For

$dq$

control strategies in single-phase pulse width modulation (PWM) converters

the

$\beta-\mathbf{axis}$

current must be created by imaginary axis current estimation (IACE) methods. The estimated error of the

$\beta-\mathbf{axis}$

current during the transient process causes

$d-q$

axis current loops to be incompletely decoupled

thereby affecting the dynamic performance of the current loop. The second-order generalized integrator (SOGI) method suffers from slow dynamic response. The fictive-axis emulation (FAE) method provides fast dynamic response but it is sensitive to circuit parameters. A reference-input (RI)-based IACE method is proposed to overcome the above shortcomings. According to the characteristic that the

$\beta-\mathbf{axis}$

current loop has no transient process

the

$\beta-\mathbf{axis}$

current is estimated by the

$d-q$

axis reference inputs. This is equivalent to introducing the

$\beta-\mathbf{axis}$

reference input as a feedforward term into the

$d-q$

axis current loop

so the parameter sensitivity problem is solve

d

and the parameter tuning is not needed. The proposed method can maintain good steady-state performance and significantly improve the dynamic performance of the current loop. Furthermore

it is straightforward and can be easily implemented in digital controllers. Comprehensive hardware-in-the-loop (HIL) experimental comparisons with the SOGI and FAE methods have been conducted to verify the correctness and effectiveness of the proposed RI-based IACE method.