An Active Modulation Scheme to Boost Voltage Utilization of the Dual Converter With a Floating Bridge

Abstract

This paper proposes a capacitor voltage regulation method for the dual converter with a floating bridge for aerospace applications. This topology has previously been reported, but with a constrained voltage utilisation factor due to the need for capacitor voltage regulations. In this paper, the effect of switching states on the voltage variation of capacitor is quantitatively modelled and an enhanced space vector modulation scheme with current feedback is proposed to achieve an active control of the floating capacitor voltages. This proposed method also allows further exploitation and utilisation of converter voltage. The relationship between the allowed modulation index of dual converter and load power factor is obtained and expressed using a fitted polynomial equation. The advantages of the proposed method include boosted voltage utilisation and superior performance in term of capacitor voltage balance. These advantages have been proven through simulation and experimental results on RL loads as well as with an open-end winding induction motor. The proposed modulation scheme can boost the converter voltage utilisation by at least 10% while achieving full four-level operation. More importantly, the higher available voltage allows extending the constant torque region of the motor, the further beginning of field weakening operation could be postponed.

Fixed switching frequency predictive control of an asymmetric source dual inverter system with a floating bridge for multilevel operation

“…It can also be seen from Table 1 that the capacitor control inside the modulation scheme or in cost function algorithm does not have a significant effect on output waveforms for the proposed MMPC controller. All the waveform results shown in this paper were achieved using three‐step commutation to avoid dead‐time spike inherent with a dual inverter with asymmetric sources [19, 20].…”

“…Thus, the controller will give equal importance to the different control variables. The design of the weighting factor is described in (20).…”

“…where g is the total cost function and λ is the weighted factor to normalise the floating voltage error in contrast with the current errors. Using (1)- (20), a model predictive floating capacitor voltage and current control for three-phase open-ended R-L load using a dual inverter with a floating bridge can be implemented, as shown in Fig. 3a.…”

Reliability Oriented Design of Low Voltage Electrical Machines Based On Accelerated Thermal Aging Tests

“…In transport applications, these are essential features, because a compact and lightweight design is desirable. However, the safety-critical nature of mobile applications also imposes strict reliability figures [3,4].…”

Evaluation of strand‐to‐strand capacitance and dissipation factor in thermally aged enamelled coils for low‐voltage electrical machines

“…In terms of thermal stress, a variable temperature profile is preferred to a constant temperature, because the former is representative of the actual condition experienced by high-performance EMs, when they are thermally overloaded for short-time periods (e.g. EMs for aerospace and automotive applications [28,29]). Particular attention is focused on humidity throughout the experimental campaign.…”