Current control response

Could anyone please explain me what is the meaning of current control response 300 rad/sec and speed control response 10 rad/sec. Why one is 300
and another 10 ?
It will be great help if anyone explain.

These would appear to be from a drive specification. I believe they are values of cutoff frequency for each of the control loops. The cutoff frequency is generally defined as the frequency at which the output is attenuated -3dB relative to the input. So this specification is trying to say that the current control loop is capable of controlling to command values with a frequency up to 300 radians/sec, or about 47.75 Hz. Similarly the speed control loop can correctly control to a command value frequency of 10 rad/sec, or about 1.59 Hz. Keep in mind this is not the same as the frequency the drive will be able to control a motor to. This is purely a measure of the controllers capability, not the system capability.

The required frequency response of the controller is a property of the response of the item being controlled. For example, motor current can respond very quickly to changes to the control effort. This means the controller also needs to respond relatively quickly in order to correct for current errors. Similarly, motor speed would not be expected to change as quickly based on changes to the control effort so the speed controller cutoff frequency doesn't need to be as high.

These values tend to be a measure of raw control capability. They can't necessarily be equated to a more accurate control system. ALL OTHER THINGS BEING EQUAL the device with the higher frequency response will be capable of more accurate control at higher disturbance frequencies. But all other things are seldom equal.

Keith