BCFQ
Battery current compensation and q-d-axis feed-through mechanism.
- The following variables are located in the
/driver/dacfolder. - This page is related to the VECTOR algorithm only.
Playing with the flux current is tricky. Certain situations may result in a spinning motor, even with the "stop" command issued. This subsystem aims to minimize such hazardous states of motor control that may arise due to e.g. wrongly identified shaft sensor or motor non-linearities. At the zero drive command, this subsystem tries to regulate Q axis current in a feedback loop, such that, the battery current is steered to zero. This means that not back-driven motor can not generate torque and, eventually freewheels and stops. Moreover, in connection with the flux weakening subsystem, this loop guarantees that the motor "generates" just the enough power that is required for its own field weakening.
Also, in current drive modes, it is possible to feed the Q-axis current reference by a portion of the actual D-axis current reference (to compensate the residual torque emerged from non-linearities, such as cross-inductances, etc.).
Parameters
tcc [.iref]
The maximum current for the compensation <0:disabled>
tdg [-]
Battery current compensator DC gain. The higher the value, the faster the Q-axis current reference is regulated in order to achieve zero DC-side current.
tqf [-]
Torque compensator Q-axis feed-through ratio. The higher the value, the more of D-axis current reference is mapped to the Q-axis current reference.
States (only esc5)
bcref [A]
The calculated q-axis battery current compensator reference. Output from the BCFQ block, mapped to Q-axis current reference in non-zero motor current commands.