI current regulators are conventionally regarded as unsatisfactory for AC systems because they cannot eliminate steady state errors. Consequently, Synchronous Frame regulators are perceived to be superior, since they achieve zero steady state error by acting on DC signals in a rotating Frame of reference. However, a Synchronous Frame regulator is more complex, and requires in particular a way of transforming a measured stationary Frame AC current (or error) to rotating Frame DC quantities, and transforming the resultant control action back to the stationary Frame for implementation. This paper presents a technique for interpreting the stationary/rotating Frame transformations as modulation processes in the Laplace domain which move the control function from one part of the frequency spectrum to another. The technique is used to compare stationary and Synchronous Frame PI regulators on a common basis to better understand the advantages of a Synchronous Frame regulator, and then to develop a new form of stationary Frame resonant regulator which achieves zero steady state error without requiring the complex transformations of a Synchronous Frame regulator. The performance of this new regulator is evaluated and found to be equivalent to that of the Synchronous Frame PI regulator.
Robert D Lorenz - One of the best experts on this subject based on the ideXlab platform.
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Synchronous Frame pi current regulators in a virtually translated system
IEEE Industry Applications Society Annual Meeting, 2004Co-Authors: Hyunbae Kim, Robert D LorenzAbstract:This paper presents a virtual translation technique for current regulation for AC machines. A virtual physical parameter is employed to effectively translate the system pole to achieve fast and robust dynamics. Applying this technique to conventional Synchronous Frame current regulators reduces parameter sensitivity and improves robustness. The current controllers are redesigned in the virtually translated system. Current regulators adopting the technique have been analyzed in complex vector form for symmetric AC machines and in scalar form for salient-pole AC machines. Several current regulators using this technique have been experimentally evaluated for different operating conditions in an IPMSM drive.
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decoupled control of a four leg inverter via a new 4 spl times 4 transformation matrix
IEEE Transactions on Power Electronics, 2001Co-Authors: M J Ryan, R W De Doncker, Robert D LorenzAbstract:Four-leg (3-phase 4-wire) inverters are developed to power unbalanced/nonlinear three-phase loads. A unique 4/spl times/4 decoupling transformation matrix is used that enables direct transformation between the four degree-of-freedom (DOF) leg-modulation space of the inverter and its corresponding 3-DOF output-voltage space. This is analogous to the well-known 3/spl times/3 "abc-qd" transformation developed for the three-leg inverter. Details of this new 4/spl times/4 "Quad" transform are provided, along with a depiction of the voltage-vectors produced. Advanced Synchronous-Frame control techniques are applied with this 4-to-3 "abcn-qdo" transform to create a UPS-style inverter with sinewave output. Experimental results for an 8.6 kVA prototype inverter are presented.
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decoupled control of a 4 leg inverter via a new 4 spl times 4 transformation matrix
Power Electronics Specialists Conference, 1999Co-Authors: M J Ryan, R W De Doncker, Robert D LorenzAbstract:Four-leg (3-phase 4-wire) inverters are developed to power unbalanced/nonlinear three-phase loads. A unique 4/spl times/4 decoupling transformation matrix is used that enables direct transformation between the four degree-of-freedom (DOF) leg-modulation space of the inverter and its corresponding 3-DOF output-voltage v space. This is analogous to the well-known 3/spl times/3 "abc-qd" transformation developed for the 3-leg inverter. Details of this new 4/spl times/4 "Quad" transform are provided, along with a depiction of the voltage-vectors produced. Advanced Synchronous-Frame control techniques are applied with this 4-to-3 "abcn-qdo" transform to create a UPS-style inverter with sinewave output. Experimental results for an 8.6 kV a prototype inverter are presented.
D N Zmood - One of the best experts on this subject based on the ideXlab platform.
