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PID Speed Control Loop - Switching

Designer

Description

This example shows a more detailed circuit- and logic-level implementation of the PID Control Loop shown in the companion example, “PID Speed Control Loop – Continuous”. The ideal motor drive block of the “Continuous” version is expanded here, to include both a H-bridge motor drive, and also the digital logic necessary for converting the continuous PID controller output into the desired PWM signals that are distributed to drive the gates of the power MOSFET switches. The MOSFET model was calibrated to represent an IRF3710, using only information published on the manufacturer’s datasheet.
The rest of the system, including the PID block-diagram controller, the mechanical fan load and the DC Motor characterized to represent an FRC (First Robotics Competition) CIM Motor, are the same as in the Continuous version. While the simulation time for this switching version is significantly longer, more detailed information about practical circuit performance and component sizing is available. For example, the fan speed step response is somewhat different from the conceptual design, because of the losses in the MOSFETs under high current conditions, as well as voltage drop in the battery. Also, information regarding component stress levels within the “datasheet specified” MOSFETs and Diodes is provided.

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PID Speed Control Loop - Switching

Designer

Description

This example shows a more detailed circuit- and logic-level implementation of the PID Control Loop shown in the companion example, “PID Speed Control Loop – Continuous”. The ideal motor drive block of the “Continuous” version is expanded here, to include both a H-bridge motor drive, and also the digital logic necessary for converting the continuous PID controller output into the desired PWM signals that are distributed to drive the gates of the power MOSFET switches. The MOSFET model was calibrated to represent an IRF3710, using only information published on the manufacturer’s datasheet.The rest of the system, including the PID block-diagram controller, the mechanical fan load and the DC Motor characterized to represent an FRC (First Robotics Competition) CIM Motor, are the same as in the Continuous version. While the simulation time for this switching version is significantly longer, more detailed information about practical circuit performance and component sizing is available. For example, the fan speed step response is somewhat different from the conceptual design, because of the losses in the MOSFETs under high current conditions, as well as voltage drop in the battery. Also, information regarding component stress levels within the “datasheet specified” MOSFETs and Diodes is provided.

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Single-string Test - ACME AS123 LED Driver with Dimmer Control

Designer

Test Silego AN-1056 Voltage Controlled PWM

Designer

Test Silego Voltage Controlled PWM

Designer

PMSM Motor and PWM NMOS Drive

Designer

Description

Permanent Magnet Synchronous Machine (PMSM) and PWM Drive circuit, with mechanical load. The drive includes a D-Q control algorithm, and uses space-vector modulation (SVM) to generate the digital PWM signals to drive the Power MOSFET switches of the inverter.

There are two other versions of this design. The first, "PMSM Motor And Ideal Drive", uses continuous Clarke and Park Transform models and an ideal voltage drive to represent the main features of the field-oriented control system., Another version, "PMSM Motor and PWM Drive", it similar to this version but uses ideal switches.

This version is the most detailed and therefore simulated the most slowly. It is well suited for understanding the performance of the Power MOSFETs in the context of the system, In the waveform plot on the right, the actual motor shaft angle (orange waveform) and the A-phase current (dark blue waveform) are shown. These are very similar to the results for the other two versions of the design. But the waveform plot on the left provides insight into the performance of the C-phase inverter pull-up switch. The MOSFET current Ids (green waveform), and the average power dissipated in the device (red waveform) are shown. This design can be used to size specific parts in the drive electronics, by comparing the operating conditions to which they are exposed, relative to their rated operational limits.

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Fault Testing - ACME AS123 LED Driver with Dimmer Control

Designer

PMSM Motor and Ideal Drive

Designer

PMSM Motor and PWM Drive

Designer

Description

Permanent Magnet Synchronous Machine (PMSM) and PWM Drive circuit, with mechanical load. The drive includes a D-Q control algorithm, and uses space-vector modulation (SVM) to generate the digital PWM signals to the switches of the bridge.

The waveform plot in the upper left shows the drive command (light blue waveform), with values 0 to 1, where 1 is commanding the maximum quadrature current of 10 A. The motor's response is the output shaft angle in radians (orange waveform), and shows that increasing torque command results in greater rotational displacement against the load spring. The waveform plot in the upper right shows the actual motor torque (green waveform) and the A-phase current (dark blue waveform).

In a companion version of this design, "PMSM Motor And Ideal Drive", Clarke and Park Transform models are used with a continuous ideal voltage drive.This shows the ability to develop motor control and drives at the abstract level and at the circuit level.

In yet another version of this design example, the ideal switches will be replaced with actual power MOSFET device models. This can help in bridge component sizing and performance specification.

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PID Speed Control Loop - Switching

Designer

Description

This example shows a more detailed circuit- and logic-level implementation of the PID Control Loop shown in the companion example, “PID Speed Control Loop – Continuous”. The ideal motor drive block of the “Continuous” version is expanded here, to include both a H-bridge motor drive, and also the digital logic necessary for converting the continuous PID controller output into the desired PWM signals that are distributed to drive the gates of the power MOSFET switches. The MOSFET model was calibrated to represent an IRF3710, using only information published on the manufacturer’s datasheet.The rest of the system, including the PID block-diagram controller, the mechanical fan load and the DC Motor characterized to represent an FRC (First Robotics Competition) CIM Motor, are the same as in the Continuous version. While the simulation time for this switching version is significantly longer, more detailed information about practical circuit performance and component sizing is available. For example, the fan speed step response is somewhat different from the conceptual design, because of the losses in the MOSFETs under high current conditions, as well as voltage drop in the battery. Also, information regarding component stress levels within the “datasheet specified” MOSFETs and Diodes is provided.

About text formats

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