Page 245 - Renewable Energy Devices and System with Simulations in MATLAB and ANSYS

232 Renewable Energy Devices and Systems with Simulations in MATLAB and ANSYS ®
®

×10 4 Power losses
14
Pcu
Pfe
Pmec
12

10

Power (W) 8

6

4

2
0 200 400 600 800 1000 1200
(a) Steps
0.986

0.984

0.982

0.98
Efficiency 0.978

0.976

0.974

0.972

0.97
0 200 400 600 800 1000 1200
(b) Steps
FIGURE 9.19 Evolution of (a) losses during optimization and (b) efficiency of optimal design for an 8 MW,
480 rpm PMSG (Pcu, Pfe, and Pmec are copper, iron, and mechanical losses, respectively).

For surface-mounted PMSGs, L = L = L and, in general of maximum torque per losses, i = 0
q
s
d
d
and thus pure i control is adequate (no reluctance torque is available anyway). Pure i control leads
q
q
to an increase in reactive power Q , which is
e
3 3
P e = V i q < 0; Q e = 1 ω LI q > 0; i d = 0 (9.29)
2
q
2 q 2