Internal Model Current Control of Brushless Doubly Fed Induction Machines

Abstract

Abstract:In the wind energy generation system, the brushless doubly-fed induction machine (BDFIM) has shown significant application potential, since it eliminates the electric brush and slip ring. However, the complicated rotor structure increases the control difficulty, especially resulting in complicated coupled terms in the current sub-system, which deteriorates the dynamic performance and reduces the system robustness. In order to address the problems caused by complex coupled terms, an internal model current control strategy is presented for the BDFIM, and an active damping term is designed for suppressing the disturbance caused by the total resistance. The proposed method simplifies the controller parameters design, and it achieves the fast-dynamic response and the good tracking performance, as well as good robustness. On the other hand, the feedforward term composed by the grid voltage is added to the internal model controller in order to suppress the disturbance when the symmetrical grid voltage sag happens. Finally, the simulation and experimental results verify the feasibility and effectiveness of the proposed method.

Research of the Fundamental Wave of Wound-Rotor Brushless Doubly-Fed Machine

“…Table 2 lays out the original expressions of 23 groups of coils and their phase separation. Compared to the statement (12), the phase separation needs a bit of transformation, as the range of arc cosine functions cover from 0 to . In Figure 8, the x-axis represents the rotor positions, while the y-axis is for the corresponding value of induced EMF.…”

“…According to the basic theory of induction machine windings, when a suit of p-pole pair winding is embedded in a machine which has z slots, a special kind of harmonic called tooth harmonic will be produced simultaneously [11][12][13]. The pole pairs of tooth harmonic magnetic potential can be expressed as:…”

“…Different from other high-level harmonics, the tooth harmonic cannot be enervated by adjusting the winding coefficient. The distribution coefficient and winding pitch coefficient of an n-level tooth harmonic can be calculated as: Statement (2) and (3) [12,13] have demonstrated the special property of tooth harmonics. Conclusions can be derived from the statements above, that the winding coefficient of the tooth harmonic wave and the fundamental wave shares a same value, that is, it is unrealistic to weaken the tooth harmonic wave by enervating its coefficient.…”

Internal mode control based coordinated controller for brushless doubly fed induction generator in wind turbines during fault conditions

“…A vector controller oriented on the PW reference frame is proposed to regulate the speed and reactive power independently [20]. The reactive power and speed are calculated analytically using the mathematical model of BDFIM while the PI controller gains are derived through the IMC method [21]. In the vector control scheme, the dq components of PW and CW currents are regulated to obtain the desired reactive power and speed of the machine.…”

Nonlinearity compensation of low-frequency loudspeaker response using internal model controller

“…So, the main challenge is to make a compensator to reduce the nonlinearity of the loudspeaker. In terms of eliminating the nonlinearity of loudspeakers and reducing distortion, new controllers are needed such as automatic compensation [9], Fractional Order [10][11][12], Internal Model Controller [13][14][15][16]. Internal Model Controller (IMC) is one of the compensators that can be used because it has advantages in terms of speed and accuracy of the controller.…”