• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.255-259
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• 2015

We have proposed and experimentally verified a pulse-width modulation (PWM) generator which directly generated a PWM signal in the optical domain. Output waveforms were clear at the repetition rate of 16 MHz; the duty cycle (DC) was from 14.7% to 72.1%; and the DC-control resolution was about 4.399%/dB. The PWM generator' operation principle is based on the injection-locking property of a single-mode Fabry-$P{\acute{e}}rot$ laser diode (SMFP-LD). The SMFP-LD, which has a self-locked mode wavelength at ${\lambda}_{PWM}$, was used to detect the power of the injection-locking signal (optical analog input). If the analog input power is high, the SMFP-LD is locked to the wavelength of the input signal ${\lambda}_a$ and there is no output after an optical bandpass filter (OBF). If the analog input power is low, the SMFP-LD is unlocked and there is output signal at ${\lambda}_{PWM}$ after the OBF. Thus, the SMFP-LD plus the OBF provide digital output for an analog input. The DC of the output PWM signal can be controlled by tuning the power of the analog input.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.179-181
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• 1998

In this paper, one chip PWM pattern generator which eliminates time delay of computations and improves utilization factor of voltage is proposed. Both amplitude of sinusoidal signal and triangular signal are directly controlled. Thus, time delay of computations can be eliminated, and it is possible to track accurately instantaneous current for a sudden change of load with microprocessor 80C196KC. In addition, setting dead-time is also possible for wide range. From experimental work with inverter system for driving induction motor, the validity of proposed one chip PWM pattern generator is verified.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.761-768
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• 2018

In this paper, the performance analysis of a control topology based on the direct output power control (DPC) for robust and inexpensive permanent magnet-assisted synchronous reluctance generator (PMa-SynRG) system is presented. The PMa-SynRG might be coupled to an internal combustion engine running at variable speed. A three-phase PWM rectifier rectifies the generator output and supplies the dc link. A single-phase PWM inverter supplies constant ac voltage at constant frequency to the grid. The overall control algorithm is implemented on a TMS320F2812 digital signal processor board. Simulations results and experimental results verify the operation of the proposed system.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.821-824
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• 2005

This paper presents a technique to evaluate torque and speed characteristics of induction motor with the Dynamometer. The simple Dynamometer controlled via microcontroller and displayed by computer. The Microcontroller generates the PWM (Pulse Width Modulation) signal and control the duty cycle of signal for control braking level. The Buck converter is a braking unit which uses IGBT as switch in circuit. The output current of the Buck converter and output voltage of tacho generator are converted to digital signals and analyzed by microcontroller. The signals are then sent to computer for displaying torque and speed responds independent on the braking time. The test results of the Dynamometer in this research can coreectly predict the torque and speed response under reasonable tests. Moreover, this Dynamometer is easy and inexpensive to make.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.513-518
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• 2016

The piezoelectric actuating device is known for its large power density and simple structure. It can generate a larger force than a conventional actuator and has also wide bandwidth with fast response in a compact size. To control the piezoelectric actuator, we need an analog signal conditioning circuit as well as digital microcontrollers. Conventional microcontrollers are not equipped with an analog part and need digital-to-analog converters, which makes the system bulky compared with the small size of piezoelectric devices. To overcome these weaknesses, we are developing a single-chip controller that can handle analog and digital signals simultaneously using mixed-signal FPGA technology. This gives more flexibility than traditional fixed-function microcontrollers, and the control speed can be increased greatly due to the parallel processing characteristics of the FPGA. In this paper, we developed a floating-point multiplier, PWM generator, 80-kHz power control loop, and 1-kHz position feedback control loop using a single mixed-signal FPGA. It takes only 50 ns for single floating-point multiplication. The PWM generator gives two outputs to control the charging and discharging of the high-voltage output capacitor. Through experimentation and simulation, it is demonstrated that the designed control loops work properly in a real environment.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.209-211
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• 1995

This paper is concerned with High Frequency, High Voltage Generator for X-ray using zero-voltage soft-switching PWM DC-DC high-power converter by Resonant method, which makes the most of the parastic LC parameters of high-voltage transformer link, for diagnostic X-ray power generator. The converter circuit basically utilizes phase-shift pulse width modulated series Resonant full-bridge PWM DC-DC high-power converter operating at a constant frequency;25kHz. The converter output regulation is digitally controlled using DSP (Digital Signal Processor) for obtaining a fast rising time and adjust output voltage within a wide load range.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1207-1212
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• 2011

This paper presents a study on the DSP(Digital Signal Processor) controller for the PBW(power-by-wire) system using BLDC(Brushless Direct Current) servo motor pump. The PBW hydraulic actuator was realized with hydraulic pump driven by BLDC servo motor, hydraulic cylinder and controller. This PBW system needs speed control of servo motor for linear thrust action of hydraulic cylinder. This paper implements a servo controller with vector control algorithm and MIN-MAX PWM technique. As CPU of a controller, TMS320F2812 DSP was adopted because it has PWM waveform generator, A/D converter, SPI(Serial Peripheral Interface) port and many input/output port etc.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.829-833
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• 2007

In this paper, the RCF method is applied to analyze small signal stability of power systems including GTO controlled parallel FACTS equipments such as STATCOM. To apply the RCF method in power system small signal stability problems, state transition equations of generator, controllers and STATCOM are presented. In eigenvalue analysis of power systems, STATCOM is modelled as the equivalents voltage source model and the PWM switching circuit model. As a result of simulation, the RCF method is very powerful to calculate the oscillation modes exactly after the switching operations, and useful to analyze the small signal stability of power systems with periodically operated switching devices such as STATCOM.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.225-227
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• 2008

This paper deals with the implementation on a Field Programmable Gate Array (FPGA) of PWM switching patterns for a voltage multilevel inverter. The reference data in main microcontroller is transmitted to the FPGA through 16 general purpose I/O ports. Herein, three-phase reference voltage signals are addressed by the last 2-bit (bit 15-14) and their data are assigned in remaining 14-bit, respectively. The carrier signals are created by 16-bit counter in up-down counting mode inside FPGA according to desirable topology. Each reference signal is compared with all carrier signals to generate corresponding PWM switching patterns for control of the multilevel inverter. Useful advantages of this scheme are easy implementation, simple software control and flexibility in adaptation to produce many PWM signals. Some simulations and experiments are carried out to validate the proposed method.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.4
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• pp.288-295
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• 2010

Multi-level inverters have drawn much of attention in recent years because it can meet the demand of high power applications and good power quality associated with reduced harmonic distortion. As the number of voltage level increases, field programmable gate arrays (FPGAs) are suitable for the implementation of multi-level modulation algorithm. This paper proposes the implementation method for generating PWM pulses at the three phase diode clamped five-level inverter using FPGA. The strategy for communicating stably the data of three-phase reference voltages between the DSP and FPGA is suggested. The techniques for generating PWM signals based on a multi-carrier modulation method are carried out through the experiments with 32-bit DSP and Cyclone-III FPGA.