• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.151-152
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• 2011

This paper describes a cross-regulation characteristics of a multi-output LLC resonant converter widely used in consumer electronics. The output characteristics of the multi-output LLC converter is derived from the assumption that the current and voltage to flow through the resonant network is sinusoidal and the duty loss is investigated. The simulation results are provided to verify the theoretic results.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.2
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• pp.94-97
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• 2007

The desin and implementation of a CMOS analog integrated circuit that provides dual-mode modulations, PWM for active clamp reset converter and PFM for LLC resonant converter, is described. The proposed controller is capable of implementing programmable soft start and current-mode control with compensating ramp for PWM and frequency shifting soft start for PFM. Also it provides delay time for both modes. PWM mode is implemented by active clamp reset converter and PFM mode is implemented by LLC resonant convereter, respectively. The chip is fabricated using the 0.6um high voltage CMOS process.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.365-366
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• 2017

LLC resonant DC-DC converter is widely used in many kinds of applications such as battery energy storage systems, wireless power transfer and high voltage power supply. It is because of characteristics like high efficiency, power density, isolation, wide power level and stability enhancement at high switching frequency. Small signal modeling helps to design controller of the converter by approximating the behavior of nonlinear system with linear state equations. This paper presents comparison between small signal modeling analysis and experimental results of LLC resonant converter.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.825-829
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• 1993

By using the state plane approach, the steady state analysis and desing of a high frequency LLC-type series resonant converter and LLC-type parallel resonant converter operating in the continuous conduction mode is presented. When a LLC-type P.R.C operates above resonant frequency, the switching transitor can be turn off at zero voltage. A set of characteristic frequency are plotted from which desing parameters can be obtained.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.15-16
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• 2016

This paper proposes an isolated DCDC converter that consists of unregulated LLC resonant converter and non-isolated synchronous buck converter for battery charger of energy storage systems application. The unregulated converter operates as transformer with fixed duty ratio and switching frequency. The synchronous buck converter is installed in the output of the LLC resonant converter. And the converter charges and discharges the battery by controlling a current of battery. The proposed converter can get the high efficiency by separating function. This paper explains design of an unregulated converter and synchronous converter.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.4
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• pp.294-302
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• 2019

A capacitor common connected LLC resonant converter with auxiliary switches for a wide output voltage control range is presented in this paper. The proposed converter can be controlled in two ways to achieve a wide output voltage control range of Vo-3Vo. The first control method is performed through pulse width modulation of the auxiliary switches and primary switching devices. The second control method is conducted through frequency modulation of the primary switching devices configured to operate in full-bridge switching modes, when the auxiliary switches are turned off. The feasibility of the proposed converter is verified by the experimental results of a 5 kW prototype.

• Journal of the Korea Convergence Society
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• v.8 no.11
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• pp.313-319
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• 2017

In this paper, we present a design technique that miniaturises the DC-DC converter, a key component in the electric vehicle system, using the advanced material (Ga-N HEMT) in the LLC resonant converter and freely changes the resonant frequency. This design is also proposed to improve the efficiency and temperature characteristics by adding SR Topology in the secondary side output during the operation of power supply. In this experiment, as a consequence of the constructed circuit with the operation of high switching frequency of 200 kHz, the size of LLC and PFC was able to be minimised by 40[%]. Thus, the characteristics of operating temperature demonstrated $60-65^{\circ}C$ without a heat sink, when the temperature was measured at 250W (12V/20A). The features were all due to the advantages of the change of switching frequency, switching circuits implementation, and the maximisation of switching frequency. Based on these design results, we would like to implement more than 1 [kW].

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.6
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• pp.453-460
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• 2008

This paper proposes a new multi-output LLC resonant converter by using single control IC, which has the tight-regulated dual output voltage without additional power devices and controller. The proposed converter has master and slave outputs, of which regulations are achieved by the PWM(pulse width modulation) and PFM(pulse frequency modulation), respectively. Different from the conventional dual-output LLC resonant converter, the proposed converter has no additional post-regulators like a boost converter. Therefore, it features a low cost, small size, and high efficiency. To confirm the validity and prove the superiority of proposed converter, simulated and experimental results on a 50" FHD PDP power set prototype are presented.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.6
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• pp.438-444
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• 2019

In this paper, bidirectional LLC resonant DC/DC converters with the primary auxiliary windings in transformers of resonant circuits are proposed. Although the resonant capacitors are used on both the primary and secondary sides, regardless of the direction of power flow, the main feature of the proposed converters exhibits high gain characteristics without any mutual coupling between the resonant capacitors. For one of the proposed converters, an investigation of the operating characteristics in each mode has been carried out. A prototype of a 3.3 kW bidirectional LLC resonant converter for interfacing 750 V DC buses has been built and tested to verify the validity and applicability of the proposed converter.

• Journal of Power Electronics
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• v.14 no.1
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• pp.40-47
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• 2014

An average current mode control scheme that consistently offers good dynamic performance for LLC series resonant DC-to-DC converters irrespective of the changes in the operational conditions is presented in this paper. The proposed control scheme employs current feedback from the resonant tank circuit through an integrator-type compensation amplifier to improve the dynamic performance and enhance the noise immunity and reliability of the feedback controller. Design guidelines are provided for both current feedback and voltage feedback compensation. The performance of the new control scheme is demonstrated through an experimental 150 W converter operating with 340 V to 390 V input voltage to provide a 24 V output voltage.