Sensorless Trapezoidal Commutation for High‑Speed BLDC Motor Applications: MCLV‑48V‑300W and dsPIC33AK512MC510 Motor Control DIM - Modified AN1160

1. INTRODUCTION

Readme describes the setup requirements for high-speed Brushless DC (BLDC) Motor applications using sensorless trapezoidal commutation on the hardware platform EV18H47A "MCLV-48V-300W Development Board" and EV67N21A "dsPIC33AK512MC510 Motor Control Dual In-line Module (DIM)".

For details about sensorless trapezoidal commutation, refer to Microchip application note AN1160 “Sensorless BLDC Control with Back-EMF Filtering Using a Majority Function”

Enhance your embedded applications with Microchip's high-performance dsPIC® Digital Signal Controllers (DSCs). Visit our Motor Control and Drive page to stay updated on the latest motor control solutions from Microchip.

Note:
The dsPIC33AK512MC510 is a Digital Signal Controller (DSC) from Microchip Technology and part of the dsPIC33AK512MPS512 family, designed for motor control and other high-performance embedded system applications.
The firmware does not use majority function for back EMF filtering as in AN1160 “Sensorless BLDC Control with Back-EMF Filtering Using a Majority Function”

2. SUGGESTED DEMONSTRATION REQUIREMENTS

2.1 Motor Control Application Firmware Required for the Demonstration

To clone or download this application firmware on GitHub,

• Navigate to the main page of this repository and
• On the tab <> Code, above the list of files in the right-hand corner, click Code, then from the menu, click Download ZIP or copy the repository URL to clone.

Note:
In this document, hereinafter this firmware package is referred as firmware.

2.2 Software Tools Used for Testing the firmware

• MPLAB® X IDE v6.30
• Device Family Pack (DFP): dsPIC33AK-MC_DFP v1.4.172
• Curiosity/Starter Kits Tool Pack : PKOB4_TP v1.23.1741
• MPLAB® XC-DSC Compiler v3.31
• MPLAB® X IDE Plugin: X2C-Scope v1.7.0

Note:
The software used for testing the firmware prior to release is listed above. It is recommended to use these or later versions of the tool for building the firmware. All previous versions of Device Family Packs (DFP) and Tool Packs can be downloaded from Microchip Packs Repository.

2.3 Hardware Tools Required for the Demonstration

• MCLV-48V-300W Development Board (EV18H47A)
• dsPIC33AK512MC510 Motor Control Dual In-line Module (EV67N21A)
• 24V Power Supply (AC002013)
• 3115-900Kv Brushless DC Motor - ePropelled APM3115-Kv900 (ePropelled)

Note:
All items listed above except ePropelled APM3115-Kv900 Brushless DC Motor are available at microchip DIRECT. The ePropelled APM3115-Kv900 Brushless DC Motor is referred as Sparrow APM3115-Kv900.

3. HARDWARE SETUP

This section describes the hardware setup required for the demonstration.

Note:
In this document, hereinafter the MCLV-48V-300W Development Board is referred as development board. Refer the MCLV-48V-300W Inverter Board User's Guide for more information about the development board.

1. Motor currents are amplified on the MCLV-48V-300W development board; it can also be amplified by the amplifiers internal to the dsPIC33AK512MC510 on the DIM. The firmware and DIM are configured to sample and convert internal amplifier outputs ('internal op-amp configuration') by default to measure the motor currents. Table-1 summarizes the resistors to be populated and removed to convert the DIM from ‘internal op-amp configuration’ to ‘external op-amp configuration’ or vice versa.

   

2. Insert the dsPIC33AK512MC510 Motor Control DIM into the DIM Interface connector J8 on the development board. Make sure the DIM is placed correctly and oriented before going ahead.

   

3. Connect the 3-phase wires from the motor to PHC, PHB, and PHA of the connector J4(no specific order), provided on the development board.

   

4. Plug the 24V power supply to connector J1 on the development board. Alternatively, the development board can also be powered through connector J3.

   

5. The board has an onboard programmer PICkit™ On Board (PKOBv4) , which can be used for programming or debugging the microcontroller or dsPIC DSC on the DIM. To use the onboard programmer, connect a micro-USB cable between the Host PC and connector J16 on the development board.

