<p>This paper proposes an efficient control strategy for power and current balancing of half-bridge quadruple-CLLC (HB Q-CLLC) converters under unbalanced resonant tanks. This converter consists of a three-input and single-output structure, which requires crucial attention when the resonant tanks are unbalanced, particularly owing to parameter tolerances. Consequently, operation with variable or constant frequency modulations are not effective, resulting in unequal current and voltage stresses. Moreover, there is a low possibility of improving the modulation scheme in the HB structure. Therefore, the only way to improve the performance of this converter is by modification of its control scheme. It is found that both phase-shift and frequency controls should be applied to balance the input power and resonant inductor current simultaneously. In addition, the proposed method is simple and does not require hardware modifications. Experimental results have verified the effectiveness of the proposed control strategy with a 3-kW prototype. It is shown that the unbalance factor of input power and inductor current can be reduced from 40–48% to 1– 3% and from 30–60% to 2–6%, respectively.</p>