This paper presents a new application of power and voltage balance control schemes for the cascaded H-bridge multilevel inverter (CHMI)-based solid-state transformer (SST) topology. To reduce load on the controller and simplify modulation algorithm, a master-slave control (MSC) strategy is designed for the dual active bridge (DAB) stage. The master controller executes all control and modulation calculations, and the slave controllers manage only device switching and protection. Due to the inherent power and dc-link voltage unbalance in cascaded H-bridge-based SST, this paper presents a compensation strategy based on three-phase dq decoupled current controller. An optimum zero-sequence component is injected in the modulation scheme so that the three-phase grid currents are balanced. Furthermore, to tightly regulate the output voltage of all the DAB modules to target value, a dynamic reference voltage method is also implemented. With this proposed control method, the three-phase grid currents and dc-link voltage in each module can be simultaneously balanced. Finally, simulation and experimental results are presented to validate the performance of the controller and its application to microgrid SST.

This paper presents a maximum torque per ampere (MTPA) control method for interior permanent magnet synchronous motor (IPMSM) drives. The proposed method employs a variable-equivalent-parameter MTPA control law to calculate the MTPA current references. Different from conventional MTPA control laws, this novel MTPA control law equivalently considers both the influence of the motor parameter values as well as the influence of the derivatives of motor parameters with respect to d- and q-axis currents on the MTPA control. Therefore, the proposed method can achieve accurate MTPA control under different load conditions. In addition, this novel MTPA control law avoids the computation of derivatives of motor parameters and the complicated computations that exist in conventional MTPA control laws. Thus, the proposed method can provide the MTPA current references easily and in real time, allowing for fast MTPA control to be achieved. Both simulation and experimental results confirm the effectiveness of the proposed MTPA method.

This paper presents a maximum torque per ampere (MTPA) control scheme for interior permanent magnet synchronous motor (IPMSM) drives. In this scheme, an enhanced signal injection technique is responsible for correcting the MTPA reference deviation due to motor parameter variations, and a derived MTPA control law is responsible for generating constant-parameter model-based MTPA current references to enhance the dynamic performance of the MTPA operation. Unlike previous signal injection techniques, the enhanced injection technique directly injects signals into the d- and q-axis currents and extracts the MTPA indicator from the reconstructed dc-link current. Hence, this enhanced injection technique avoids any transformations associated with polar coordinates, and it does not depend on a dc-link voltage sensor or a high-resolution speed sensor. The derived MTPA control law, unlike conventional MTPA control laws, can be realized in real time without mathematical approximations or lookup tables. With the combination of the enhanced signal injection technique and the derived MTPA control law, the proposed MTPA scheme can achieve an accurate and fast MTPA operation. Simulation and experimental results confirm the validity of the proposed MTPA scheme.

The essential feature of DC-DC converter for fuel cell vehicle is to ensure the higher voltage gain to meet out the higher DC link voltage demand, continuous input current to improve the life span of fuel cell, presence of common grounding to avoid electromagnetic interference issue and lower voltage stress with reduced components. This paper presents a high voltage gain DC-DC converter by combining the switched capacitor and quasi switched boost networks modules. The proposed high voltage gain converter provides the continuous input current, lower voltage stress, utilizes fewer number of elements and common grounding feature. The operating characteristics, steady state analysis both in continuous current mode (CCM) and discontinuous current mode (DCM), comparative analysis with contemporary converters are discussed. The theoretical claimed analysis is validated by the simulation and experimental study. The proposed converter is operated for 200 W output power rating and tested for providing the voltage gain in the range of 5-8 times the input voltage gain by varying the input voltage from 25 V-40 V. The efficiency of the proposed converter is also reported for different output power rating which is in the range 91.3%-93.7%.

In renewable application, a compact high step up DC-DC converter is a prime requirement with continuous input current and lower voltage stress across the devices. In this paper, a high gain DC-DC converter is proposed which utilizes the concept of switched inductor/capacitor and dual switch. The proposed converter has reduced conduction losses, reduced component count, low voltage stress across the devices and therefore compact in size. In addition, the proposed converter has lower inductor current ripple which is suitable for renewable integration. The operation and steady state analysis of the converter is done in continuous current mode. The proposed converter voltage and current stress along with the losses are calculated analytically. Moreover, a comparative analysis is presented to prove the effectiveness of the proposedconverter. Finally, an experimental set up is designed and tested for two distinct power ratings.

In this article, an isolated bidirectional dc-dc converter with an integrated cascade structure is proposed for a centralized charge equalization system. Compared with existing architectures, the proposed converter structure is equivalent to the integration of polarity switches and a bidirectional dc-dc converter. Equalization of cells with different voltage polarities can be realized by controlling the working state of the converter, which further improves the reliability and integration of the equalization system. The integrated cascade structure can not only increase the equalization current and make it work in a continuous state but also achieve a high voltage conversion ratio to improve the efficiency of the transformer. Theoretical derivations of the converter and the conditions of soft-switch implementation are analyzed in detail. Finally, equalization experiments on a 13-cell lithium-ion battery string are carried out, and a quantitative and comprehensive comparison of different centralized equalizer is conducted. The experimental and comparison results validate the superiorities of the proposed equalizer and demonstrate obvious performance enhancement over the conventional method.