• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.213-214
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• 2014

This paper compares two instantaneous reactive power definitions in DFIG wind turbine with a back-to-back three-level neutral-point clamped voltage source converter under unbalanced grid conditions. In general, conventional definition of instantaneous reactive power is obtained by taking an imaginary component of complex power. The other definition of instantaneous reactive power can be developed based on a set of voltages lagging the grid input voltages by 90 degree. A complex quantity referred as a quadrature complex power is defined. Proposed definition of instantaneous reactive power is derived by taking a real component of quadrature complex power. The characteristics of two instantaneous reactive power definitions are compared using the ripple-free stator active power control algorithm in DFIG. Instantaneous reactive power definition based on quadrature complex power has a simpler current reference calculation control block. Ripple of instantaneous active and reactive power has the same magnitude unlike in conventional definition under grid unbalance. Comparison results of two instantaneous reactive power definitions are verified through simulation.

• Proceedings of the KIEE Conference
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• 1999.07f
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• pp.2481-2483
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• 1999

This paper proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers $q_{q}$, $q_{r}$ were defined. The three power components are linearly independent, so the compensation for the two instantaneous reactive powers leads to control the two components of the current space vector. With the theory, the neutral current of a three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storage element.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.10
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• pp.1303-1307
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• 2018

A improving sensorless compensator for the IPMSM(Interior Permanent Magnet Synchronous Motor) drive system is proposed. Generally, the motor drive system is required the robust parameter variation and disturbance. The speed estimation methods of the conventional IRP(Instantaneous Reactive Power) compensator is improved by the speed estimation techniques of the current model observer with the proposed instantaneous reactive power compensator. Performance evaluations of the novel speed error compensator and sensorless control system are carried out by the experiments.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.54 no.2
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• pp.71-80
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• 2005

This paper presents the position sensorless vector control of a cylindrical permanent magnet synchronous motor(PMSM) in the field weakening region. The position sensorless algorithm using an instantaneous reactive power of the PMSM is proposed. An instantaneous reactive power can be obtained from the vector product of rotor currents and back emf of the PMSM. Back emf includes the information of rotor speed. So the estimated speed can be yielded from the voltage equation of the PMSM. In other words, the estimated speed is compensated by using an instantaneous reactive power. To extend the speed range of the PMSM in the constant horsepower region, the field weakening control is applied. The proposed algorithm is not affected by mechanical motor parameters because the mechanical equation is not used. The effectiveness of the proposed algorithm is verified by the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.2
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• pp.107-115
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• 2006

In this paper, a new speed sensorless control based on an instantaneous reactive power is proposed for the interior permanent magnet synchronous motor(IPMSM) drives. In proposed algorithm, the current observer estimates the line currents and the estimated speed can be yielded from the voltage equation because the information of speed is included in back EMF. To implement speed sensorless control, the current observer is composed by using the voltage equation of the IPMSM in the stationary reference frame fixed to the stator. The estimated speed of the rotor is composed by using the voltage equation of the IPMSM in the rotating reference frame fixed to the rotor The estimated speeds to minimize the speed error compensated by using the instantaneous reactive power. The instantaneous reactive power is calculated on the rotating reference frame fixed to the rotor. The effectiveness of the preposed algorithm is confirmed by the experiments.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.131-133
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• 1998

This paper, proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers $q_{q}$, $q_{r}$ were defined. The three power components are linearly independent, so the compensation for the two instantaneous reactive powers leads to control the two components of the current space vector. With the theory, the neutral current of the three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storage element.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.6
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• pp.678-682
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• 1999

In this paper, we propose the algorithm which can control active power and reactive power independently in Battery Energy Storage System. The proposed algorithm is based on the instantaneous power theory that the inner product of the voltage vector and current vector represents the active power and the cross product of those represents the reactive power, and it can control active power and reactive power independently. To verify the validity of the proposed algorithm, we make model of the real power system in th KERI and simulate this algorithm. As a result of this simulation, we verified that the proposed algorithm can control active power and reactive power independently.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.11
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• pp.577-585
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• 2003

This paper proposes a new speed sensorless control method of a permanent magnet synchronous motor using an instantaneous reactive power. In the proposed algorithm, the line currents are estimated by a observer and the estimated speed can be yielded from the voltage equation because the information of speed is included in back emf. But the speed estimation error between the estimated and the real speeds is occured by errors due to measuring the motor parameters and sensing the line current and the input voltage. To minimize the speed estimation error, the estimated speed is compensated by using an instantaneous reactive power. In this paper, the proposed algorithm is not affected by mechanical motor parameters because the mechanical equation is not used. The effectiveness of algorithm is confirmed by the experiments.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.6
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• pp.330-335
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• 1999

This paper proposed the p-q-r coordinate system where the instantaneous active power p, and the two instantaneous reactive powers qq, qr were defined. The three power components are linearly independent, so the compensation for the two instantaneous reactive powers leads to control the two components of the current space vector. With the theory, the neutral current of a three-phase four-wire system can be eliminated by only compensating the instantaneous reactive power using no energy storge element.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.38 no.7
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• pp.539-548
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• 1989

This paper describes an instantaneous reactive power compensator aimed at the compensation of reactive power and current harmonics of a thyristor load. A new definition of the instantaneous reactive power consisting of both displacement of fundamental current and harmonic distortion current is proposed and the physical meaning is investigated from the viewpoint of an instantaneous power flow. The instantaneous reactive power is calculated from the feedback of instantaneous voltage, current and is compensated by the current controlled PWM converter connected in parallel with the load. The PWM converter operates as a high performance current control scheme, because adopts the excellent current controlled PWM technique based on the current deviation vector. Both simulation and experimental results show good compensating performances in steady and transient state.