In order to improve the reliability of Switched Reluctance drive system, this paper presents a new control method to reduce the capacitance value of DC bus. Firstly, based on the equivalent mathematical model of the electrolytic capacitor, the capacitance value of the DC bus is estimated at the fixed frequency. Three methods are proposed to reduce the capacitance of the bus, and the mathematical relationship between the maximum value of the DC link current and the minimum capacitance value is established. A switching cycle is divided into two sections: the commutation region and the non-commutation region. The switching modes in different regions are analyzed, and the feasibility of the method is verified by simulation. In the end, the traditional control strategy and bus peak current control strategy are compared. Research results show that : BPC can reduce the capacitance value of 60% without affecting the efficiency of the system.