Motor Electrical Controlled

SWITCH TO API

Description

The Motor Electrical Controlled component is a DC motor model where the user specifies a fixed speed and input voltage, and the motor reports the resulting torque output. This is useful for analyzing motor performance at a given operating point. The component also supports optional signal-based speed control, where an external electrical signal can modulate the motor speed as a fraction of a defined maximum.

This component inherits from Motor Base, which provides the common electrical modeling including armature resistance, armature inductance (via companion model), and back-EMF calculations.

---

Example Use Cases

• Operating Point Analysis: Determine the torque output of a motor at a specific speed and voltage.
• Signal-Controlled Actuation: Use an electrical control signal to vary motor speed proportionally, such as in valve positioning or throttle control systems.
• Power Budget Estimation: Analyze current draw and power consumption at defined operating conditions.

---

Module Implementation

Speed Input Modes

The motor supports two modes for determining speed:

1. Direct Speed Input: When no control signal is connected, the motor uses the user-defined SpeedInput value. If MaxSpeed is set to a non-negative value, the speed is clamped to $\pm {\omega }_{\max }$. Setting MaxSpeed to $-1$ disables the speed limit.

2. Signal-Based Control: When an electrical signal is connected via In_ControlElectricalSignalMsg, the motor speed is determined by normalizing the signal value to a duty ratio and scaling by MaxSpeed:

$$\omega =r\cdot {\omega }_{\max }$$

where $r$ is the normalized signal ratio (0 to 1) and ${\omega }_{\max }$ is the maximum speed.

Signal Normalization

The signal ratio is computed based on the control signal’s value and its defined bounds:

$$r=\frac{V_{\mathrm{signal}}-V_{\min }}{V_{\max }-V_{\min }}$$

where $V_{\mathrm{signal}}$ is the current signal value (voltage or current depending on the signal’s control type), and $V_{\min }$ and $V_{\max }$ are the signal bounds. The ratio is clamped to the range [0, 1].

Back-EMF Calculation

The back-EMF voltage is computed based on the effective motor speed:

$$V_{\mathrm{EMF}}=K_e\cdot \omega$$

where $K_e$ is the back-EMF constant (V/(rad/s)).

Electromagnetic Torque

The electromagnetic torque produced by the motor is:

$${\tau }_e=K_t\cdot I_a$$

where $K_t$ is the torque constant (Nm/A) and $I_a$ is the armature current.

---

Assumptions/Limitations

• The mechanical dynamics are not solved internally; the motor operates at the specified or signal-derived speed.
• When using signal-based control, the signal bounds must be properly configured for correct normalization.
• The electrical time constant of the armature inductance is modeled using a companion circuit approach.