   

   Alternatively, connect the Microchip programmer/debugger MPLAB® PICkit™ 5 In-Circuit Debugger(PG164150) between the Host PC used for programming the device and the ICSP header J9 on the development board (as shown). Ensure that PICkit 5 is oriented correctly before proceeding.

   

4. SOFTWARE SETUP AND RUN

4.1 Setup: MPLAB X IDE and MPLAB XC-DSC Compiler

Install MPLAB X IDE and MPLAB XC-DSC Compiler versions that support the device dsPIC33AK512MC510 and PKOBv4. The MPLAB X IDE, MPLAB XC-DSC Compiler, and X2C-Scope plug-in used for testing the firmware are mentioned in the Motor Control Application Firmware Required for the Demonstration section.

To get help on

• MPLAB X IDE installation, refer link
• MPLAB XC-DSC Compiler installation steps, refer link

If MPLAB IDE v8 or earlier is already installed on your computer, then run the MPLAB driver switcher (Installed when MPLAB®X IDE is installed) to switch from MPLAB IDE v8 drivers to MPLAB X IDE drivers. If you have Windows 8 or 10, you must run the MPLAB driver switcher in Administrator Mode. To run the Device Driver Switcher GUI application as administrator, right-click on the executable (or desktop icon) and select Run as Administrator. For more details, refer to the MPLAB X IDE help topic “Before You Begin: Install the USB Device Drivers (For Hardware Tools): USB Driver Installation for Windows Operating Systems.”

4.2 Setup: X2C-SCOPE

X2C-Scope is a MPLAB X IDE plugin that allows developers to interact with an application while it runs. X2C-Scope enables you to read, write, and plot global variables (for motor control) in real-time. It communicates with the target using the UART. To use X2C-Scope, the plugin must be installed. To set up and use X2C-Scope, refer to the instructions provided on the web page.

5. BASIC DEMONSTRATION

5.1 Firmware Description

The firmware version needed for the demonstration is mentioned in the section Motor Control Application Firmware Required for the Demonstration. This firmware is implemented to work on Microchip’s Digital Signal Controller (dsPIC® DSC) dsPIC33AK512MC510. For more information, see the dsPIC33AK512MPS512 Family datasheet (DS70005591).

This firmware targets high-speed sensorless trapezoidal commutation, with the ADC sampling and PWM switching frequencies configured to 40 kHz. Functional validation was performed using a 14‑pole motor, achieving stable operation up to 11,000 RPM under no‑load conditions. Operating at switching frequencies greater than 40kHz would require firmware/hardware modifications and has not been validated.

The Motor Control Demo application uses push button SW1 to start or stop the motor, push button SW2 to change the direction of rotation of the motor and a potentiometer to vary the speed of the motor. This application configures and uses peripherals like PWM, ADC, OP-AMP, CMP, DAC, UART etc.

Note:
The project may not build correctly in Windows OS if the Maximum path length of any source file in the project is more than 260 characters. In case the absolute path exceeds or nears the maximum length, do any (or both) of the following:

• Shorten the directory name containing the firmware used in this demonstration. If you renamed the directory, consider the new name while reading the instructions provided in the upcoming sections of the document.
• Place firmware in a location such that the total path length of each file included in the projects does not exceed the Maximum Path length specified.
  Refer to MPLAB X IDE help topic “Path, File, and Folder Name Restrictions” for details.

In addition to the Sparrow APM3115‑KV900, the firmware was tested on the following motors:

• 24V 3-Phase Brushless DC Motor - Hurst DMA0204024B101 (AC300022),
• 24V 3-Phase Brushless DC Motor - Hurst DMB0224C10002 (AC300020),
• 24V 3-Phase Leadshine Servo Motor (ELVM6020V24FH-B25-HD),
• 24V 3-Phase ACT Brushless DC Motor (ACT 57BLF01),
• 24V 3-Phase ACT Brushless DC Motor (ACT 57BLF02)
• 30V 3-Phase Anaheim Brushless DC Motor (BLY343S-30V-3000)
• 24V 3-Phase Linix Brushless DC Motor (36ZWN24),
• Johnson Electric low voltage EC motor (E11IHM)

5.2 Basic Demonstration

Follow the below instructions, step by step, to set up and run the motor control demo application:

1. Start MPLAB X IDE and open the project bldc.X (File > Open Project) with device selection dsPIC33AK512MC510.

   

2. Set the project bldc.X as the main project by right-clicking on the project name and selecting Set as Main Project as shown. The project bldc.X will then appear in bold.

