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Brushless DC (BLDC) motors and Permanent Magnet Synchronous Motors (PMSMs) have become common in refrigerator compressors to meet stringent energy-efficiency certifications. You can create an energy-efficient compressor by implementing a BLDC or PMSM driver and a three-phase inverter with variable speed operation. Variable speed control is a no-cost option that can be implemented in software to enable the compressor cooling system to efficiently maintain a steady temperature. Inverter-based variable-speed control is resilient to grid voltage fluctuations and requires fewer start and stop operations, which prolongs the compressor life. Field-Oriented Control (FOC) can be used to reduce acoustic noise from the compressor and significantly improve its energy efficiency. This type of implementation replaces an on/off control, which consumes more energy and shortens the motor’s life with every start and stop.

We offer a broad lineup of devices for refrigerator compressor designs that include dsPIC® Digital Signal Controllers (DSCs), MOSFET and Insulated-Gate Bipolar Transistor (IGBT) gate drivers, and integrated analog ICs for interfacing sensors. Our high-performance dsPIC DSCs have advanced motor control PWMs and integrated high-speed Analog-to-Digital Converters (ADCs), op amps and high-speed analog comparators to simplify implementation of advanced motor control and Power Factor Correction (PFC) to reduce your overall system BOM cost.

Many Functional Safety hardware peripherals and functions are available on the dsPIC33 device family to increase the reliability and redundancy for refrigerator applications. These features include Flash memory error correction, RAM integrity checks, CPU trap instructions and system-level monitors like Power-on Reset (POR), Brown-out Reset (BOR), Windowed WatchdogTime (WWDT), Deadman Timer and system clock with internal back-up oscillators. We also provide Class-B Safety Software libraries for dsPIC33 DSCs to reduce your development time and simplify safety compliance.

You can shorten your development cycle by using our comprehensive development tools and tested reference designs for rapid prototyping of high-voltage motor control applications. Our motorBench® Development Suite, a Graphical User Interface (GUI)-based software tool, allows you to measure motor control parameters and generate royalty-free motor control source code to speed up your development time

dsPIC® Refrigerator Compressor Reference Design

Refrigerator Compressor Application Diagram

Refrigerator Compressor Reference Design

This refrigerator compressor reference design will help you rapidly prototype and develop a cost-effective design using a dsPIC DSC.


  • Speeds development time with a turnkey example design that includes rich protection features, motor control and application source code, user guide and multiple communication ports
  • Provides smoother torque and better start and stop characteristics using FOC, which enables quieter compressor operation and a longer lifespan
  • Reduces system-level BOM cost with its high-performance dsPIC33 core and control peripherals for enabling sensorless FOC, DC-DC control for auxiliary power supply and single-shunt current sensing with on-chip op amps

Other Reference Designs

Air Conditioner Reference Design

Our Air Conditioner Reference Design, based on the dual-core dsPIC33CH family of Digital Signal Controllers (DSCs), demonstrates efficient control of the condenser fan, compressor, PFC and the overall application logic implementation. The high-performance dsPIC33C DSCs offer the right set of peripherals for dual-motor control and reduce the need for three controllers down to one for cost and space savings in your design.

Low-Power High-Voltage Motor Control Reference Design

This high-voltage reference design board is targeted to control AC Induction Motors (ACIMs), Permanent Magnet Synchronous Motors (PMSMs) and Brushless DC (BLDC) motors in sensored or sensorless operations. The board is designed to demonstrate the capabilities and efficiency of high-voltage motor control operations at a low power of up to 150W.

Digital Power Interleaved PFC Reference Design

This reference design provides an easy way to evaluate the power and features of dsPIC Digital Signal Controllers for an Interleaved Power Factor Correction (PFC) application. The Interleaved PFC reference design unit works with a universal input voltage range and produces a single high-voltage DC output up to 350W of power.

Hardware Development Tools

dsPICDEM™ MCHV-3 Development Board (High Voltage)

The dsPICDEM MCHV-3 Development Board enables you to evaluate and develop a wide variety of motor control applications using a dsPIC Digital Signal Controller (DSC). This development system is targeted to control Brushless DC (BLDC) motors, Permanent Magnet Synchronous Motors (PMSMs), and AC Induction Motors (ACIMs) in sensor or sensorless operations. The rated continuous output current from the inverter is 6.5A (RMS). This allows up to approximately 2 kVA output when running from a 208V to 230V single-phase input voltage. The system is ideally suited for running a standard three-phase induction motor of up to 1.4 kW (1.8 HP) rating or a slightly higher rated industrial servo-motor.

400W 220 VAC Servo Motor

The Leadshine (EL5-M0400-1-24) 400W 220 VAC Brushless AC Servo Motor is designed for high-torque industrial applications. A 2,500-line incremental encoder is attached for servo positioning. The rated speed is 3,000 RPM and the peak speed is 4,000 RPM. The rated torque is 1.27 Nm and the peak torque is 3.82Nm. It responds quickly and moves quietly and smoothly with high precision for control.

Software Development Tools

Motor Control Library

The Motor Control Library contains function blocks that are optimized for the dsPIC33 families of Digital Signal Controllers (DSCs). All functions in this Motor Control library have input(s) and output(s), but do not access any of the DSC peripherals, making the library modular to use across the dsPIC33 families.

motorBench® Development Suite

The motorBench Development Suite is a Graphical User Interface (GUI)-based software development tool for Field Oriented Control (FOC), performing accurate measurement of critical motor parameters, automatic tuning of feedback control gains and generating source code for an MPLAB® X IDE project utilizing the Motor Control Application Framework (MCAF). This graphical, interactive development environment helps you save time in starting up and running new motors with no load or a constant load, especially when the motor parameters are unknown. The motorBench Development Suite is an MPLAB X IDE plug-in.

Motor Control Simplified

Microchip offers a rapid prototyping solution that allows compiling and flashing a Simulink model of a motor control system into a dsPIC® DSC with a single push of a button. The Simulink blocksets and models are supported by Microchip’s devices and development boards for a complete hardware and software motor control solution to make prototyping your next motor control design easier.

Application Notes

Title Download
AN2590 - Sensorless FOC for PMSM Using Reduced Order Luenberger Observer - Download
AN1292 - Sensorless Field Oriented Control (FOC) for a Permanent Magnet Synchronous Motor (PMSM) Using a PLL Estimator and Field Weakening (FW) Download
AN1278 - Digital Power IPFC Reference Design Application Note Download
AN1106 - Power Factor Correction in Power Conversion Applications Using the dsPIC® DSC Download
AN857 - Brushless DC Motor Control Made Easy Download


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