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stationary Frame current regulation of pwm inverters with zero steady state error
IEEE Transactions on Power Electronics, 2003Co-Authors: D N Zmood, D.g. HolmesAbstract:Current regulators for AC inverters are commonly categorized as hysteresis, linear PI, or deadbeat predictive regulators, with a further sub-classification into stationary ABC Frame and Synchronous d-q Frame implementations. Synchronous Frame regulators are generally accepted to have a better performance than stationary Frame regulators, as they operate on DC quantities and hence can eliminate steady-state errors. This paper establishes a theoretical connection between these two classes of regulators and proposes a new type of stationary Frame regulator, the P+Resonant regulator, which achieves the same transient and steady-state performance as a Synchronous Frame PI regulator. The new regulator is applicable to both single-phase and three phase inverters.
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stationary Frame harmonic reference generation for active filter systems
IEEE Transactions on Industry Applications, 2002Co-Authors: M J Newman, D N Zmood, D.g. HolmesAbstract:Harmonic reference generators for active filter systems are commonly implemented in the Synchronous reference Frame, so that simple low- or high-pass filter functions can be used depending on the requirements of a particular application. High-pass filters in particular are used when the reference generator is required to produce an "everything but the fundamental" target waveform. This paper presents a stationary Frame notch filter equivalent to a high-pass Synchronous Frame harmonic reference generator for such systems. The use of the stationary Frame allows for quicker calculation of the reference generation in a discrete digital implementation, and also allows classical control techniques to be used to analyze the active filter system without requiring Synchronous Frame transformations of the outside system model. Both simulation (continuous and discrete) and experimental results showing the equivalency of the stationary and Synchronous Frame reference generation process are presented using both shift and delta-operator-based infinite-impulse response digital filters.
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stationary Frame harmonic reference generation for active filter systems
Applied Power Electronics Conference, 2002Co-Authors: M J Newman, D N Zmood, D.g. HolmesAbstract:Harmonic reference generators for active power filter systems are commonly implemented in the Synchronous reference Frame, so that simple low or high pass filter functions can be used depending on the requirements of a particular application. High pass filters in particular are used when the reference generator is required to produce an "everything but the fundamental" target waveform. This paper presents a stationary Frame notch filter equivalent to a high pass Synchronous Frame harmonic reference generator for such systems. The use of the stationary Frame allows for quicker calculation of the reference generation in a discrete digital implementation, and also allows classical control techniques to be used to analyze the active filter system without requiring Synchronous Frame transformations of the outside system model. Both simulation (continuous and discrete) and experimental results showing the equivalency of the stationary and Synchronous Frame reference generation process are presented using both shift and delta operator based IIR digital filters.
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frequency domain analysis of three phase linear current regulators
IEEE Industry Applications Society Annual Meeting, 1999Co-Authors: D N Zmood, D.g. Holmes, G H BodeAbstract:Stationary Frame linear PI current regulators are conventionally regarded as unsatisfactory for AC systems because they cannot eliminate steady state errors. Consequently, Synchronous Frame regulators are perceived to be superior, since they achieve zero steady state error by acting on DC signals in a rotating Frame of reference. However, a Synchronous Frame regulator is more complex, and requires in particular a way of transforming a measured stationary Frame AC current (or error) to rotating Frame DC quantities, and transforming the resultant control action back to the stationary Frame for implementation. This paper presents a technique for interpreting the stationary/rotating Frame transformations as modulation processes in the Laplace domain which move the control function from one part of the frequency spectrum to another. The technique is used to compare stationary and Synchronous Frame PI regulators on a common basis to better understand the advantages of a Synchronous Frame regulator, and then to develop a new form of stationary Frame resonant regulator which achieves zero steady state error without requiring the complex transformations of a Synchronous Frame regulator. The performance of this new regulator is evaluated and found to be equivalent to that of the Synchronous Frame PI regulator.
