Disturbance Observer-Based Control of a Dual-Output LLC Converter for Solid-State Lighting Applications

Abstract

Abstract-Feedback sensor isolation is often an expensive necessity in power converters, for reasons of safety and electromagnetic compatibility. A disturbance observer-based control strategy for a dual-output resonant converter is proposed to overcome this problem. Current control of two LED loads is achieved through estimation rather than measurement. Robustness against temperature changes, which have significant impact on the behaviour of the LEDs, is achieved through estimation of offsets in the forward voltages of the LED-strings. The power converter and LEDs are modelled accurately to obtain a good estimation accuracy. The whole implementation is steered towards a low cost solution.

Design Methodology of Tightly Regulated Dual-Output LLC Resonant Converter Using PFM-APWM Hybrid Control Method

“…The dual-output LLC resonant converter has the half-bridge structure of a primary inverting stage, a single transformer, and two output channels with diode rectifiers, as shown in Figure 1. to regulate multiple output voltages [25,26]. In addition, the SSPR has been used to achieve tight output voltage regulation for the LLC resonant converter [27][28][29][30].…”

“…Second, the magnetizing inductance is designed by considering the resonant frequency, the input voltage, and the parasitic capacitance of the MOSFETs, which was derived in (12). Third, the resonant inductance and capacitance ratio can be designed using (26). From the loss analysis, the required maximum voltage gain ratio can be calculated using (21), and (25).…”

“…Step 3: The required maximum voltage gain ratio is 1.31 and 0.64, which can be calculated with (21), and (25). The resonant inductance and capacitance can be calculated with (26), which are 70 µH and 30 nF. Therefore, the design example shows resonant impedance and magnetizing inductance to achieve ZVS for the entire load range, which can compensate all voltage errors of all the outputs using the hybrid control algorithm.…”

“…In terms of topology, the LLC resonant converter is attractive for several applications, because it has soft switching capability and a small number of resonant components [21][22][23][24]. In previous research of the multiple output LLC resonant converter, the cross regulation technique has been used to regulate multiple output voltages [25,26]. In addition, the SSPR has been used to achieve tight output voltage regulation for the LLC resonant converter [27][28][29][30].…”

Active Vibration Control of the Flexible Rotor in High Energy Density Magnetically Suspended Motor With Mode Separation Method

“…This issue relates to the optimal control method such as linear quadratic (LQ)/LQ Gaussian (LQG) control. LQG controller has been applied in various engineering systems such as power converter system [24][25][26], atomic force microscope [27], and wind turbine [28]. The authors in Ref.…”