A Cuk Converter and Resonant LLC Converter Based E-Bike Charger for Wide Output Voltage Variations

In this article, an e-bike charging solution for two wheelers, is presented. This e-bike charger is realized by a Cuk converter followed by a
LLC
resonant converter with an improved power quality (PQ) input current indices. The pulsewidth modulated Cuk converter is operated in discontinuous conduction mode of its output side inductor, which leads to a voltage follower approach for input current shaping. Thus, the control loop is greatly simplified as it consists of a single voltage loop. The e-bike battery charging algorithm is implemented in variable frequency controlled HB
LLC
resonant converter followed by a diode rectification at its output stage. Furthermore, a
$\text{550}\;\text{W}$
, constant current/constant voltage charger with a maximum current rating of
$\text{10}\;\text{A}$
is developed to charge a
$20AH$
e-bike battery. A variable dc link reference voltage estimator is presented, which varies the dc link voltage and extends the output voltage range for charging e-bike battery of varying voltage rating from 42–
$\text{80}\;\text{V}$
. Moreover, a resonant frequency optimizer loop is also proposed, which reduces the turn-off losses during charging a deeply discharged battery. The behavior of this charger is exhaustively analyzed under steady state and transient conditions and the PQ at the input, is found to comply the international standard of
$IEC-61\,000-3-2$
.