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5.6.3 D-Q Axis Current Control
Fig. 5.6.3 shows a block diagram of D-Q axis current control.
This system controls power supply current by separating it into active current and reactive current. This system
controls current on the D-Q coordinates and can handle both reference and feedback values as DC values. This
means that it can control AC as a DC value, achieving high-performance control.
(1) IQ control
The active current reference, which is the result of the voltage control described above, is used as an IQ
reference. This IQ reference and IQ feedback signal are input and proportional/integral operations are
carried out on them to obtain an EQ reference.
(2) ID control
The reactive current of the power supply is used as an ID reference. This ID reference and the ID feedback
signal are input and proportional/integral operations are carried out on them to obtain an ED reference.
(3) Voltage phase detection (PLL)
VD_FBK is obtained from the AD voltage by coordinate conversion. This VD_FBK is input to the
proportional integrator and integration is carried out on the output to obtain the phase of the input voltage
(CNV_Q0). This CNV_Q0 is used in coordinate conversion for calculating VD_FBK and coordinate
conversion for calculating voltage reference.
When CNV_Q0 is identical to the phase of the actual input voltage, VD_FDK becomes “0” logically. That is,
here, the phase of the input voltage is detected by performing proportional/integral control so that VD_FBK
always becomes “0.”
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