   

3. Open mc1_user_params.h (bldc.X > Header Files) in the project bldc.X.

   • Firmware is by default configured to run in closed-loop speed control using a PI controller.
     • define the macro to CLOSED_LOOP 0 to enable open-loop duty control.
     • define the macro to CLOSED_LOOP 1 to enable closed-loop speed control using a PI controller.
     • define the macro to CLOSED_LOOP 2 to enable closed-loop current control using a PI controller.

     

   • Firmware is configured to run Sparrow APM3115-Kv900 brushless DC motor by default.
     • The Motors are tested under no load conditions. To achieve optimal performance under loaded conditions, the control parameters in the firmware may need additional tuning.

     

   • Current Control Configuration
     • When current feedback hardware is available and current‑control PI loops are required, define the macro ENABLE_CURRENT_CONTROL. This enables the use of current feedback signals and activates the current‑control PI loops in the control algorithm.
     • When current feedback hardware is not available, or when operating in voltage‑control mode only, undefine the macro ENABLE_CURRENT_CONTROL. In this case, current feedback is assumed to be unavailable and the system operates entirely in voltage‑control mode.
     • This configuration should be selected based on hardware capability (presence of current feedback sensors).

     

   • PWM Current Limiter Configuration
     • When current control is not enabled and DC bus current limiting is required, define the macro ENABLE_PWM_CURRENT_LIMITER This enables PWM‑based DC bus current limiting using the PWM CLPCI hardware feature.
     • When PWM‑based current limiting is not required, undefine the macro ENABLE_PWM_CURRENT_LIMITER No PWM‑based bus current limiting is applied. Note: This feature is automatically disabled when ENABLE_CURRENT_CONTROL is defined.
     • It is recommended to enable this feature when current control is disabled, to ensure bus and motor currents remain within board and motor limits.

     

   • When internal amplifiers are used for current amplification (referred to as internal op-amp configuration), define the macro INTERNAL_OPAMP_CONFIG

     

   • Otherwise, if external amplifiers are used for current amplification (referred to as external op-amp configuration), undefine the macro INTERNAL_OPAMP_CONFIG

     

4. Right-click on the project bldc.X and select Properties to open its Project Properties Dialog. Click the Conf:[default] category to reveal the general project configuration information. The development tools used for testing the firmware are listed in section 2.2 Software Tools Used for Testing the firmware.

   In the Conf:[default] category window:

   • Ensure the selected Device is dsPIC33AK512MC510.
   • Select the Connected Hardware Tool to be used for programming and debugging.
   • Select the specific Device Family Pack (DFP) from the available list of Packs. In this case, dsPIC33AK-MC_DFP 1.4.172 is selected.
   • Select the specific Compiler Toolchain from the available list of XC-DSC compilers. In this case, XC-DSC(v3.31) is selected.
   • After selecting Hardware Tool and Compiler Toolchain, Device Pack, click the button Apply

   Please ensure that the selected MPLAB® XC-DSC Compiler and Device Pack support the device configured in the firmware

   

5. Ensure that the checkbox Load symbols when programming or building for production (slows process) is checked under the Loading category of the Project Properties window.

   

   Also, go to Tools > Options , and

   

   Open the Embedded > Generic Settings tab and ensure that the ELF debug session symbol load methodology (MIPS/ARM) is selected as Pre-procesed (Legacy) from the drop down.

   

6. To build the project (in this case, bldc.X) and program the device dsPIC33AK512MC510, click Make and Program Device Main project on the toolbar

   

7. If the device is successfully programmed, LED1 (LD2) will be blinking, indicating that the dsPIC® DSC is enabled.

   

8. Run or stop the motor by pressing the push button SW1. The motor should start spinning smoothly in one direction in the nominal speed range. Ensure that the motor is spinning smoothly without any vibration. The LED LED2(LD3) is turned ON to show the button is pressed to start the motor.The specific motor was tested under no load conditions. To achieve optimal performance under loaded conditions, the control parameters in the firmware may need additional tuning.

