• Journal of Electrical Engineering and Technology
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• v.10 no.5
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• pp.1989-2000
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• 2015

In this paper, digital peak current mode control for single phase H-bridge inverters is developed and implemented. The digital peak current mode control is achieved by directly controlling the PWM signals by cycle-by-cycle current limitation. Unlike the DC-DC converter where the output voltage always remains in the positive region, the output of DC-AC inverter flips from positive to negative region continuously. Therefore, when the inverter operates in negative region, the control should be changed to valley current mode control. Thus, a novel control logic circuit is required for the function and need to be analyzed for the hardware to track the sinusoidal reference in both regions. The problem of sub-harmonic instability which is inherent with peak current mode control is also addressed, and then proposes the digital slope compensation in constant-sloped external ramp to suppress the oscillation. For unipolar PWM switching method, an adaptive slope compensation in digital manner is also proposed. In this paper, the operating principles and design guidelines of the proposed scheme are presented, along with the performance analysis and numerical simulation. Also, a 200W inverter hardware prototype has been implemented for experimental verification of the proposed controller scheme.

• Journal of Power Electronics
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• v.9 no.6
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• pp.903-910
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• 2009

In this paper, a digital average current mode control using diode current sensing technique is proposed. Although the conventional inductor current sensing technique is widely used, the sensed signal of the current is negative. As a result, it requires an additional circuit to be applied to general digital controller ICs. The proposed diode current sensing method not only minimizes the peripheral circuit around the digital IC but also consumes less power to sense current information than the inductor current sensing method. The feasibility of the proposed technique is verified by experiments using a 500W power factor correction (PFC) boost rectifier.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.970-973
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• 2003

Abstract An idea to redce the direct-path short circuit current of the CMOS digital integrated circuit is present. The sample circuit model of the CMOS digital circuit is the CMOS current-control digital output driver circuit, which are also suitable for the low voltage supply integrated circuits as the simple digital inverter, are present in this title. The circuit consists of active MOS load as the current control source, which construct from the saturated n-channel and p-channel MOSFET and the general CMOS inverter circuits. The saturated MOSFET bias can control the output current and the frequency response of the circuit. The experimental results show that lower short circuit current control can make the lower frequency response of the circuit.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.163-167
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• 2000

This paper presents the digital control of single-phase power factor correction(PFC) converter which has the variable gain according to the condition of inner control loop error. Generally the gain of inner current control loop in single-stage PFC converter has a constant magnitude. This has a bad influence on the power factor because current loop doesn't operate smoothly in the condition that input voltage is low In particular a digital controller has more time delay than an analog controller and degrades This drops the phase margin of the total digital PFC system,. It causes the problem that the gain of current control loop isn't increased enough. In addition the oscillation happens in the peak value of the input voltage open loop PFC system gain changes according to ac input voltage. These aspects make the design of the digital PFC controller difficult The digital PFC controller presented in this paper has a variable gain of current control loop according to input voltage. The 1kW converter was used to verify the efficiency of the digital PFC controller.

• Journal of Power Electronics
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• v.19 no.3
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• pp.613-624
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• 2019

Digital current control techniques are an attractive option for DC-DC converters. In this paper, a digital predictive peak current control algorithm is presented for buck converters that allows the inductor current to track the reference current in two switching cycles. This control algorithm predicts the inductor current in a future period by sampling the input voltage, output voltage and inductor current of the current period, which overcomes the problem of hardware periodic delay. Under the premise of ensuring the stability of the system, the response speed is greatly improved. A real-time parameter identification method is also proposed to obtain the precision coefficient of the control algorithm when the inductance is changed. The combination of the two algorithms achieves adaptive tracking of the peak inductor current. The performance of the proposed algorithms is verified using simulations and experimental results. In addition, its performance is compared with that of a conventional proportional-integral (PI) algorithm.

• Journal of Power Electronics
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• v.9 no.3
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• pp.410-417
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• 2009

This paper represents a design and implementation of a digital controller for a multi-phase synchronous buck converter (SBC) using a digital signal processor (DSP). The multi-phase SBC has generally been used for a voltage regulation module (VRM) of a microprocessor because of its high current handling capability at a low output voltage. The VRM requires high control performance of tight output regulation, high slew rate, and load sharing capability of multiple converters. In order to achieve these requirements, the design and implementation of a digital control system for a multi-phase SBC are presented in this paper. The digital PWM generation, current sensing, and voltage and current controller using a DSP TMS320F2812 are considered. The experimental results are provided to show the validity of the implemented digital control system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.183-187
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• 2008

This paper describes a power control scheme to improve the performance of a fuel cell battery hybrid power source for residential application. The proposed power control scheme includes a power control strategy to control the power flow of the fuel cell hybrid power system and a digital control technique for a front-end dc-dc converter of the fuel cell. The power control strategy enables the fuel cell to operate within the high efficiency region defined by the polarization curve and efficiency curve of the fuel cell. A dual boost converter with digital control is applied as a front-end dc-dc converter to control the fuel cell output power. The digital control technique of the converter employs a moving-average digital filter into its voltage feedback loop to cancel the low frequency harmonic current drawn from the fuel cell and then limits the fuel cell output current to a current limit using a predictive current limiter to keep the fuel cell operation within the high efficiency region as well as to minimize the fuel cell oxygen starvation.

• Journal of Power Electronics
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• v.12 no.4
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• pp.595-603
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• 2012

This paper presents a full digital control strategy for parallel connected modular inverter systems. Each modular inverter is a high frequency (HF) AC link inverter which is composed of a HF inverter and a HF transformer followed by a cycloconverter. To achieve equal sharing of the load current and to suppress the circulating currents among the modules, a three-loop control strategy, consisting of a common output voltage regulation (OVR) loop, individual circulating current suppression (CCS) loops and individual inner current tracking (ICT) loops, is proposed. The ICT loops are implemented with predictive current control from which high precision current tracking can be obtained. The effectiveness of the proposed control strategy is verified by simulation and experimental results from parallel connected two full-bridge HF AC link inverter modules.

• Journal of Power Electronics
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• v.7 no.3
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• pp.213-221
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• 2007

A digital state feedback control method for the current mode control of DC-DC converters is proposed in this paper. This approach can precisely achieve interleaved current sharing among the converter modules. As the controller design and system analysis are performed in the time domain, the proposed method can easily satisfy the required converter specification by using the pole placement technique. The digital state feedback controller in the continuous and discrete time domain is derived for the robust tracking control. For the verification of the proposed control scheme, a parallel module bi-directional converter in a prototype 42V/14V hybrid automotive power system, which is a design example in the continuous time domain, and a parallel module buck converter, which is a design example in the discrete time domain, are implemented using a TMS320F2812 digital signal processor (DSP).

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.54-60
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• 2020

A digital current control scheme using virtual d-q transformation for a boost single-phase power factor correction (PFC) converter is proposed. The use of virtual d-q transformation in single-phase power converters is known to improve current control performance. However, the conventional virtual d-q transformation-based digital current control scheme cannot be directly applied to the boost single-phase PFC converter because the current and average voltage waveforms of the inductor used in the converter are not sinusoidal. To cope with this problem, this study proposes a virtual sinusoidal signal generation method that converts the current and average voltage waveform of the inductor into a sinusoidal waveform synchronized with the grid. Simulation and experimental results are provided to show that the virtual d-q transformation-based digital current control is successfully applied to the boost single-phase PFC converter with the aid of the proposed virtual sinusoidal signal generation method.