• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.28 no.3
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• pp.274-285
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• 1992

Among various Power converters, a variable voltage variable frequency (VVVF) three-phase PWM inverter is regarded as most promising power converter due to its capabilities, which permits the control of voltage, frequency and harmonic contents in a single power stage employing only on DC source. As a modulating technique of the PWM inverter, the regular sampling technique has rendered possible the on-line computation and generation of PWM control waveforms with a reasonably high switching frequencies. In this paper, microprocessor based three-phase regular samping PWM inverter with real-time control algorithm and control circuits for driving three phase AC motor has been developed. Harmocic components of PWM waveform were analized theoretically in terms of Bessel function series and then calculated by digital computer and observed with spectrum analyzer.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.1
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• pp.90-97
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• 2001

A high frequency resonant inverter consisting of iliree unit Half-Bridge serial resommt inverter used as power source of induction heatmg at high frequency is presented in this paper. As a output [Dwer control strategy, sequencial time-sharing gate contml methcd is applied. This methcd is TDM(Time Division Multiplexing), which is broadly used with digital and analog signals transmission in communication system 1be analysis of the proposed circuit is generally described by using the normalized pararmenters. Also, the principle of basic operating and the its characteristics are estimated by the parameters such as switching frequency, load resistance. Also, according to the calculated characteristics value, a method of the circuit design and operating characteristics of the inverter is proposed. This paper proves the validity of theoretical analysis through the Pspice. This proposed inverter show that it can be practically used in future as power source system for induction heating application, DC-DC converter etc. r etc.

• Proceedings of the IEEK Conference
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• 2004.06b
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• pp.399-402
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• 2004

This paper presents a system-on-chip prototype implementing a full integration for a portable digital audio system. The chip is composed of a audio processor block to implements audio decoding and voice compression or decompression software, a system control block including 8-bit MCU core and Memory Management Unit (MMU) a low power 16-bit ${\Sigma}{\Delta}$ CODEC, two DC-to-BC converter, and a flash memory controller. In order to support other audio algorithms except Mask ROM type's fixed codes, a novel 16-bit fixed-point DSP core with the program-download architecture is proposed. Funker, an efficient power management technique such as task-based clock management is implemented to reduce power consumption for portable application. The proposed chip has been fabricated with a 4 metal 0.25um CMOS technology and the chip area is about 7.1 mm ${\times}$ 7.1mm with 100mW power dissipation at 2.5V power supply.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.151-155
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• 2016

In this paper, we present the LED dimming control system by using ADPCM (Adaptive Differential Pulse Code Modulation). This ADPCM apparatus accurately controls the LED current with high resolution reducing the RFI (radio frequency interference) due to the spreading out of the harmonics of current of pulses. Additionally, this makes it easier to increase the accuracy of control operation. This study introduces to make a digitally controlled circuit for controlling LED with high-energy efficient by adopting pulse current to LED. The LED current drive system we designed are two systems, the digitally-controlled unit and analog switching mode power supply unit, can be developed separately. The simulation shows the sigma delta modulation of digital to analog converter's output when the input level is 0.7. From this simulation, the output is approached to accurately 0.15% to target value with 510 pulses.

• Journal of Power Electronics
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• v.16 no.3
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• pp.823-831
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• 2016

A high-efficiency method is proposed to suppress magnetic core imbalance in phase-shifted full-bridge (PSFB) converters. Compared with conventional solutions, such as controlling peak current mode (PCM) or adding DC blocking capacitance, the proposed method has several advantages, such as lower power loss and smaller size, because the additional current sensor or blocking capacitor is removed. A time domain model of the secondary side is built to analyze the relationship between transformer core imbalance and cathode voltage of secondary side rectifiers. An approximate control algorithm is designed to achieve asymmetric phase control, which reduces the effects of imbalance. A 60 V/15 A prototype is built to verify the proposed method. Experimental results show that the numerical difference of primary side peak currents between two adjacent cycles is suppressed from 2 A to approximately 0 A. Meanwhile, compared with the PCM solution, the efficiency of the PSFB converter is slightly improved from 93% to 93.2%.

