This paper proposes two new open-circuit fault detection methods suitable for the diagnosis of power electronics converters. The faulty semiconductor devices are identified using conducted and radiated electromagnetic signatures of the dc bus through nonintrusive measurements. The first method uses a low-cost electromagnetic interference filter to collect the common-mode emissions signature. The second one utilizes an external antenna to collect the emitted near-field signature. Both methods are tested on a three-level neutral point clamped inverter (NPC) inverter with the aim to identify the clamping diodes open-circuit faults. Indeed, each open-circuit fault affects the common-mode emission signature in the time-domain, while the fast Fourier transform of the emitted near-field showed substantial reduction of spectrum amplitude at a specific radio frequency range and the appearance of a new spectral rail. The effectiveness of these two methods has been tested through numerical simulations and validated by experimental results which confirmed its high performance in detecting single as well as multiple open-circuit faults for three-level NPC inverter.

This paper proposes a real-time DSP- and FPGA-based implementation method of a space vector modulation (SVM) algorithm for an indirect matrix converter (IMC). Therefore, low-cost and compact control platform is built using a 32-bit fixed-point DSP (TMS320F2812) operating at 150 MHz and a SPARTAN 3E FPGA operating at 50 MHz. The method consists in using the event-manager modules of the DSP to build specified pulses at its PWM output peripherals, which are fed to the digital input ports of a FPGA. Moreover, a simple logical processing and delay times are thereafter implemented in the FPGA so as to synthesize the suitable gate pulse patterns for the semiconductor-controlled devices. It is shown that the proposed implementation method enables high switching frequency operation with high pulse resolution as well as a negligible propagation time for the generation of the gating pulses. Experimental results from an IMC prototype confirm the practical feasibility of the proposed technique.

This paper presents a new control method for indirect matrix converter operating under unbalanced grid voltages. The proposed method aims to achieve balanced output voltages as well as a near unity input power factor operation. First, an opportune reference current accurately generated, and a proportional integral resonant controller are designed in a dq reference frame that is synchronized with the positive sequence of the grid voltages so as to achieve a perfect tracking of input reactive power reference. Then, a real-time estimator of the virtual dc-link voltage is developed with the aim to provide balanced output voltages; therefore, an almost constant active power free of low frequency ripple is supplied from the grid. Experimental results are presented to verify the feasibility and effectiveness of the proposed control method.

This paper introduces an enhanced commutation method applied to the indirect matrix converter topology. It is based on the detection of the load current polarity so as to cancel the turn-on delay times of the load-side converter's switches. The proposed method allows the grid-side converter devices to commutate at zero current with larger time interval widths provided for this safe commutation. Moreover, it has been shown through experimental results, carried out on a laboratory prototype of the matrix converter, that a substantial improvement of line current total harmonic distortion is achieved.

The quasi-type-l phase-locked loop (QT1-PLL) is a grid synchronization technique that has become very popular in recent years thanks to its attractive performance such as easy implementation, fast dynamic response, and good accuracy in steady-state operation. However, it is still vulnerable to operation under harmonically distorted grid voltages with frequency drift. This paper proposes a novel QT1-PLL based synchronization algorithm that makes an appropriate combination of two filters’ types: an in-loop third-order moving average filter (MAF) with a reduced window width, and a simplified second-order fast delayed signal cancellation (FDSC) based prefiltering stage. The proposed PLL is named third-order MAF based QT1-PLL (TQT1-PLL). Though both TQT1-PLL's filters do not need any adaptive algorithm, it is able to reject non-triplen odd-harmonics and the fundamental frequency negative sequence (FFNS) even under grid frequency drift. Its correct operation is confirmed through numerical simulations and real-time implementation on a digital signal processor (DSP). Moreover, the obtained results confirm its ability to reduce the ripple in the estimated frequency and phase under distorted grid voltages and off-nominal frequency operation. Authors show also through an analytical development that the topology of the proposed TQT1-PLL can be extended to enable the rejection of the DC-offset.

Maximum power point tracking (MPPT) controllers are a key element in photovoltaic (PV) conversion systems since they allow extracting the maximum power from PV generators. Metaheuristic algorithms such as the particle swarm optimisation (PSO) are nowadays widely adopted and have shown their superiority to many other techniques. However, conventional PSO (CPSO) algorithms still suffer from the problem of long convergence time when the range of the search area is large. To overcome this issue, this study proposes a fast fuzzy logic PSO (FL‐PSO) based MPPT controller for PV systems. Unlike CPSO algorithm running with constant key parameters (inertia weight and acceleration coefficients), the proposed method includes a fuzzy inference system that dynamically adjusts these parameters. The effectiveness and rapidity of the proposed FL‐PSO algorithm is validated trough numerical simulations and experimental tests. The obtained results show the superiority of the proposal as compared to CPSO, Jaya and hill climbing algorithms even under partial shading conditions and abrupt change of solar irradiation.