Reference parameters

The reference parameters are treated as the most fundamental constants. The rest of the system scales the control approaches accordingly. If some derived parameter then ratiometrically depends on a reference parameter, it's value unit will be depicted e.g. as [.iref].

info

• The following variables are located in the /driver folder.
• Not all the params and states may be present. It depends on the current configuration of your application.

VECTOR and BLDC shared

Parameters

iref [A]

The stator reference current. During the normal circumstances, the amplitude of motor phase current stays below the value specified by this parameter.

E.g. When you issue a command 1 and no d-axis control is configured, this current will be fed into the Q-axis of the motor.

warning

Set iref with thermal, sensing, and control stability margins in mind. An excessively high reference does not translate into a smoother drive: the resulting current peaks work against the flat torque-versus-speed curve you usually want, and in the field-weakening region at high speed the control loop can destabilize, with potentially catastrophic consequences. The risk grows when iref is combined with aggressive d-axis settings. Beyond a certain current, the motor can also become uncontrollable because the winding inductance drops with saturation — see current control for that (related) mechanism.

uref [V, .Vbatt]

The Q-axis reference voltage.

• Setting this parameter to zero value (default) allows the driver to use all the available voltage.
• Setting this parameter to a positive value defines the reference voltage for the torque generating axis. The motor speed in voltage mode is then independent of the DC supply voltage and during normal circumstances, Q-axis voltage stays below the value specified by this parameter.
• Setting this parameter to a negative value instructs to use a portion of the actual DC voltage (usualy referred to as maximum "duty cycle" within the competitor's products).

E.g. When you issue a command 1, this voltage will be fed into the Q-axis of the motor.

Changed in driver 6

A reduced uref (positive or negative form) now also shifts the field weakening active range proportionally - the FW onset follows the resolved voltage reference instead of the full bus voltage. Behavior with the default uref = 0 is unchanged. See flux weakening.

irefr [A, .iref]

The regeneration Q-axis current reference. Normally, the iref is used to derive the Q-axis current reference. Nevertheless, if the following conditions are met :

1. Driver mode is not CRT or SCR
2. Motor is decelerating (braking) a different reference might be forced. The value of this parameter sets the regeneration reference as follows: Setting this parameter to zero value (default) disables this functionality. Setting this parameter to a negative value of instructs to use a specified current for regeneration in [A]. Setting this parameter to a positive value of instructs to use a portion of the iref.

ipeak [A]

Peak phase current. If the immediate motor current raises above ipeak at any time in any of the phases, the current is immediately limited to this value by a fast protection independent of the current PID (see Current control). If the condition persists, over-current flag is raised in /driver/stat status word.

Special value: The absolute value is used. Negative value hereby switches the motor direction globally.

rref [RPM]

Reference speed. It is used for PID speed closed loop. More

pref [rad]

Reference angle. It is used for PID position closed loop. More

Only BLDC

aac

Maximum advancing

aacpart

How big part to "cut" from the command for advancing

ipbrake [A]

Current used as reference and peak current for [driver mode = 15] (braking)

startc [.iref]

When motor is starting up in sensorless mode, this parameter acts as the multiplier for the iref stator current reference.

/rest/hallc [.iref]

When motor is driven in sensored (hall) mode (incl. startup), this parameter acts as the multiplier for the iref stator current reference.