• Journal of Ocean Engineering and Technology
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• v.8 no.1
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• pp.50-61
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• 1994

A 300 meter class ROV(CROV300) is composed of three parts : a surface unit, a tether cable and an underwater vehicle. The vehicle controller is based on two processors : an Intel 8097-16-bit one chip micro-processor and a Texas Instruments TMS320E25 digital signal processor. In this paper, the surface controller, the vehicle controller and peripheral devices interfaced with the processors are described. These controllers transmit/receive measured status data and control commands through RS422 serial communication. Depth, heading, trimming, camera tilting, and leakage signals are acquired through the embedded AD converters of the 8097. On the other hand, altitude of ROV and lbstacle avoidance signals are processed by the DSP processor and periodically fetched by the 8097. The processor is interfaced with a 4-channel 12-bit D/A converter to generate control signals for DC motors an dseveral transistors to handle the relays for on/off switching of external devices.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.5
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• pp.62-70
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• 2007

In this paper, the boost Power Factor Correction(PFC) technique for Direct Torque Control(DTC) of brushless DC motor drive in the constant torque region is implemented on a TMS320F2812DSP. Unlike conventional six-step PWM current control, by properly selecting the inverter voltage space vectors of the two-phase conduction mode from a simple look-up table at a predefined sampling time, the desired quasi-square wave current is obtained, therefore a much faster torque response is achieved compared to conventional current control. Furthermore, to eliminate the low-frequency torque oscillations caused by the non-ideal trapezoidal shape of the actual back-EMF waveform of the BLDC motor, a pre-stored back-EMF versus position look-up table is designed. The duty cycle of the boost converter is determined by a control algorithm based on the input voltage, output voltage which is the dc-link of the BLDC motor drive, and inductor current using average current control method with input voltage feed-forward compensation during each sampling period of the drive system. With the emergence of high-speed digital signal processors(DSPs), both PFC and simple DTC algorithms can be executed during a single sampling period of the BLDC motor drive. In the proposed method, since no PWM algorithm is required for DTC or BLDC motor drive, only one PWM output for the boost converter with 80 kHz switching frequency is used in a TMS320F2812 DSP. The validity and effectiveness of the proposed DTC of BLDC motor drive scheme with PFC are verified through the experimental results. The test results verify that the proposed PFC for DTC of BLDC motor drive improves power factor considerably from 0.77 to as close as 0.9997 with and without load conditions.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.4
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• pp.278-284
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• 2009

This paper presents a firing angle controller of a thyristor converter for DC power supply using PID controller with parallel data loop to improve the dynamic response. The proposed parallel data loop for firing angle controller of 3-phase semi-converter, generates pre-measured firing angle according to reference voltage and load current. With the approximated firing angle according to operating conditions, the output voltage can fast keep the reference value with small voltage error. And the PID controller compensates the output voltage error from the firing angle of parallel data loop. In order to reduce the sudden changing of the data from current ripple, a simple digital low pass filter is used to determine the output data. The proposed control scheme is verified by the experimental test of a practical 50[A] grade thyristor converter system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.1009-1012
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• 1995

This paper presents an example of the development of motor drives for machine tools. Machine tools need motor drives with high control precision and performance. We developed a motor drive system that meets these requirements. The converter, the one component of drive system, adopts modular structure and high DC-link voltage. The drive which consists rest part of drive system is developed based on TMS320C32 DSP and state-of-the-art circuit technology. In this paper each developed parts are described in terms of its structure, specification and features.

• Journal of Power Electronics
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• v.15 no.1
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• pp.190-201
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• 2015

This paper uses the switching function approach to present a simple state model of the Vienna-type rectifier. The approach introduces the relationship between the DC-link neutral point voltage and the AC side phase currents. A novel direct power control (DPC) strategy, which is based on the sliding mode control (SMC) for Vienna I rectifiers, is developed using the proposed power model in the stationary ${\alpha}-{\beta}$ reference frames. The SMC-based DPC methodology directly regulates instantaneous active and reactive powers without transforming to a synchronous rotating coordinate reference frame or a tracking phase angle of grid voltage. Moreover, the required rectifier control voltages are directly calculated by utilizing the non-linear SMC scheme. Theoretically, active and reactive power flows are controlled without ripple or cross coupling. Furthermore, the fixed-switching frequency is obtained by employing the simplified space vector modulation (SVM). SVM solves the complicated designing problem of the AC harmonic filter. The simplified SVM is based on the simplification of the space vector diagram of a three-level converter into that of a two-level converter. The dwelling time calculation and switching sequence selection are easily implemented like those in the conventional two-level rectifier. Replacing the current control loops with power control loops simplifies the system design and enhances the transient performance. The simulation models in MATLAB/Simulink and the digital signal processor-controlled 1.5 kW Vienna-type rectifier are used to verify the fast responses and robustness of the proposed control scheme.