• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.978-980
• /
• 2000

Sensorless PMSM is much studied for the industrial applications and home appliances because, a mechanical sensor reduces reliability and increases cost. Two types of instantaneous torque controls are basically used for high performance variable-speed a.c. drive : vector control and direct torque control. This paper investigates speed sensorless control of PMSM using direct torque control. The switching of inverter is determined from SVPWM realizing the command voltage which is obtained by flux error and measured current without d-q transformation. The rotor speed is estimated through adaptive observer with feedback loop. The simulation and experimental results indicate good performances.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.20 no.3
• /
• pp.232-238
• /
• 2015

A sensorless control algorithm of brushless DC (BLDC) motors with a model current based on 120 degree conduction mode is proposed in this paper. The rotor speed and position can be estimated using the current model of BLDC motor, which is a modified version of the conventional current model of permanent magnet synchronous motor. The rotor speed and position can be obtained using the difference of the actual current and the model current. The position error caused by the parameter errors of the model current is compensated using a PI controller and the feedback loop of the real current. The validity of the proposed sensorless control algorithm is verified through simulation.

• Proceedings of the KIEE Conference
• /
• 2006.04b
• /
• pp.251-253
• /
• 2006

Speed and torque controls of permanent magnet synchronous motors are usually attained by the application of position and speed sensors. However, speed and position sensors require the additional mounting space, reduce the reliability in harsh environments and increase the cost of a motor. Therefore, many studies have been performed for the elimination of speed and position sensors. This paper investigates a novel sensorless control of a permanent magnet synchronous motor. The proposed control strategy utilizes the active and reactive torque control for maximizing the active torque of a sensorless PMSM. The proposed algorithm is verified through the simulation and experimentation.

• Proceedings of the KIPE Conference
• /
• 2003.11a
• /
• pp.123-126
• /
• 2003

This paper proposes a speed-sensorless induction motor control system using the rotor flux error. The rotor flux observer uses the reduced- dimensional state estimator technique instead of directly measuring the rotor flux. The estimated rotor speed is obtained directly from the electrical frequency, the slip frequency, and the rotor speed compensation with the estimated q-axis rotor flux. To precisely estimate the rotor flux, the actual value of the stator resistance, whose actual variation is reflected, is derived. For fast calculation and improved performance of the proposed algorithm, all control functions are implemented in software using a digital signal processor (DSP) with its environmental circuits. Also, it is shown through experimental results that the proposed system gives good performance for the speed-sensorless induction motor control.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.10
• /
• pp.2299-2304
• /
• 2010

A sensorless vector control of an induction motor provides a good performance in the middle and high speed region. However, in the low speed region, it is very difficult to implement the sensorless vector controller because the feeding voltage measured by the motor is very low. In this paper, we designed the sensorless vector controller of an induction motor using the estimate of the slip frequency. To verify the performance of the proposed controller, an experiment has been performed.

• Proceedings of the KIPE Conference
• /
• 2007.11a
• /
• pp.7-10
• /
• 2007

The current model based sensorless method has many benefits that it can be robust control for large load torque. However, this method should determine a coefficient of back electro motive force(back-emf). This coefficient is varied by load torque and speed. Also, the coefficient determining equation is not exist, so it is determined only by experiment. On the other hands, using only back-emf estimatior method can not drive in low speed area and it has weakness in load variation. For these problems, this paper suggests the hybrid sensorless method that mixes the back-emf estimator regarding saliency and the current based sensorless model. This estimator offers not only non-necessary coefficient for current sensorless model, but also wide speed area operating in no specific transition method.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.22 no.1
• /
• pp.53-59
• /
• 2017

The information on the actual voltages and actual currents of the motor is required for the sensorless control of a permanent magnet synchronous motor without rotor position sensors. In the model-based rotor position estimator of a PM synchronous motor, the reference voltages, which are the outputs of the current controller, are commonly used. The reference voltages in over-modulation regions for high-speed operation differ from the actual voltages applied to the motor. Consequently, the estimated rotor position and rotor speed may fail to track the real rotor position and real rotor speed. In this paper, the sensorless control for a PM synchronous motor in over-modulation regions for high-speed operation is proposed. The three-phase voltages applied to the motor are measured by using additional voltage detection circuits, and the performance of the rotor position estimator based on the measured three-phase voltages is validated through the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.48 no.8
• /
• pp.426-430
• /
• 1999

In this paper, a speed sensorless algorithm for a high-speed induction motor is proposed. The proposed algorithm simply estimates rotor speed by integrating the deviation between the command current value of a controller and the real current value of the motor. To estimate rotor speed without a speed sensor, a fuzzy speed controller and a neural network speed estimator are applied. Computer simulation and implementation of the proposed system is described.

• Journal of Power Electronics
• /
• v.2 no.2
• /
• pp.146-153
• /
• 2002

this paper presents an implementation of digital control system of speed sensorless for Reluctance Synchronous Motor (RSM) drives with direct torque control (DTC). The problem of DTC for high-dynamic performance RSM drive is generating a nonlinear torque due to a saturated nonlinear inductance curve with various load currents. The control system consists of stator flux observer, compensating inductance look-up table, rotor position/speed/torque estimator, two hysteresis band controllers, an optimal switching look-up table, IGBT voltage source unverter, and TMS320C31 DSP controller. The stator flux observer is based on the combined voltage and current model with stator flux feedback adapitve control that inputs are the compensated inductances, current and voltage sensing of motor terminal with estimated rotor angle for wide speed range. The rotor position is estimated rotor speed is determined by differentiation of the rotor position used only in the current model part of the flux observer for a low speed operation area. It does not requrie the knowledge of any montor paramenters, nor particular care for moter starting, In order to prove the suggested control algorithm, we have simulation and testing at actual experimental system. The developed sensorless control system is showing a good speed control response characterisitic result and high performance features in 20/1500 rpm with 1.0Kw RSM having 2.57 ratio of d/q reluctance.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.2 no.4
• /
• pp.429-435
• /
• 2013

This paper proposes a sensorless speed control based on a novel extension of the torque producing flux (active flux) observer for the surface mounted permanent magnet synchronous machines (SPMSM) without additional high frequency signal injection. From the estimated torque producing flux, the rotor position and speed can be calculated at low speed due to their independency. Therefore, no rotor position sensor is required. Two approaches of the torque producing flux observer are presented and compared. The results show the stability and robustness of the expansion of the torque producing flux observer at low speed for the SPMSM.