Modulation of Indirect Matrix Converter under unbalanced source voltage condition

Abstract

This paper deals with the effects of unbalanced source voltages on Indirect Matrix Converter (IMC). A detailed theoretical analysis is presented for the harmonic content of input and output currents when unbalanced voltages are applied at IMC input. A control strategy is proposed, where the modulation index of inverter section of IMC is dynamically varied to eliminate the harmonic components of input currents caused due to unbalanced input voltages. A laboratory prototype is developed to verify the effectiveness of the control strategy. Experimental waveforms and harmonic spectrums show excellent agreement between theoretical analysis and simulation results.

Geometrical visualisation of indirect space vector modulation for matrix converters operating with abnormal supplies

“…They together are the system inputs, while the output voltage space vector v o = v oα + jv oβ and the input current space vector i i = i iα + ji iβ are the system output variables. The existing modulation methods were derived based on the space vectors or similar quantities that are the products of switch states and systems inputs [14][15][16][24][25][26][27][28][29][30][31][32][33][34]. For example, in [24] the line-line voltage space vector can be defined by…”

“…3a. However, they are distinct from their voltage and current counterparts in the existing ISVM algorithms [14][15][16][24][25][26][27][28][29][30][31][32][33][34] where the output line voltage and the input current space vectors depend on the products of the SSMs and the system inputs, and hence are varying in terms of length, as shown in Fig. 3b.…”

“…The feedforward method can be incorporated into the ISVM technique by modifying the switching functions of either the virtual rectifier or inverter to suppress the input disturbances [28][29][30][31][32][33][34]. This is analogous to the pulse width modulation algorithms for traditional back-to-back converters [24].…”

“…However, the averaged DC-link current is variable, which can complicate the input current synthesis. If the rectifier switching functions are chosen to be sinusoidal which results in a constant DC-link current but a varying DC-link voltage, the inverter switching functions have to be modified accordingly to maintain sinusoidal and balanced output waveforms [30][31][32][33]. It is also possible to regulate both input and output side switching functions synchronously in one step [34].…”

Balanced Current Control Strategy for Current Source Rectifier Stage of Indirect Matrix Converter under Unbalanced Grid Voltage Conditions

“…In order to reduce the distortion, the modulation strategies of the IMC under unbalanced voltage conditions of the three-phase grid connected to the CSR stage are researched [21,22]. This paper proposes a control strategy for balanced input currents of an AC-AC power conversion system using an IMC under unbalanced grid voltage conditions.…”