Consolidated SVPWM for Single-Phase Fault-Tolerant Control of CFNI-Based Inverter

[i] CFI, capacitor-based four-leg inverter; CFNI, capacitor-based four-leg neutral-point-connected inverter; PPRF, post-fault power ratio factor; SFI, switched-based four-leg inverter; SFNI, switched-based four-leg neutral-point-connected inverter; SOCF, semiconductor overrating cost factor.

Table 2.

Available voltage vectors with neutral point connected to the midpoint of the DC-link capacitor and phase a eliminated.

S_b	S_c	u_α	u_β	V_x	Amplitude
0	0	V_dc/3	0	V₁	V_dc/3
0	1	0	$- V_{dc} / \sqrt{3}$	V₄	$V_{dc} / \sqrt{3}$
1	0	0	$V_{dc} / \sqrt{3}$	V₂	$V_{dc} / \sqrt{3}$
1	1	−V_dc/3	0	V₃	V_dc/3

Table 3.

Available voltage vectors with neutral point connected to the midpoint of the DC-link capacitor and phase b eliminated.

S_c	S_a	u_α	u_β	V_x	Amplitude
0	0	−V_dc/6	$\sqrt{3} V_{dc} / 6$	V₁	V_dc/3
0	1	V_dc/2	$\sqrt{3} V_{dc} / 6$	V₄	$V_{dc} / \sqrt{3}$
1	0	−V_dc/2	$- \sqrt{3} V_{dc} / 6$	V₂	$V_{dc} / \sqrt{3}$
1	1	V_dc/6	$- \sqrt{3} V_{dc} / 6$	V₃	V_dc/3

Table 4.

Available voltage vectors with neutral point connected to the midpoint of the DC-link capacitor and phase c eliminated.

S_a	S_b	u_α	u_β	V_x	Amplitude
0	0	−V_dc/6	$- \sqrt{3} V_{dc} / 6$	V₁	V_dc/3
0	1	−V_dc/2	$\sqrt{3} V_{dc} / 6$	V₄	$V_{dc} / \sqrt{3}$
1	0	V_dc/2	$- \sqrt{3} V_{dc} / 6$	V₂	$V_{dc} / \sqrt{3}$
1	1	V_dc/6	$\sqrt{3} V_{dc} / 6$	V₃	V_dc/3

Voltage vectors in the αβ plane. (a) Fault in a, (b) fault in b, and (c) fault in c.

Table 5.

Adjusted time calculations.

Sector I	Sector II	Sector III	Sector VI
$T_{1} = 3 \frac{V_{s}}{V_{dc}} T_{s} \cos θ$	$T_{1} = \sqrt{3} \frac{V_{s}}{V_{dc}} T_{s} \cos θ$	$T_{1} = 3 \frac{V_{s}}{V_{dc}} T_{s} \cos θ$	$T_{1} = \sqrt{3} \frac{V_{s}}{V_{dc}} T_{s} \cos θ$
$T_{2} = \sqrt{3} \frac{V_{s}}{V_{dc}} T_{s} \sin θ$	$T_{2} = 3 \frac{V_{s}}{V_{dc}} T_{s} \sin θ$	$T_{2} = \sqrt{3} \frac{V_{s}}{V_{dc}} T_{s} \sin θ$	$T_{2} = 3 \frac{V_{s}}{V_{dc}} T_{s} \sin θ$

Optimal switching patterns for the four sectors. PWM, pulse width modulation.

Table 6.

Summarised switching states for the three faulty cases.

	Fault in a		Fault in b		Fault in c
	S_x	S_y	S _x	S_y	S _x	S_y
	S_b	S_c	S_c	S_a	S_a	S_b
V₁	0	0	0	0	0	0
V₂	1	1	1	0	0	0
V₃	1	1	1	1	1	1
V₄	0	0	0	1	1	1

Proposed consolidated SVPWM control block diagram. SVPWM, space vector pulse width modulation.

Proposed single-phase FTC block diagram. CFNI, capacitor-based four-leg neutral-point-connected inverter; FTC, fault-tolerant control; PMSM, permanent magnet synchronous motor; SVPWM, space vector pulse width modulation; PI, proportional-integral.

Table 7.

System parameters.

Parameters	Values
DC-voltage	220V
Cbus	4.4 mF
PWM frequency	16 kHz
Rated power	1,100 W
Rated speed	3,000 rpm
Resistance and inductance	2.875 Ω and 8.5 mH
Pole pairs	4
Viscous friction	0.001 Nms
Rotational inertia J	0.0008 kg·m²
Permanent magnet flux	0.175 Wb

Speed response before and after a fault occurs in phase a at 1 s.

Torque response before and after a fault occurs in phase a at 1 s.

Current response before and after a fault occurs at 1 s, (a) in phase a, (b) in phase b, and (c) in phase c.

Table 8.

Current amplitudes and phase displacements in the three faulty scenarios.

	Amp.	Deph.	Amp.	Deph.	Amp.	Deph.	Amp.	Deph.
i_a	i_N	0	0	-	$\sqrt{3} i_{N}$	$\frac{- π}{6}$	$\sqrt{3} i_{N}$	$\frac{π}{6}$
i_b	i_N	$2 \frac{π}{3}$	$\sqrt{3} i_{N}$	$\frac{π}{6}$	0	-	$\sqrt{3} i_{N}$	$\frac{- π}{6}$
i_c	i_N	$- 2 \frac{π}{3}$	$\sqrt{3} i_{N}$	$\frac{- π}{6}$	$\sqrt{3} i_{N}$	$\frac{π}{6}$	0	-
i_n	0	-	3i_N	0	3i_N	0	3i_N	0

Current THD in faulty case. THD, total harmonic distortion.

References

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Articles in this issue

DOI: https://doi.org/10.2478/pead-2026-0029 | Journal eISSN: 2543-4292 | Journal ISSN: 2451-0262

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Language: English

Page range: 459 - 475

Submitted on: Jun 4, 2026

Accepted on: Sep 9, 2026

Published on: Oct 14, 2026

Published by: Wroclaw University of Science and Technology

In partnership with: Paradigm Publishing Services

Keywords:

fault-tolerant control,

space vector pulse width modulation,

capacitor-based four-leg neutral-point-connected inverter,

permanent magnet synchronous motor,

field-oriented-control

Related subjects:

Computer sciences,

Artificial intelligence,

Engineering,

Electrical engineering,

Electronics

© 2026 Meriam Miraoui, Mohammed Larbi Elfahyani, Asmae Miraoui, Hana Zekraoui, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 11 (2026): Issue 1 (January 2026)

Consolidated SVPWM for Single-Phase Fault-Tolerant Control of CFNI-Based Inverter

Figures & Tables

Figure 1.

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Figure 2.

Figure 3.

Figure 4.

Table 5.

Figure 5.

Table 6.

Figure 6.

Figure 7.

Table 7.

Figure 8.

Figure 9.

Figure 10.

Table 8.

Figure 11.

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