Elmo HARSFEN0602, HARmonica software manual 115, Current controller

HARSFEN0602ElmoHARmonicaSoftwareManual PRELIMINARYDRAFT

10 The current controller

This section describes the current controller and its parameterization. In addition, it describes the current limiting process and the amplifier protections.

The commands relevant to the current controller are:

Command	Description
TS	Current controller sampling time
KP[1]	Proportional gain of current controller (nominal voltage)
KI[1]	Integral gain of the current controller (nominal voltage)
XP[4]	Time constant for DC power bus filter
XP[5]	Step limiter for torque command filter
XP[6]	Time constant for torque command filter
MC	Largest available amplifier current
PL[1]	Application peak current limit
PL[2]	Duration for the peak current limit
CL[1]	Continuous application current limit

Please read about the above instruction in the Command Reference Manual to complement the material of this chapter.

This Chapter deals with currents in Amperes. The definition we use for an "Ampere" of three-phased motor current is explained in the section 2.3: "Related Software

The Harmonica energizes all the 3 motor terminals simultaneously. This means it has to control two current components simultaneously. It must control only two current components, not three, since the phase currents are linearly dependent – the sum of all the phase currents is identically zero. The Harmonica has a vector current controller. This means that the two directly controlled current components are:

IQ: The current component that produce magnetic field in the desired direction

•(normally perpendicular to the rotor fixed magnet field)

ID: The current components that produce magnetic field orthogonal to the desired

direction (normally parallel to the rotor fixed magnet field) The structure of the current controller is as follows:

Peak/Continuous limit

saturation

				PW M output
Torque	Q	VQ		Va
Pre-filter	P+I controller
comm and			CoordinateOutput
	- Σ			Vb	Power bridge
			transform	Vc		& motor
0	D	VD	Commutation
	P+I controller
				angle
-
	IQ			Ia
			Input	Ib
			Coordinate
				Ic
Σ	ID		transform
Figure 10: Current controller structure				Currentθ		sensors

The input coordinate transform retrieves the IQ and ID (Active and Reactive) components of the motor currents.

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