Motor Control

 Applications    Architectures  

Motor control has been the domain of real time, deterministic microcontrollers for quite some time. New mandates for power efficiency and new security requirements are increasing the complexity of motor and motion control applications. This new algorithm complexity drives performance and power efficiency requirements to new levels. To meet these new requirements it's only natural to use a microcontroller or microprocessor with a higher clock rate. But to achieve these higher clock rates, manufacturers of microcontroller and microprocessors typically deepen the instruction pipe length; add predictive branch mechanisms, maybe even instruction and data caches, sacrificing determinism in the process. When an interrupt occurs on these new processors the time to service the interrupt can increase to tens if not hundreds of clock cycles. Suddenly your application is no longer deterministic. This new variability in the control algorithm does have consequences and can be critical in certain applications. The only way to achieve determinism at extremely high computational levels is to replace your critical firmware algorithms with hardware acceleration.

Microsemi has 4 different product families to service the different requirements of motor control applications. From simple high speed PWM generation in a low power and reliable Igloo FPGA to the world's most secure, reliable, and low power FPGA SmartFusion2 Microsemi has your motor control solutions covered.

Microsemi Motor Control solutions can address a number of applications in different markets:

• Robotic arms in industrial environments
• Missiles in military applications
• Infusion pumps in medical applications

Robotic arms in industrial environments

Secure Protocols and Reliable motor control can be achieved with Microsemi SoC FPGA's. Additionally, multi-axis control and synchronization can occur all in a single chip with nanosecond precision, lowering costs, while increasing power efficiency at the same time. Reducing the number of components has an additional benefit to system reliability.

Missiles in military applications

Missiles fly fast. The short time to target demands that Fin control electronics have high performance capabilities. Given the extreme function a missile performs, it is an absolute requirement that all components that are sourced for a missile are secure in their chain of custody. In other words, supply chain assurance is just as critical to Missile designers as is being able to control the flight surfaces of said missile. Microsemi FPGA's and SoC FPGA's can deliver performance, security, and reliability all in a single chip small form factor.

Infusion pumps in medical applications

Low power, high reliability, secure patient data, these are all the things we want when we are being cared for. So let Microsemi SoC's FPGAs take care of your challenging medical designs with the world's most secure, reliable single chip SoC FPGA.

SmartFusion Motor Controller IC

Ideal platform to partition software & hardware architecture requirements

The SmartFusion family is the ideal platform to partition your software and hardware architectural requirements from the very beginning of the design cycle. The embedded ARM Cortex-M3 allows your software team to focus on the system layer and application layer algorithms. The programmable analog and FPGA gives your hardware team access to an array of different silicon features for extremely fast hardware acceleration / co-processing crucial in offloading the Cortex-M3 thus providing more overhead to accomplish more control functionality within a single platform, scalable across numerous applications.

As customers rely more and more on electronic systems to perform their job functions, the manufacturers of these systems are becoming increasingly governed by safety standards. These standards are to ensure that safety critical systems adhere to guidelines that prevent the equipment from causing harm through normal usage. Designers must ensure their systems provide functional safety, which is generally defined as "freedom from unacceptable risk of physical injury or of damage to the health of people, either directly or indirectly as a result of damage to property or to the environment." For more details on how Microsemi cSoCs provide an ideal platform for the implementation of designs incorporating functional safety, see http://www.microsemi.com/soc/products/solutions/safetycritical/default.aspx.

Motor Control Requirement #1: Embedded MCU: ARM Cortex-M3
Optimized for power consumption

Motor/Motion Control Functions

• Task management & algorithm execution
• Communicate with peripherals & host system
• System Connectivity

Device Specifics

• 100MHz
• 10/100 Ethernet MAC, SPI, I2C, UART, 32-bit Timers
• Up to 512 KB flash and 64 KB of SRAM, External memory controller
• 8-channel DMA controller, Up to 41 MSS I/Os

Requirement #2: Sense & Control: Programmable Analog
Full Analog Input & Output

Motor/Motion Control Functions

• Voltage & Current monitoring
• Temp monitoring

Device Specifics

• 12-bit (SAR) ADCs @ up to 600 Ksps
• Up to ten 15 ns high-speed comparators
• Up to 32 analog inputs and 3 outputs
• MCU offload through Analog Compute Engine

