外文翻譯----基于tms320f2812dsp的有死區(qū)時(shí)間補(bǔ)償?shù)膕vpwm調(diào)速永磁同步電動(dòng)機(jī)-文庫吧
2024-10-27 19:42 本頁面
【正文】 ia, ib and ic are positive when they flow from the inverter to PMSM, and negative when they flow from PMSM to the inverter. There are eight switch bination states for the six IGBTs in the threephase voltage source inverter, and during the duration of deadtime, there are correspondingly six current bination states for threephase currents ia, ib and ic according to their polarity: (1) ia0, ib0 and ic0。 (2) ia0, ib0 and ic0。 (3) ia0, ib0 and ic0。 (4) ia0, ib0 and ic0。 (5) ia0, ib0 and ic0。 (6) ia0, ib0 and ic0. It is very important and difficult to detect the zerocross point or the polarity of each phase , if the zerocross point is detect directly through A/D converter of DSP or MCU, bigger measurement deviation will be led especially under the condition of small current, which will result in bigger deadtime pensation deviation and also affect the result of deadtime pensation. Therefore, this paper adopts an indirectly method to detect the zerocross point of phase current, which is based on the current vector angle φ in the twophase static reference frame. For convenient analysis and illustration, place the threephase currents ia, ib, ic in the threephase static reference frame and the two current ponents iα , iβ of the current vector in the twophase static reference frame into the same figure, which is shown in . According to the polarity of threephase currents ia, ib, ic, the iα iβ plane in the twophase static reference frame can be divided into six sectors: I(1), II(2), III(3), IV(4), V(5) and VI(6). For each sector in the iαiβ plane, there is a corresponding deadtime pensation rule. In other words, once the sector which the current vector belongs to is known, the deadtime effect can be pensated according to the corresponding pensation , recognizing the sector number of the current vector is the key problem. In this paper, the sector number is determined by thecurrent vector angle φ which can be calculated through the α and β axis ponents of the stator current vector. Equation (1) shows the calculation method of the current vector φ, and equation (2) shows the relationship between the sector number and the current vector φ. φ=kπ +arctan（ iβ /iα） (k = 0,1) . Current Polarity and Current Vector Angle ? TABLE I DEADTIME COMPENSATION RULES TABLE OF SVPWM ??????????? π /6 ) φ( π π 6 3 π π /2φ(7 π 7 π 5 7 π π /6φ(5 π 5 π 45 π π /6φ( ππ/ 3π /2 )φ( ππ/ 2π /6 )φ( π π 1=s e c t o r (2) For threephase voltage source inverter, the essence of deadtime pensation is to pensating the voltage deviation. However, in the digital motor driving and control system, voltage regulation is implemented through pulse width modulation, that is, through regulating the duty cycle of voltage pulse which has something to do with the pulse width T in one PWM period Tpwm. Therefore, in fact it is the pulse width T that is pensated in the practical application. TABLE I shows the deadtime pensation rules corresponding with the polarity of threephase currents ia,ib,ic and the sector number of the current vector in the iαiβ plane. It can be seen that for different sectors of the iαiβ plane, the pensation values are correspondingly different. In one word, the proposed deadtime pensation method can be carried out through the following steps: (1) Calculate the current vector angle φ through the α and β axis ponents of the stator current vector in the twophase static reference frame according to equation (1). (2) Determine the sector number through the current vector angle φ according to equation (2). (3) Execute
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