Concerning about integration and high efficiency of the number of switches and the complexity of the drive circuits. So the number of switches should be as few as possible. By increasing switching frequency, the size of power inductor and filter capacitor can be significantly reduced. Switching losses and the effective operation range of duty cycle are two factors that restrict the increase of switching frequency. Literature [6] integrates same switch-units composed of diodes and MOSFETs of different converters, whereas literatures [7]-[9] insert specific switch-units into traditional dc-dc converters. Both the number of switches and passive components are decreased, but the switches work on hard switching condition. And the power transmission between three ports is in time division manner, hence duty cycle of switches is restricted. The topology proposed in [10] is derived from two cascade boost converters, and only two MOSFETs and two inductors are needed. The soft switching is achieved but the effective duty cycle of each switch is low. For satellite electrical power systems, a MPC is proposed in [11], which consists of unidirectional step-down converter and bidirectional PWM converter. There are two inductors and three MOSFETs but the switches suffer hard switching problem. In [12], auxiliary circuits contained coupled inductors and switches are required to achieve soft switching. However, the cost of components is increased and the power density is decreased. Moreover, the actual working conditions of the solar array should be evaluated in order to increase the response speed and the tracking accuracy of the MPPT algorithms and to cope with the problem of multipeak output power. At present, the most commonly used method is measuring short-circuit current and open-circuit voltage of the solar array from [13] and [14]. However, many of the PWM-based multiport converters like [4], [5], [10]-[12] need additional measuring circuit, which reduces the power density of the system. Bridge converters can be integrated with buck/boost converter by sharing bridge arm switches [15]-[18]. Bridge based MPCs, featuring soft switching and wide operation range, usually are partially isolated converters. To ensure the central symmetry of the voltage at the midpoint of the bridge arm, most bridge-based MPCs are of the full-bridge type. But for non-isolated converters, half-bridge is better. A bidirectional buck/boost converter and a half-bridge phase shift converter are