Calculation of Semiconductor Power Losses of a Three-Phase Quasi-Z-Source Inverter

Abstract

This paper presents two novel algorithms for the calculation of semiconductor losses of a three‑phase quasi-Z-source inverter (qZSI). The conduction and switching losses are calculated based on the output current‑voltage characteristics and switching characteristics, respectively, which are provided by the semiconductor device manufacturer. The considered inverter has been operated in a stand‑alone operation mode, whereby the sinusoidal pulse width modulation (SPWM) with injected 3rd harmonic has been implemented. The proposed algorithms calculate the losses of the insulated gate bipolar transistors (IGBTs) and the free-wheeling diodes in the inverter bridge, as well as the losses of the impedance network diode. The first considered algorithm requires the mean value of the inverter input voltage, the mean value of the impedance network inductor current, the peak value of the phase current, the modulation index, the duty cycle, and the phase angle between the fundamental output phase current and voltage. Its implementation is feasible only for the Z-source-related topologies with the SPWM. The second considered algorithm requires the instantaneous values of the inverter input voltage, the impedance network diode current, the impedance network inductor current, the phase current, and the duty cycle. However, it does not impose any limitations regarding the inverter topology or switching modulation strategy. The semiconductor losses calculated by the proposed algorithms were compared with the experimentally determined losses. Based on the comparison, the correction factor for the IGBT switching energies was determined so the errors of both the algorithms were reduced to less than 12%.

Sequential model predictive control of quasi Z‐source inverter with fixed frequency operation

“…Higher the load current, lesser the switching loss variation in case of conventional method with respect to the proposed method. Equation to calculate the power loss per IGBT is 47 where is the shoot‐through conduction loss and is the non‐shoot‐through conduction loss.…”

Semiconductor Losses Calculation of a Quasi-Z-Source Inverter with Dead-Time

“…The latter include the inductors' losses, which may be determined as in [9,10], and the capacitors' losses which are generally considered negligible. The calculation of the semiconductor losses represents a challenging task and many methods have been proposed with this regard [11][12][13][14][15][16][17]. In [11], the semiconductor losses were calculated based on the measured voltage and current waveforms of the utilized transistors and diodes.…”

“…This required sensors with high frequency bandwidth due to the fast transients in the current and voltage of the semiconductor devices. On the other hand, in [12][13][14][15][16][17], the semiconductor losses were calculated based on the characteristics provided by the semiconductor device manufacturer. In [12], the switching losses were calculated based on the switching energies determined according to the corresponding switching times and the semiconductor device current and voltage.…”

Efficiency Boost of a Quasi-Z-Source Inverter: A Novel Shoot-Through Injection Method with Dead-Time

“…For D0 ≤ 0.26, the duration of the additional ZSS is long enough to ensure both the mentioned switching transitions of the transistor to be finished completely. Hence, in this region, the switching losses of the transistors are dominant and increase with D0 [33] due to the increase of Vpn as per (2). However, when the applied D0 is higher than 0.26, the turn-on transition into the STS occurs before the previous turn-off transition from the active state into the ZSS has completely finished.…”

“…The variation of the load power did not have a clear impact on the inverter losses difference. This may be explained by the fact that the increase of the load power primarily leads to the increase of the transistor conduction losses, whereas the increase of the switching losses remains less pronounced [33]. Note also that the load power of 3000 W was not achieved for f sw = 10 kHz for both the considered methods because this would cause the case temperature of the IGBT-diode pair to surpass the maximum allowed temperature, set to 130 • C. This may ultimately destroy the device.…”