Aalto-Electric-Drives/motulator: Release 0.20.1

New

• A diode bridge can feed a DC load through a DC choke instead of a DC bus. The load gives its DC port DCPort(e, R, L), the dual of ACPort, and the bridge solves its DC voltage together with the leg voltages and outputs the DC current i_dc (#347)
• The devices of a diode bridge can be gated through the mask DiodeBridge.gated, which models thyristors: a floating leg is clamped to a rail only through a gated device, and the device turns off when its current reverses (#347)
• GridConverterSystem takes an optional dc_load connected to the DC bus, e.g., a battery model (#347)
• Converter.sample() gives the signals that the model evaluates at the solution points while the converter is blocked, the voltage by default (#347)
• DCPort, dc_voltage, diode_margin, leg_voltages, and update_diodes are exported from motulator.common.model, and Measurements, Feedbacks, and References from motulator.grid.control, for converters and control systems in related packages (#347)

Interface changes

• A controlled converter without gate blocking no longer needs an enabled input, since the simulation reads the blocked property of the converter (#346)
• The defaults ControlSystem.compute_standby_output() and ControlledConverter.set_enable() raise TypeError when gate blocking is not supported, so a control system without gate blocking needs no override (#346)
• The parameter of Converter.extend_history() is positional-only, so the existing overrides stay compatible (#347)

Other changes

• The simulation tracks the gate enable of each control system instead of comparing it with converter.blocked, since a gated bridge stays blocked while enabled. The results of the existing models are unchanged (#347)