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stationary Frame current regulation of pwm inverters with zero steady state error
Power Electronics Specialists Conference, 1999Co-Authors: D N Zmood, D.g. HolmesAbstract:Current regulators for AC inverters are commonly categorised as hysteresis, linear PI or deadbeat predictive, with a further subclassification into stationary ABC Frame and Synchronous DQ Frame implementations. Synchronous Frame controllers are generally accepted to have a better performance than stationary Frame controllers do, as they operate on DC quantities and hence can eliminate steady state errors. This paper establishes a theoretical connection between these two classes of regulators and proposes a new type of stationary Frame controller, which achieves the same steady state performance as a Synchronous Frame controller. The new controller is applicable to both single phase and three phase inverters.
Seungki Sul - One of the best experts on this subject based on the ideXlab platform.
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novel anti windup of a current regulator of a surface mounted permanent magnet motor for flux weakening control
IEEE Industry Applications Society Annual Meeting, 2005Co-Authors: Taesuk Kwon, Seungki SulAbstract:This paper proposes a novel antiwindup method of current regulator for the drive system of a surface-mounted permanent-magnet Synchronous motor at flux-weakening region. It is designed in conjunction with the Synchronous-Frame proportional and integral current regulator and the space vector pulse width modulation. The difference between the regulator output voltage and the saturated voltage on the q-axis of the regulator is used for flux-weakening control, which modifies the d-axis current reference. With this method, the antiwindup and the flux-weakening control can be achieved simultaneously. Since the proposed method utilizes the dc-link voltage more efficiently, it makes the motor generate higher output torque than the conventional antiwindup and/or flux-weakening control methods under the same voltage and current limitation. The effectiveness of this method is confirmed by computer simulations and experiments
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Synchronous Frame current control of multi phase Synchronous motor part ii asymmetric fault condition due to open phases
IEEE Industry Applications Society Annual Meeting, 2004Co-Authors: Hyungmin Ryu, Jiwoong Kim, Seungki SulAbstract:In this paper, the Synchronous Frame current controller of a multi-phase Synchronous motor with open phases is proposed. The proposed method can not only possess the superiority of a linear controller over the conventional hysteresis-type current controller but it also enables the current to be regulated without a steady state error. The key idea is that all the harmonics of the current and voltage, which can still contribute to the torque positively, can be equivalently represented as dc components even under asymmetric fault conditions. Through out this paper, a five-phase Synchronous motor with one open phase is used as a practical example and the basic concepts can be easily extended into an n-phase ac motor with multiple open phases, which has the arbitrary number or configuration of the remaining healthy phases. Experimental results prove the validity of the proposed modeling and control algorithm.
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Synchronous Frame current control of multi phase Synchronous motor part i modeling and current control based on multiple d q spaces concept under balanced condition
IAS annual meeting, 2004Co-Authors: Hyungmin Ryu, Jiwoong Kim, Seungki SulAbstract:In this paper, the Synchronous Frame current control of a multi-phase Synchronous motor based on multiple d-q spaces concept is proposed. The proposed method can not only possess the superiority of a linear controller over the conventional hysteresis-type current controller but it also enables the current to be regulated without a steady state error. The key idea is that all the harmonics of the current and voltage, which can contribute to the torque positively, can be equivalently represented as dc components. Through out this paper, a five-phase Synchronous motor is used as a practical example and the basic concepts can be easily extended into an n-phase ac motor. Experimental results prove the validity of the proposed method.
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a compensation method for time delay of full digital Synchronous Frame current regulator of pwm ac drives
IEEE Industry Applications Society Annual Meeting, 2001Co-Authors: Bonho Bae, Seungki SulAbstract:The voltage output is inevitably delayed in a full-digital implementation of a current regulator due to an arithmetic calculation and the pulsewidth modulation. In the case of the Synchronous Frame current regulator, the time delay is accompanied by a Frame rotation. In some applications where the ratio of the sampling frequency to the output frequency is insufficient, such as a high-power drive or a super-high-speed drive, the effect of the Frame rotation during the delay time causes a phase and magnitude error in the voltage output. The error degrades the dynamic performance and can cause instability in the current regulator at high speed. It is also intuitively known that advancing the phase of the voltage output can mitigate this instability. In this paper, the errors in the voltage output and the instability problems have been studied analytically and a compensation method for the error is proposed. Using a computer simulation and complex root locus analysis, a comparative study with conventional methods has been carried out and the utility of the proposed method has been verified experimentally.
