• Journal of Power Electronics
• /
• 제15권5호
• /
• pp.1256-1263
• /
• 2015

A novel vector control strategy for a permanent magnet synchronous motor (PMSM) based on the kinetic energy stored in the rotor is proposed in this paper. The novel strategy is composed of two closed loops, in which the current loop is the inner loop, and the kinetic energy serves as the outer loop. The theoretical basis and the design procedure of the two loops are given. The feasibility of the proposed control strategy is verified by experimental results. When compared with traditional vector control strategies, the proposed vector control strategy based on energy feedback has better dynamic performance. In addition, an effective estimation solution for the load variation is put forward.

• 한국항공운항학회지
• /
• 제23권2호
• /
• pp.63-68
• /
• 2015

This paper presents the algorithm for envelope protection of helicopters. The algorithm consists of two feedback control loops: inner loop and outer loop. As an inner loop control, model following control is designed to meet the ADS-33 handling qualities specification by minimizing the tracking errors between the responses of the actual model and those of the command filter. In order to implement envelope protection, saturation limiter is imposed to command channels in command filter, whose limits are computed corresponding to the envelope limit. Fast model predictive control is designed as an outer loop control to deal with saturation constraints generated by the inner loop envelope protection and also imposed by outer loop envelope protection variables. Simulation results show that the proposed algorithm yields good envelope protection performance.

• 제어로봇시스템학회논문지
• /
• 제21권11호
• /
• pp.1027-1033
• /
• 2015

For the attitude control of spacecraft, two variable-speed control moment gyros are proposed as main actuators in the article. Since a variable-speed control moment gyro (VSCMG) makes two control torques (gyroscopic torque and reaction torque), two VSCMGs are sufficient for controlling 3-axes attitude. Additionally, there are no singular conditions for two non-parallel VSCMGs. Since gyroscopic torque is usually much greater than reaction torque, the control performances of approximately 3 axes may not be the same. However, several missions can be accomplished by controlling two axes. For such missions, a selective axes control method is proposed. The method selects two axes for a certain task and controls the attitude of the selected axes. For the remaining axis, angular speed is controlled for stabilization. A hardware-in-the-loop simulation has been used to test VSCMG modules and to verify the proposed method. Two VSCMGs can be alternative actuators for small satellites.

• 전기학회논문지
• /
• 제63권4호
• /
• pp.559-564
• /
• 2014

A microgrid as a small scale power system is operated by the grid-connected mode and islanded mode. It is anticipated that the battery energy storage system (BESS) is able to be applied to the microgrid for stable power control, such as tie-line and smoothing control in the grid-connected mode and voltage and frequency control in the islanded mode. In this paper, a digital signal processor (DSP), Two BESS controllers based on TMS320F28335 of a microgrid are implemented and are tested to show control performance in the hardware-in-the loop simulation (HILS) system.

• International Journal of Control, Automation, and Systems
• /
• 제6권6호
• /
• pp.948-953
• /
• 2008

In high dynamic situations, the GPS carrier tracking loop requires a wide bandwidth to track a carrier signal because the Doppler frequency changes more rapidly with time. However, a wide bandwidth allows noises within the bandwidth of the tracking loop to pass through the loop filter. As these noises are used in the numerical controlled oscillator(NCO), the carrier tracking loop of a GPS receiver shows a degraded performance in high dynamic situations. To solve this problem, an adaptive two-stage Kalman filter, which offers the NCO a less noisy phase error, can be used. This filter is based on a carrier phase dynamic model and can adapt to an incomplete dynamic model and a quickly changed Doppler frequency. The performance of the proposed tracking loop is verified by several simulations.

