Sprc080 pdf

The time difference between the two theta readings is the sample time. The Speed Measurement block inherits the sample time from the upstream block in your model. You set the sample time in the upstream block and then the Speed Measurement block uses that sample time to calculate the rotation rate of the motor. Motor speed measurements depend on the sample time you set in the model. Your sample time must be short enough to measure the full speed of the motor.

Two parameters drive your sample time—motor base speed and encoder counts per revolution. To be able to measure the maximum rotation rate, you must take at least one sample for each revolution. For a motor with base speed equal to rpm, which is This sample rate of Using the same sample rate assumption, the minimum speed the block can measure depends on the encoder counts per revolution.

At the minimum measurable motor speed, the encoder generates one count per sample period— For an encoder that generates counts per revolution, this results in being able to measure a speed of [ The differentiator constant is a scalar value applied to the block output. For example, setting it to 1 does not alter the output. This setting can be useful when your motor has multiple pole pairs, and one electrical revolution is not equal to one mechanical revolution.

The constant lets you account for the difference between electrical and mechanical rotation rates. This block includes filtering capability if your position signal is noisy.

Setting the filter constant to 0 disables the filter. The following diagram shows a PID controller with antiwindup. The differential equation describing the PID controller before saturation that is implemented in this block is. Using backward approximation, the preceding differential equations can be transformed into the following discrete equations. The implementation of this block does not call the corresponding Texas Instruments library function during code generation.

See Using the IQmath Library for more information. The inputs to this block are the direct axis Alpha and the quadrature axis Beta components of the transformed signal and the phase angle Angle between the stationary and rotating frames. The outputs are the direct axis Ds and quadrature axis Qs components of the transformed signal in the rotating frame.

The implementation of this block does not call the corresponding Texas Instruments library function during code generation. See Using the IQmath Library for more information. Choose a web site to get translated content where available and see local events and offers. This block implements a bit digital PID controller with antiwindup correction.

The inputs are a reference input ref and a feedback input fdb and the output out is the saturated PID output. The following diagram shows a PID controller with antiwindup. The differential equation describing the PID controller before saturation that is implemented in this block is. Using backward approximation, the preceding differential equations can be transformed into the following discrete equations.