Input-parallel output-series (IPOS)-based combined converter is usually used in the situation with low input voltage and high output voltage to satisfy the requirements in switch voltage stress reduction and power expansion. In such a system, the voltage balance of filter capacitor in the output side or current sharing in the input side usually used to guarantee the control performance of the conversion system. In this paper, a phase-shifted full bridge (PSFB)-based IPOS converter with modified connection of output filter circuit used for the wide variation of input voltage is proposed, which is beneficial to reduce ripple current of filter inductor significantly. A control scheme using the same phase shifting for the two different modules of this IPOS converter is detailedly investigated with both steady state and small signal model-based analysis, it manifests that special voltage balance and current sharing control scheme are not necessary for IPOS system under the common phase shifting control method. And the small signal transfer functions of this topology used for dual loop control system design are also developed. The simulation and experiment results are presented to validate the analysis and control scheme. INDEX TERMS Input-parallel output-series, combined converter, phase shifted full bridge, voltage balance.

A bidirectional integrated bus voltage conditioner (IBVC) for an isolated phase-shifted full bridge (PSFB) dc/dc converter is proposed to reduce the dc bus voltage oscillations in a cascaded power converter system, where a load converter is controlled tightly with high-control bandwidth. In the proposed method, unlike conventional dc bus voltage stabilization methods for which auxiliary switches are used, the multiplexing utilization of the full bridge switches at the primary side of a PSFB is adopted. In this paper, to improve the dc bus voltage stability, an equivalent virtual resistor is implemented by applying the duty cycle regulation for both legs of the PSFB. The effectiveness of the proposed method on the dc voltage stabilization is examined through simulations and experiments. The achieved results reveal that the dc bus voltage stability is significantly improved with the proposed method.INDEX TERMS Integrated DC bus voltage conditioner, switch multiplexing utilization, virtual resistor, cascaded power converter, DC bus voltage stability.

Since it has strong ability to realize a conversion to adapt to a wide variation of input voltage, the double-switch buck-boost (DSBB) converter is usually employed as a front-end converter in two-stage power converter systems, where conversion efficiency is always highly valued. Because there is only one switch in the Pulse Width Modulation (PWM) state in the buck or boost work mode, the combined control scheme was investigated for its advantages in inductor average current and conversion efficiency. However, in this method, the operation mode should be determined by additional logic according to the change of input voltage. Moreover, different control systems should be designed for different operation modes to guarantee dynamic control performance and smooth transition between different work modes. To address these issues, the linear active disturbance rejection control (LADRC) method is introduced to develop an inner current control loop in this paper. In this method, the model deviations in different work modes are considered as a generalized disturbance, and a unified current control plant can be derived for current controller design. Furthermore, the duty cycle limitations in practice are considered, an additional mode for transitional operation is produced, and the corresponding control scheme is also developed. Simulation and experimental test results are provided to validate the correctness and effectiveness of the proposed control scheme.

In traditional hybrid energy storage system (HESS), separated bidirectional dc/dc converter is usually used to interface energy storage system with dc bus. Though it has an advantage in flexibility of control system design using separated power converters, it results in more switches, auxiliary components, and cost for the whole system development. Particularly, since the energy storage system (ESS) designed for high dynamic compensation (e.g., supercapacitor) is mainly used to provide high-dynamic compensation in transient state process, the utilization rate of the corresponding interface dc/dc converter is relatively low. On the other hand, the dc bus voltage compensation performance will be discounted due to the inherent time delay for the current reference signal production of HESS with outer loop voltage control. In this paper, to address these two issues, an integrated topology of the hybrid energy storage system is proposed, and an improved control method that has the ability to enhance the control performance of HESS to compensate the dc bus voltage is developed too. The experimental test results are provided to validate the correctness and effectiveness of the proposed methods. INDEX TERMS Hybrid energy storage, multi-port converter, phase shifted full bridge, feedforward compensation.

The three-port converter (TPC) obtains major attention due to its power density and ability to dispose different electric powers flexibly. Since the control models of the TPC are derived from particular steady state work point through small signal modeling method, the model parameters usually be deviated from their normal values with the change of operation and load conditions. Furthermore, there are couplings and interactions in power delivery between different ports, which have a significant influence in the dynamic control performance of the system. In this paper, the H∞ mixed sensitivity method is employed to design robust controllers for a TPC control system. Simulation results are given to demonstrate the effectiveness of the proposed scheme, and experimental studies are conducted on a prototype circuit to further validate the developed method. Compared to a traditional PI controller, it shows that a mixed sensitivity based robust controller manifest balanced performance in model parameters changes attenuation and dynamic control performance.