• 전력전자학회논문지
• /
• 제26권1호
• /
• pp.16-24
• /
• 2021

Solar array simulator (SAS) is essential equipment in testing and evaluating the power processing performance of a power conditioning system. However, the nonlinearity in the current(I)-voltage(V) characteristic makes the control loop design of SAS a challenging task. Conventionally, only the inner loop is usually considered in the control design approach. However, this study proves that the reference generation loop also interacts with the inner loop and plays a key role in the overall performance of the SAS. In this paper, the performance of voltage-mode control and impedance control, which are two of the most popular architectures for the SAS system, are reviewed and compared by multi-loop analysis.

• 대한교통학회지
• /
• 제20권2호
• /
• pp.149-159
• /
• 2002

다이아몬드 인터체인지에서 사용되는 두 가지 유형의 3현시 신호 체계의 운영결과를 다양한 교통상황 하에서 분석하였다. 본 연구를 수행하기 위하여 Hardware-in-the-loop 장치를 CORSIM 프로그램과 연결하여 사용하였으며, 운영결과는 평균지체와 총 정지수의 두 가지 효과척도를 사용하여 평가하였다. 평가결과 두 가지 3현시 신호 체계는 평균적으로 평균지체에 관해서는 동일한 결과를 나타내었으나 총 정지수는 다른 결과를 나타내었다. 또한 평균지체는 교통패턴과 인터체인지 거리에 따라 큰 영향을 받는 것으로 파악되었다. 총 정지수는 인터체인지 거리가 증가함에 따라 감소되었고, 두 가지 3현시 신호체계의 운영효과를 비교 평가할 수 있는 척도로 평가되었다. 그리고 Hardware-in-the-loop 장치를 결합하여 현재 시뮬레이션 기술의 적용영역을 확장할 수 있음을 구현하여 예시하였다.

• 한국정밀공학회지
• /
• 제14권11호
• /
• pp.102-109
• /
• 1997

A two-degree-of freedom (TDF) $H_{\infty}$controller for a seeker scan loop is presented for the purpose of improving scanning performances. The perturbed plant model is characterized via the normalized coprime factorization. The TDF $H_{\infty}$controller is designed based on the loop shaping design procedure and model matching approach, and its performances are evaluated and compared with those of a previous work. It is demonstrated that the proposed TDF $H_{\infty}$controller is more effective to the control of the seeker scan loop than the previous controller.oller.

• Journal of Power Electronics
• /
• 제11권2호
• /
• pp.156-162
• /
• 2011

The control loop time delay caused by sampling, the zero-order-holder effect and calculations is inevitable in the digital control of dc-dc switching converters. The time delay will limit the bandwidth of the control loop and therefore degrade the transient performance of digital systems. In this paper, the quantization time delay effects with different time delay values based on a generic second-order system are analyzed. The conclusion that the bandwidth of digital control is reduced by about 20% with a one cycle delay and by 50% with two cycles of delay in comparison with no time delay is obtained. To compensate the time delay and to increase the control loop bandwidth, a duty ratio predictive control scheme based on linear extrapolation is proposed. The compensation effect and a comparison of the load variation transient response characteristics with analogy control, conventional digital control and duty ratio predictive control with different time delay values are performed on a point-of-load Buck converter by simulations and experiments. It is shown that, using the proposed technique, the control loop bandwidth can be increased by 50% for a one cycle delay and 48.2% for two cycles of delay when compared to conventional digital control. Simulations and experimental results prove the validity of the conclusion of the quantization effects of the time delay and the proposed control scheme.

• 한국태양에너지학회 논문집
• /
• 제32권spc3호
• /
• pp.245-254
• /
• 2012

In photovoltaic system, the characteristics of photovoltaic module such as open circuit voltage and short circuit current will be changed because of cell temperature and solar radiation. Therefore, the boost converter of a PV system connects between the output of photovoltaic system and DC link capacitor of grid connected inverter as controlling duty ratio for maximum power point tracking(MPPT). This paper shows the dynamic characteristics of the boost converter by comparing single-loop and two-loop control algorithm using both analog and digital control. Both proposed compensation methods have been verified with computer simulation to demonstrate the validity of the proposed control schemes.