Push–pull mode digital control for LLC series resonant dc‐to‐dc converters

Abstract

This study presents the design and performance evaluation of the digital control adapted to an LLC series resonant dc-to-dc converter operating with wide input and load variations. The proposed control design correctly incorporates the wide-varying power stage dynamics and variable small-signal gain of a digitally controlled oscillator, thereby offering satisfactory converter performance for all the operational conditions. The proposed digital controller adopts the push-pull mode control scheme, which executes the control action two times in one switching period, to minimise the time delay and enhance the performance. Using a 150 W experimental converter, the performance of the proposed push-pull mode digital control is demonstrated in comparison with that of the conventional complementary mode digital control, which performs the control action only once in one switching period.

Hybrid Dual-Loop Control for Current Regulation and Low-Frequency Ripple Rejection in Led Drivers

“…Assuming that the LED operates in its linear region, where the output light is directly proportional to i LED , the NM can be estimated from the FFT decomposition of the measured i LED . In this way, the NM is estimated by (17), wherein I LED is the LED average current, N is the number of harmonic components below 1250 Hz, andĩ m is the weighted LED current Fourier amplitude coefficient (|i m |) corresponding to frequency f m , which is given by (18).…”

“…Investigating the mechanism of ∆I O propagation in a digitally controlled LLC converter, in [16] the synchronous frequency dither is proposed to reduce the quantization error and attenuate ∆I O . Without compromise with ∆I O reduction, a three-pole two-zero (3P2Z) controller is designed in [17] and [18] to assure stability and good performance for the LLC converter over a wide operation range. Notwithstanding, all these approaches based on classical control theory are subjected to an unpredictable and deteriorated performance when the converter is exposed to a wide operating range, since linear controllers, such as Proportional-Integral (PI), IQR, PIR, 3P2Z, and PID are only valid near a particular operating point due to limitations of the employed small-signal models [19].…”

MHz zero‐voltage‐switched isolated resonant converter for wide‐output‐voltage application

“…3 b and the comparison is done between the proposed converter and traditional isolated Sepic MRC (Fig. 9 (d), [24]). It is concluded that the main difference between two converters is whether C s or C d participates in the resonance first.…”

“…The conduction loss of PRC stays relatively fixed as the load decreases so that the lightload efficiency of the converters suffers [19]. To improve the circuit performance, a variety of resonant converters have been derived from PRC and SRC [20][21][22][23][24][25]. Among them, LLC resonant converter attracts great interests of academia and industry, which involves adapter, LED lightning, electrical vehicle charger and many other applications.…”

Digital controller based on delta operator for high‐frequency DC–DC switching converters

“…The digitally controlled DC-DC switching converter has recently been attracting significant attention for its obvious advantages over its analogue counterpart, including sufficient flexibility to implement complex control strategies and algorithms, sufficient programmability to realise reconfigurable power systems, a faster design process, robustness to noise, and insensitivity to component parameter drift [1][2][3][4][5][6].…”