Requirement #3: Product Differentiator: Flash FPGA Logic
Hardware acceleration / math co-processing

Motor/Motion Control Functions

• Offload computational/cycle intensive algorithmic routines
• Utilize hardware as extremely fast & efficient subroutines
  • Configurable PWMs for speed, power or footprint requirements
  • PID block, Commutation logic, Park & Clarke transforms
  • Quadrature Encoder/HALL sensor logic for speed and position
  • Cordic block, State observers

Device Specifics

• 350 MHz logic performance
• Embedded Memory: SRAMs and FIFO

Performance Comparison

Function	CPU	FPGA	Percentage Gain
256-point 16-bit radix-4 FFT	326us	11us	29x Improvement

Implementation Example of architectural partitioning:
Block Commutation Implementation - Single Motor

Parameter in SmartFusion A2F200	Utilization
PWM Switching Frequency	8KHz (125us)
Cortex-M3 loading	5%
FPGA Logic Usage	87%

Implementation Example of architectural partitioning:
Sinusoidal Closed-Loop Implementation - Single Motor

Parameter in SmartFusion A2F200	Utilization
Code Size	61 KB
MSS Frequency	75 MHz
PWM Switching Frequency	20 KHz
MSS Utilization Rate/Time for Sine Commutation Logic	17 us (34% of PWM period)
CFPGA Operating Frequency	75 MHz
FPGA Fabric Utilization	3909 Core Tiles (85%)

Implementation Example of architectural partitioning:
Field Oriented Control - Hall Implementation - Single Motor

Function in SmartFusion A2F200	Utilization
Code Size	61 KB
MSS Frequency	75 MHz
PWM Switching Frequency	10 KHz
MSS Utilization Rate/Time for FOC Logic	40 us (80% of PWM period)
FPGA Operating Frequency	75 MHz
FPGA Fabric Utilization	4219 Core Tiles (92%)

Algorithm	Description	Availability
Trapezoidal (block commutation) - Open Loop	Standard algorithm for controlling DC Motors	Now
Trapezoidal (block commutation) - Closed Loop	Same as above but includes PID controller (Proportional-Integral-Derivative controller) closed loop for more accurate control	Now
Sinusoidal - Closed Loop	This design has both Sine and Sine + 3rd Harmonic injection PWM generation	Now
Field Oriented Control - Hall	Advanced algorithm.	Now
Field Oriented Control - Encoder	Advanced algorithm (allows the use of cheaper motors).	Now

Putting it together: Monolithic IC, Multi-Axis Motor Controller
Single device scalable across multiple platforms

Embedded MCU: ARM Cortex-M3 System Layer Tasks Port your Complex Algorithms Implement System Management Code & Parameter Storage Communication Protocols Sense & Control: Programmable Analog Voltage & Current Monitoring Temperature Monitoring Comparators to catch faults Differentiation: Flash FPGA Fabric Hardware Acceleration for computational portion of algorithms PID, PWM, FFT, FIR, Inverse Clarke Hardware acceleration of critical tasks Customized protocols & communication I/O Expansion

SmartFusion Dual Motor Control Kit The SmartFusion Dual Motor Control Kit from Microsemi leverages the flexibility and ease-of-use of the SmartFusion platform with TRINAMIC's IC drivers for both BLDC and stepper motors to bring a solution for your motor control prototyping needs. The kit includes a SmartFusion Evaluation board and the motor control daughter board along with two motors to enable immediate development for your applications.

• Intellectual Property — Required intellectual property (IP) depends on the application requirements
  • CorePWM: The essential IP is the PWM. Microsemi offers this robotic 8-channel PWM IP module, which is ready for plug-n-play development.
  • ARM® Cortex™-M3: Embedded in SmartFusion mixed signal FPGAs
  • 8051 Cores: 8051 compliant IP with peripheral IP available
  • CAN IP: Provides easy integration benefits to support CAN interface that is widely deployed in the industrial control applications.
  • SmartFusion IP cores
  • Fusion IP cores