Engineering by Technology - Motor Control
 

Project

Control Electronics

Application

Diesel-Fired Military Tent Heater

Customer Need

MIL-compliant electronic control of all aspects of a military tent heater including start/stop sequence, closed-loop temperature control, fuel/air mixture, fan motor control, power management and battery charging with system power provided by a Thermo-Electric Generator (TEG). Additional requirements included a remote temperature sensor and user-set point input, with CO monitor.

AVID's Solution

Our engineering services extended beyond board and firmware design to satisfy all of the needs listed above as it included system level operational aspects, use cases, diagnostics, addressing unit to unit variations of the burners and TEGs, and corner case conditions. AVID was responsible for the complete board level design, embedded and system firmware, and system verification to Military requirements. AVID assisted in electronics packaging, cable harness design, and release to manufacturing. We also created a real-time executable for the PC that allows test engineers to monitor and modify run-time parameters during system test without the need to reprogram the system.

Value Added or Technologies Applied

  • System Operation and Use Case
  • Control Architecture
  • Hardware and Firmware Design and Implementation
  • Prototyping and Validation
  • PC Application Development
  • System Qualification Support
  • Manufacturing Engineering
 
 

Project

Battery-Powered Control Circuitry

Application

Prosthetic Limb

Customer Need

Amputees have the ability to create myo-electric signals by flexing muscles which can be sensed and used to control the movement of prosthetic limbs. Sensors detect these very low level signals which require electronics to control motors for movement. These circuits must be small, accurate, and able to run from battery power.

AVID's Solution

AVID developed a very compact analog circuit which amplifies the myo-electric signals, and outputs control signals suitable to accurately control a motor. These motors may be used to control the opening and closing of a mechanical hand or may rotate a mechanical elbow joint.

Value Added or Technologies Applied

  • Myo-Electric Sensing and Requirements
  • Hardware Design and Implementation
  • Prototyping and Validation
  • Low-Volume Production
 
 

Project

Control Electronics

Application

Home Air Filter/Purifier

Customer Need

As a high end home air filter, this new product required intelligence for functions such as variable fan speed control, dust sensing, filter life monitor, remote control interface. The system has the ability to automatically adjust the fan speed based on the dust in sampled air in addition to a user settable manual mode. A special high speed “turbo” mode is also included for maximum air cleaning. A user panel of LEDs and pushbuttons provides for system monitor and user adjustment. Low cost, high reliability is a requirement.

AVID's Solution

A microprocessor-based system was implemented with PWM-controlled output to the fan motor. The micro monitored a dust sensor as well as the user pushbuttons. Control loops were implemented in the firmware for fan speed control. The firmware also controlled the operating modes, kept track of filter life, illuminated user panel LEDs and interfaced via an IrDA port to a remote control device and allows for field upgrades.

Value Added or Technologies Applied

  • Electronics Specification
  • Hardware/Firmware Design
  • Prototype and Validation
  • Manufacturing Engineering Support, Production Test Procedure
 
 

Project

Motor Controller

Application

Commericial Vehicle Electronics

Customer Need

An 8HP 3-Phase Motor is used to drive an air compressor for a large hybrid vehicle breaking system. A motor controller is required to control motor speed with a 300VDC to 420VDC input bus. The product must meet automotive requirements for reliability and ruggedness.

AVID's Solution

Challenges for this project included high instantaneous switching currents, critical timing for phase switching, thermal protection, and addressing the parasitic parameters of the switching devices and other system components. Excessive noise must be eliminated as it causes errant operation and ultimately component failures. Three half bridge drivers commutate at 200 KHz. A high side PWM switches at 20 KHz to control speed. The design is partitioned into two boards; a low voltage digital control board and a high voltage driver board. The LV board comprises a DSP for system control, DC/DC supply, inputs for motor speed, pressure and temperature, and outputs for the PWM drive and valve control. The HV board contains three half bridge IGBT low side drivers and FET high side drivers. Low voltage power isolation is needed for the FET drive and sensor circuits. Thermistor temperature sensing and protection was included for each phase. The layout required hand-crafted planning to accommodate the ~20A currents, isolation requirements, and tight loops to minimize system noise and emissions.

Value Added or Technologies Applied

  • Review and Re-Design of Customer Circuitry to Address Problems with Operation, Noise, and Component Failures
  • Parallel Paths for Different System Architectures to Determine Optimum Implementation
  • Prototyping and Bench Testing of Critical Sections of Each
  • Hand-Crafted Layout and Board Partitioning Optimization
  • Final Design Implementation, PCB Layout, Prototype, and Bench Testing
  • Engineering Build of 20+ Units for Customer Validation and Field Testing
  • AVID Support of the Customer Testing, Validation, Field Trials, Production Readiness