Resolver Decoder

Compute electrical angular position of resolver

  • Library:
  • Motor Control Blockset / Sensor Decoders

Description

The Resolver Decoder block calculates the electrical angular position of the resolver from the resolver sine and cosine output signals.

The resolver uses a primary sinusoidal excitation input signal to generate the modulated secondary sine and cosine waveforms.

You must normalize these waveforms (within the range of [-1,1] and centered at 0) and sample them to obtain the secondary sine and cosine input signals of the Resolver Decoder block.

The block computes and outputs the resolver position in [0, 2π] radians. The block can also add a phase delay to the sampled sine and cosine signals with respect to the excitation signal.

Note

The block inputs should have identical amplitude and data types (either signed fixed or floating point).

Equations

The block computes the average, peak amplitude values, and the sign of the peak amplitude of a signal cycle as

average=1ni=0n1(|i|)

peak=average×π2

Sign of Peak=Sign of [i=phase delayn21+phase delayi]

where:

  • average is the average amplitude value of a signal cycle

  • n is the number of samples per excitation cycle

  • peak is the peak amplitude value of a signal cycle

The block computes the electrical angular position of the resolver as

θ=atan2usin_peak ucos_peak 

where:

  • usin_peak is the peak of the secondary sine signal

  • ucos_peak is the peak of the secondary cosine signal

  • θ is the electrical angular position of the resolver

Ports

Input

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Secondary sine waveform output from the resolver that is sampled and normalized within the range of [-1, 1] and centered at 0.

Data Types: single | double | fixed point

Secondary cosine waveform output from the resolver that is sampled and normalized within the range of [-1, 1] and centered at 0.

Data Types: single | double | fixed point

Output

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Electrical angular position of the resolver (and the rotor) in [0, 2π] radians.

Data Types: single | double | fixed point

Parameters

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The phase delay that the block must add to the Sin and Cos input port signals.

Number of samples available in one cycle of the Sin and Cos input port signals.

The data type of the resolver position output θ.

Introduced in R2020a