• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.914-915
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• 2008

Generally, inverter controller for UPS or renewable energy system have been used double loop PI controller, But it is hard to get controller gains for double loop controller because it is high order. Futhermore, to consider time specification is difficult too. This paper presents the way how to make double PI loop controller for inverter satisfied with time specification using CRA method and verify efficiency of it using Matlab and Psim.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.2
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• pp.116-127
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• 2003

In this paper, a new fully digital control method for UPS inverter, which is based on the double control loop such as the outer voltage control loop and inner current control loop, is proposed. In the proposed control system, overshoots and oscillations due to the computation time-delay are compensated by explicit incorporation of the time-delay in the current control loop transfer function. The inner current control loop is adopted by an Internal model controller The Internal model controller is designed to a second order deadbeat reference-to-output response which means that its response reaches the reference in two sampling time including computational time-delays. The outer voltage control loop employing P-Resonance controller is proposed. The resonance controller has an infinite gain at resonant frequency, and the resonant frequency is set to the fundamental frequency of the reference voltage in this paper. Thus the outer voltage control loop causes no steady state error as regard to both magnitude and phase. The effectiveness of the proposed control system has been verified by the simulation and experimental results respectively.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.6
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• pp.442-450
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• 2020

A small-signal modeling approach for a three-level boost (TLB) converter and a design methodology for a double-loop controller are proposed in this study. Conventional modeling of TLB converters involves three state variables. Moreover, TLB converters have two operation modes depending on the duty ratio. Consequently, complex mathematical calculations are required for controller design. This study proposes a simple system modeling method that uses two state variables, unlike previous methods that require three state variables. Analysis shows that the transfer functions of the two operation modes can be expressed as identical equations. This condition means that the linear feedback controller can be applied to all operational ranges, that is, for full duty ratios. The design method for a double-loop controller using a PI controller is presented in step-by-step sequences. Simulation and experimental verifications are conducted to verify the effectiveness of the small-signal analysis and control system design.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.561-568
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• 2003

There arc two ways in the output voltage control method in PWM inverters. One Is double loop voltage control composed of inner current control loop and outer voltage control loop.'rho other is single loop voltage control method composed of voltage control loop only. It's characteristics shows lower performance in case of high output impedance than double loop voltage control. However, in case of low output impedance, it shows good control performance in all load ranges than double loop voltage control. In this paper, the rule and the gain of single loop voltage control have been developed analytically and these were verified through computer simulation and experiment.

• Journal of Power Electronics
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• v.15 no.3
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• pp.695-701
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• 2015

Uninterruptible Power Supplies (UPSs) can be largely divided into the passive-standby, line-interactive and double-conversion methods. This paper proposes a double-conversion UPS with a low cost and high performance. This single phase UPS uses a single-loop robust voltage controller and 1-switch voltage doubler strategy PFC. The proposed UPS is composed of a single phase PFC, a half-bridge inverter, a battery charger and a battery discharger. Finally, the validity of proposed UPS was verified by various experimental tests.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.871-877
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• 2018

In this paper, we propose a triple nested PID control scheme for stable hovering of a quadrotor and propose a complementary filter based sensor fusion technique to improve the performance of attitude, altitude and velocity measurement. The triple nested controller has a structure in which a double nested attitude controller that has the angular velocity PD controller in inner loop and the angular PI controller in outer loop, is nested in a velocity control loop to enable stable hovering even in the case of disturbance. We also propose a sensor fusion technique by applying a complementary filter in order to reduce the noise and drift error included in the acceleration and gyro sensor and to measure the velocity by fusing image, gyro, and acceleration sensor. In order to verity the performance, we applied the proposed control and measurement scheme to hovering control of quadrotor.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1743_1744
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• 2009

In this paper, we propose a double network control approach for linear systems. Generally, there are two network control system structures: the direct structure and the hierarchical structure. Here, the hierarchical structure consists of a main controller and a remote controller. The network delay of the structure only appears in the closed loop between the main controller and the remote system. However, the delay can exist between the remote controller and the actuator. Therefore, we design the double network system with delays between the main controller and the remote system, and the remote controller and the actuator. Finally, we carry out simulations on the linear system to illustrate the effectiveness of the proposed control method.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.496-500
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• 2001

There are two ways in the output voltage control method in PWM inverter. One is the double loop voltage control composed of inner current control loop and outer voltage control loop. Because it shows fast response and low steady state error, utilized in many application. The Other is single loop voltage control method composed of voltage control loop only. It's characteristics shows lower performance in case of high output impedance than double loop voltage control. But in low output impedance, it shows good control performance in all load range than double loop control. In this paper, single loop voltage control rule and gain was developed analytically, and these were verified through computer simulation and experiment.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.1
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• pp.7-12
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• 2006

This paper proposes the new voltage event detection method using the weight factor of neural network and describes control system design for the DVR(Dynamic Voltage Restorer) consisted of a rectifier and series inverter applied to 22.9kV distribution system. As this method can express the fault level of each phase, we expect the proposed method can make up for disadvantage of synchronous detection method. Also, in this paper, the control system was designed using double deadbeat controller, As it has an inner current control loop and an outer voltage control loop, we can easily limit the current level during the transient intervals by using the current control loop. Simulation and experiment are performed to prove the analysis of the voltage event detection method and double deadbeat controller.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.1
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• pp.1-11
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• 2007

In this paper, a new fully digital control method for UPS inverter, which is based on the double control loop such as the outer voltage control loop and inner current control loop, is proposed. In the proposed control system, overshoots and oscillations due to the computation time-delay are compensated by explicit incorporation of the time-delay in the current control loop transfer function. The inner current control loop is adopted by an internal model controller. The internal model controller is designed to a second order deadbeat reference-to-output response which means that its response reaches the reference in two sampling time including computational time-delays. The outer voltage control loop employing P-Resonance controller is proposed. The resonance controller has an infinite gain at resonant frequency, and the resonant frequency is set to the fundamental frequency of the reference voltage in this paper. Thus the outer voltage control loop causes no steady state error as regard to both magnitude and phase. The effectiveness of the proposed control system has been verified by the simulation and experimental results respectively.