Offline generation of Selective Harmonic Control PWM (SHC-PWM) solutions for Active Power Filters (APFs) presents a significant computational burden, particularly for extensive operating ranges. This paper proposes an efficient hybrid algorithm combining Differential Evolution (DE) and Nelder-Mead (NM) within a hierarchical framework to drastically accelerate this offline computation. The proposed method minimizes computationally intensive global optimization by adaptively employing fast local search, initialized with previously computed solutions, achieving smooth parameter variations. Achieving speedups greater than 100x compared to other hybrid methods, the algorithm successfully generated millions of unique SHC-PWM solutions averaging 0.07 seconds per point using a standard Intel Core Laptop. APF simulations using the generated data validated effective compensation for controlled current harmonics greater than 99.5%. This work enables the practical generation of large datasets required for advanced SHC-PWM strategies.

Modular Multilevel Cascade Converter (MMCC) have gained wide-spread acceptance in high voltage converter applications. As they require a high amount of capacitors whose voltages must be known for the control of the MMCC, many voltage sensors are needed. This paper proposes the application and the efficient implementation of fixed-point recurrent neural network (fpRNN) based observers for cell voltage estimation of chopper and bridge cells. The proposed observers are capable of learning from data to adjust the estimation model despite its intrinsic nonlinear behavior and unmodeled parasitic effects. The performance of the observer is validated against high-fidelity PLECS simulations. Moreover, the achievable estimation accuracy of different fpRNN observer implementations is compared depending on the utilized fixed-point number format.

Back-To-Back Modular Multilevel Converter (BTB MMC) was proposed as an attractive alternative for medium-voltage drive application to decrease the inherent problem of high floating capacitor voltage fluctuations produced at low frequency machine operation. Recently the variation of DC-Link reference between the MMC and a control strategy based in control the machine side MMC as a current source was introduced to decrease the mitigation variables using during low frequency operation. However, it does not solve the problem to obtain the minimal capacitor voltage fluctuation during the entire machine operation. This paper propose a new method to obtain the minimum capacitor voltage fluctuation of the MMC modules during the entire machine operation range including an additional AC signal between the system common link. The proposed control strategy and overall performance of the system are verified by computational simulation.

In this work a dynamic control of the dc-link voltage in a hybrid Back-to-Back (BtB) Modular Multilevel Converter for medium-voltage drive applications is presented. The proposed control scheme relates the speed of the machine with the dc-link voltage magnitude to reduce the large circulating currents and common-mode voltage of the converter when the machine operates at low speed. Simulation results, performed in the software PLECS, validate the model of the BtB converter and the proposed control scheme, reducing circulating currents and common mode voltage in almost 70% and 60% respectively, when the machine operates at very low speed.

Phase-Shifted Modulation (PSM) applied to multilevel converters is an effective method for reducing the output THD. In this paper, a new unipolar PSM method is proposed to control internal circulating current of a high-current low-voltage power converter, composed of parallel connected H- Bridges. The proposed method reduces the H-bridge currents distortions and the power losses of the overall converter. Simulation results comparing the standard unipolar modulation with the proposed unipolar modulation technique are performed to demonstrate its effectiveness.