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fast current controller in three phase ac dc boost converter using d q axis crosscoupling
Power Electronics Specialists Conference, 1996Co-Authors: Jongwoo Choi, Seungki SulAbstract:In this paper, a new simple current controller with both satisfactory steady-state characteristics and fast transient response is proposed. In this scheme, a reference modification part is incorporated with the generally used Synchronous-Frame proportional-integral (PI) controller for the fast transient response. Simulation and experimental results are presented and show the effectiveness of the proposed current controller. In the simulation and experimental results, both the current controller and DC-link regulator show conspicuous performance improvement. It is also observed in the simulation and experiment that the proposed current controller has a similar characteristic as the Synchronous-Frame PI controller in the steady state and as the minimum-time current controller in the transient state.
M J Ryan - One of the best experts on this subject based on the ideXlab platform.
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decoupled control of a four leg inverter via a new 4 spl times 4 transformation matrix
IEEE Transactions on Power Electronics, 2001Co-Authors: M J Ryan, R W De Doncker, Robert D LorenzAbstract:Four-leg (3-phase 4-wire) inverters are developed to power unbalanced/nonlinear three-phase loads. A unique 4/spl times/4 decoupling transformation matrix is used that enables direct transformation between the four degree-of-freedom (DOF) leg-modulation space of the inverter and its corresponding 3-DOF output-voltage space. This is analogous to the well-known 3/spl times/3 "abc-qd" transformation developed for the three-leg inverter. Details of this new 4/spl times/4 "Quad" transform are provided, along with a depiction of the voltage-vectors produced. Advanced Synchronous-Frame control techniques are applied with this 4-to-3 "abcn-qdo" transform to create a UPS-style inverter with sinewave output. Experimental results for an 8.6 kVA prototype inverter are presented.
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decoupled control of a 4 leg inverter via a new 4 spl times 4 transformation matrix
Power Electronics Specialists Conference, 1999Co-Authors: M J Ryan, R W De Doncker, Robert D LorenzAbstract:Four-leg (3-phase 4-wire) inverters are developed to power unbalanced/nonlinear three-phase loads. A unique 4/spl times/4 decoupling transformation matrix is used that enables direct transformation between the four degree-of-freedom (DOF) leg-modulation space of the inverter and its corresponding 3-DOF output-voltage v space. This is analogous to the well-known 3/spl times/3 "abc-qd" transformation developed for the 3-leg inverter. Details of this new 4/spl times/4 "Quad" transform are provided, along with a depiction of the voltage-vectors produced. Advanced Synchronous-Frame control techniques are applied with this 4-to-3 "abcn-qdo" transform to create a UPS-style inverter with sinewave output. Experimental results for an 8.6 kV a prototype inverter are presented.
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a Synchronous Frame controller for a single phase sine wave inverter
Applied Power Electronics Conference, 1997Co-Authors: M J Ryan, R D LorenzAbstract:A Synchronous Frame controller for a single-phase PWM inverter with an LC output filter is presented. These types of inverters are often used in uninterruptible power supplies (UPS) where a sinewave output voltage is to be maintained. The advantages of a Synchronous Frame regulator are well known in three-phase controllers where regulated AC variables (voltage, current, flux) are "-rotated" into a Frame Synchronous to the fundamental output frequency where they appear as DC vector quantities. Such a controller can regulate the steady-state errors of the corresponding DC quantities to zero. While the familiar dq transformation is not applicable in a single-phase system, a Frame Synchronous to the output fundamental can be formed by recognizing that the filter capacitor current and the filter capacitor voltage are identically 90/spl deg/ out of phase. Thus, orthogonal quantities much like dq components exist, and can be used to create a rotating Frame where a composite reference vector can be summed with a similar measured vector. Simulations of a Synchronous controller and a conventional state-feedback cascaded controller are presented and compared. Preliminary experimental results are also presented.
