A Comparative Study of Sinusoidal PWM and Space Vector PWM of an Induction Machine
The inverter is a static converter that provides an AC voltage of adjustable amplitude and frequency from a DC voltage source. Any type of inverter (voltage or current) requires a control technique that depends on the type of machine to be controlled. Mai
- PDF / 2,146,875 Bytes
- 7 Pages / 439.37 x 666.142 pts Page_size
- 31 Downloads / 213 Views
SVPWM SPWM Induction machine
1 Introduction The pulse width modulation (PWM) technique is used to control the amplitude and frequency output of the inverter from the inverter switch control signals while limiting the effect of the harmonies [1]. PWM is an extended technique for many applications such as variable speed drives, analog digital conversions, decoupling power supplies [3], etc. The PWM control strategy distinguishes two commonly used approaches the sinus-triangle PWM and the spatial vector PWM. SPWM relies on a comparison of two signals one triangular defines as a carrier that has a very high frequency and the other is sinusoidal defines as a modulating signal. The difference of the two signals generates a pulse train that directly controls the inverter switches. On the other hand, the SVPWM spatial vector control consists in melting a reference voltage vector from the voltage vectors where the frequency and the amplitude are variable [1].
© Springer Nature Switzerland AG 2019 Y. Farhaoui and L. Moussaid (Eds.): ICBDSDE 2018, SBD 53, pp. 307–313, 2019. https://doi.org/10.1007/978-3-030-12048-1_31
308
W. El Merrassi et al.
2 Inverter Topology The inverter is a converter essentially used to have a voltage or alternating current. The figure below shows a three-phase voltage inverter [3] (Fig. 1).
Fig. 1. Three phase voltage source inverter using IGBT interrupters
Mathematical modeling of the three-phase inverter: The voltages at the output of the inverter ðUan ; Ubn ; Ucn Þ are given by the following relationships: 8 < Uan ¼ 23 U01 13 U02 13 U03 Ubn ¼ 13 U01 þ 23 U02 13 U03 : Ucn ¼ 13 U01 13 U02 þ 23 U03
ð1Þ
The state of the switches, supposed to be perfect, can be defined by control Boolean quantities Ci with (i = 1, 2, 3). • Ci ¼ 1 the case where the high IGBT switch is closed and the one from below open. • Ci ¼ 0 the case where the top switch is open and the bottom one is closed. Under these conditions, the voltages Uoi can be written as a function of the control signals Ci Uoi ¼ Udc
1 Ci 2
ð2Þ
By injecting the formula (2) into the equation system (1), we obtain a relation of the simple voltages as a function of the control variables. 8 < Uan ¼ Udc 23 C1 13 C2 13 C3 Ubn ¼ Udc 13 C1 þ 23 C2 13 C3 : Ucn ¼ Udc 13 C1 13 C2 þ 23 C3
ð3Þ
A Comparative Study
309
3 The Control Strategies of the Inverter Sinusoïdal Pulse Width Modulation Sinusoidal PWM methods for Classic inverters or multilevel inverters are enhanced in a wide variety of publications in the technical literature [1, 2, 4–6]. The principal of Sinusoidal PWM is to compare three sinusoidal signals with a phase shift of 2p 3 to a carrier one to generate the driving signals. The Fig. 2 represents the reference signals resulting from the command Varef , Vbref , Vcref and the signal of the carrier vp, each intersection generates the control signals that will be applied to static switches.
Fig. 2. SPWM illustration. (a) Sine-Triangular comparison; (b) Switching pulse after comparison; (Ma = 0.8,
Data Loading...
