soft4pes.control.common.utils

Utility functions and classes for the control module.

Classes

FirstOrderFilter	General first-order filter.
DiscreteTransferFunction	Generic discrete-time transfer function implementation.

Functions

wrap_theta(theta)	Wrap the angle theta to the range [-pi, pi].
get_modulating_signal(v_ref, v_dc)	Convert a voltage reference to a modulating signal.
magnitude_limiter(input_signal, limit)	Limit the input in to maximum magnitude. The input can be in alpha-beta or dq-frame, and given

Module Contents

soft4pes.control.common.utils.wrap_theta(theta)

Wrap the angle theta to the range [-pi, pi].

Parameters:

theta (float) – The angle in radians.

Returns:

The wrapped angle in radians.

Return type:

float

soft4pes.control.common.utils.get_modulating_signal(v_ref, v_dc)

Convert a voltage reference to a modulating signal.

Parameters:

• v_ref (ndarray) – The reference voltage in alpha-beta frame.

• v_dc (float) – The dc-link voltage.

Returns:

The modulating signal in abc-frame.

Return type:

ndarray

soft4pes.control.common.utils.magnitude_limiter(input_signal, limit)

Limit the input in to maximum magnitude. The input can be in alpha-beta or dq-frame, and given as a vector or complex number.

Parameters:

• limit (float) – Maximum magnitude [p.u.].

• input_signal (1 x 2 ndarray of floats or complex) – Unlimited input [p.u.].

Returns:

Limited output [p.u.].

Return type:

1 x 2 ndarray of floats

class soft4pes.control.common.utils.FirstOrderFilter(w_bw, size)

General first-order filter.

Parameters:

• w_bw (float) – The bandwidth of the filter [p.u.].

• size (int) – The size of the signal to be filtered, i.e. the length of the input vector.

w_bw

The bandwidth of the filter [p.u.].

Type:

float

output

The filtered signal.

Type:

ndarray

update(value_in, Ts, base)

Update the filter with a new input signal of the defined size.

Parameters:

• value_in (ndarray) – The input signal to be filtered.

• Ts (float) – The sampling interval [s].

• base (object) – The base values object containing the base angular frequency.

class soft4pes.control.common.utils.DiscreteTransferFunction(numerator_coeffs, denominator_coeffs=None)

Generic discrete-time transfer function implementation.

The transfer function is defined as

Y(z) / U(z) = (b0 + b1 z^-1 + … + bm z^-m)

(a0 + a1 z^-1 + … + an z^-n)

Parameters:

• numerator_coeffs (array-like) – Numerator coefficients of the transfer function.

• denominator_coeffs (array-like, optional) – Denominator coefficients of the transfer function. If not given, [1] is used.

apply(input_signal)

Apply the discrete transfer function to the input signal.

Parameters:

input_signal (float or array-like) – The current input signal.

Returns:

The filtered output signal.

Return type:

float or ndarray