According to the behavior characteristics of switching of the current generator during command current tracking，a constant frequency adaptive current control algorithm is developed using mathematical modeling.By recording the current tracking errors at the switch points in two adjacent cycles and on the principle of error sharing，the switch time of the next control cycle will be scheduled，and the adaptive pulse width modulation（PWM）signals of constant switch frequency generated，realizing rapid and accurate tracking of the command current.In order to examine the method's dynamic response performance under different transient conditions，a simulation model and prototype are built，the simulation and experimental results show the validity of the proposed algorithm in current tracking and control.