   

9. The motor speed can be varied using the potentiometer (POT1).

   

10. Press the push button SW2 to change the direction of rotation of motor.

    

11. Press the push button SW1 to stop the motor.

Note:
The macros POLE_PAIRS, MAXIMUM_SPEED_RPM, and NOMINAL_CURRENT_PHASE_RMS are defined in the respective motor header files. Exceeding manufacture's specifications may damage the motor or the board or both.

5.3 Data visualization through X2C-Scope Plug-in of MPLAB X

X2C-Scope is a third-party plug-in in MPLAB X, which helps in real-time diagnostics. The application firmware comes with the initialization needed to interface the controller with the host PC to enable data visualization through the X2C-Scope plug-in. Ensure the X2C-Scope plug-in is installed. For more information on how to set up a plug-in, refer to either the Microchip Developer Help page or the web page.

1. To establish serial communication with the host PC, connect a micro-USB cable between the host PC and connector J16 on the development board. This interface is also used for programming.

2. Ensure the application is configured and running as described under section 5.2 Basic Demonstration by following steps 1 through 10.

3. Open the X2C-Scope window by selecting Tools>Embedded>X2CScope.

   

4. In the X2C-Scope Configuration window, open the Connection Setup tab and click Select Project. This opens the drop-down menu Select Project with a list of opened projects. Select the specific project bldc from the list of projects and click OK.

   

5. To configure and establish the serial communication for X2C-Scope, open the X2CScope Configuration window, click on the Connection Setup tab and:

   • Set Baudrate as 115200, which is configured in the application firmware.
   • Click on the Refresh button to refresh and update the list of the available Serial COM ports connected to the Host PC.
   • Select the specific Serial port detected when interfaced with the development board. The Serial port depends on the system settings

   

6. Once the Serial port is detected, click on Disconnected and turn to Connected, to establish serial communication between the Host PC and the board.

   

7. Open the Project Setup tab in the X2CScope Configuration window and,

   • Set Scope Sampletime as the interval at which X2CScopeUpdate() is called. In this application, it is every 25µs.
   • Then, click Set Values to save the configuration.

   

8. Click on Open Scope View (in the Data Views tab of the X2CScope Configuration Window); this opens Scope Window.

   

9. In the Scope Window, select the variables that must be watched. To do this, click on the Source against each channel, and a window Select Variables opens on the screen. From the available list, the required variable can be chosen. Ensure checkboxes Enable and Visible are checked for the variables to be plotted. To view data plots continuously, uncheck Single-shot. When Single-shot is checked, it captures the data once and stops. The Sample time factor value multiplied by Sample time decides the time difference between any two consecutive data points on the plot.

   

10. Click on SAMPLE, then the X2C-Scope window plots variables in real-time, which updates automatically.

    

11. Click on ABORT to stop.

    

    The X2C‑Scope plots of the back‑EMF signals Va, Vb, and Vc, the reconstructed neutral voltage, and the estimated commutation sector are shown below

    

    The image below shows the line voltage Vab and the A‑phase current.

    

6. REFERENCES:

For additional information, refer following documents or links.

1. AN1160 Application Note “Sensorless BLDC Control with Back-EMF Filtering Using a Majority Function”
2. MCLV-48V-300W Development Board User’s Guide (DS50003297)
3. dsPIC33AK512MC510 Motor Control Dual In-Line Module (DIM) Information Sheet (DS70005553)
4. dsPIC33AK512MPS512 Family datasheet (DS70005591)
5. MPLAB® X IDE User’s Guide (DS50002027) or MPLAB® X IDE help
6. MPLAB® X IDE installation
7. MPLAB® XC-DSC Compiler installation
8. Installation and setup of X2Cscope plugin for MPLAB X
9. Microchip Packs Repository

7. COMMON OBSERVATIONS:

1. If hardware overvoltage or overcurrent fault protection occurs repeatedly during motor operation, the protection can be disabled by removing resistor R200 and populating R198.

   

2. Capacitors C52, C53, and C54 in the phase voltage feedback RC filter are replaced with 200 pF, 50 V, 0603 capacitors for a maximum switching frequency of 40kHz.

   

   The image below shows the PWM AH signal, inverter A‑phase output, and the BEMF Va for motor phase A.

   

   The capacitance value is chosen to damp the oscillations as shown in the figure below, where the oscillations present in the yellow signal are attenuated in the green signal, which is the ADC input.