Projects completed and value addition. controltrix.com

PROJECT GUIDE
Extensive experience in sensors and control pertaining to motion control and power
electronics allows us to crack your tough specifications and tackle challenging problems.
The following sections are a representative description of various past projects that have
been undertaken and the value addition that has been possible.

www.controltrix.com consulting@controltrix.com all rights reserved
1

1.0.0 MOTION SENSING AND CONTROL
Extensive experience with various types of motors and electromagnetic sensors and
actuators allows us to tackle a large variety of problems. Below is a small representative
list of past work and where value may be added.

2

1.1.0 PERMANENT MAGNET MACHINES

1.1.1 FIELD ORIENTED CONTROL / VECTOR CONTROL

Salient features (fairly common knowledge)

 Precise and fast torque and speed control
 Optimal motor utilization (most bang for the buck)
 Useful for transient and fast changing loads such as washing machines, power tools
 Low noise operation
 Allows the motor to be operated beyond its rated speed
 Sensored and sensor less operation possible
 Traditional sensor less operation is based on estimation using sliding mode controller or
PLL type observer
 Space vector modulation
 Typically 2 quadrant bi directional motoring operation

More…..

 Remove any performance degradation due to low grade input power supplies with large
ripple content in the input voltage. (such as front end rectifier, Power factor correction
etc)
 KALMAN filter based position and speed estimation for sensor less mode for accurate
position and velocity control
 16 bit computationally economical fixed point implementation of Kalman filter
 4 quadrant operation. (regeneration/ braking and motoring operation) within the same
system
 Dead time compensation for smoother operation
 Single shunt current sense based implementation for low cost applications
 Sensor less smooth and reliable startup
 Operation beyond the rated speed possible with field weakening

3

1.1.2 DIRECT TORQUE CONTROL

 Almost identical performance as with field oriented control. (refer 1.0.2)
 Much Less amount of computation. (suitable for low cost application)
 Sensored and Sensor less operation

More….
 Refer 1.1.1 (under value addition) same features apply

4

1.2.0 BRUSH DC MOTOR

 Speed control with encoder
 Position control with encoder
 Torque control with current sense
 Regenerative and dynamic braking (4 quadrant operation)

More…..

 Sensor less Speed control (without encoder/resolver) e.g. fans ,pumps etc
 Sensor less Position control (without encoder/resolver) e.g. servo drives ,robots, toys
 Accurate reliable and smooth position /speed estimation and control using KALMAN
filter/ Luenberger and Gopinath observer

5

1.3.0 BRUSHLESS DC MOTOR

 Speed control with hall effect /encoder (pumps, fans, compressors etc)
 Torque control/Torque mode (electric bicycles)
 Regenerative and dynamic braking (4 quadrant operation)with most energy efficient way
 Speed control (open/closed) loop in sensor less mode

More…..

 KALMAN filter based speed and position estimation based control
 Sensored hall effect based operation with high immunity to PWM noise (useful for
electric vehicle applications, High current and Hi power drives)
 Improved reliability in sensor less mode of operation using filtering
 Operation beyond the rated speed of the motor
 Low audible noise 6 step operation (sensored and sensor less) (e.g. fans , blowers etc )
 Demonstrably lower losses

6

1.4.0 THREE PHASE AC INDUCTION MACHINES

Sections 1.4.x pertains to 3 phase AC induction machines

1.4.1 V/F CONTROL

 Scalar control
 Low noise
 Low cost
 Easy to implement

More…..

 Dead time compensation to ensure low distortion in current waveform
etc)
 Minimize noise/harmonics due to low grade input voltage

 Dynamic/regenerative braking /(4 quadrant operation)
 Limiting the start current to manageable levels without significantly reducing startup
torque (white goods ,solar pumps )

1.4.2 FIELD ORIENTED CONTROL / VECTOR CONTROL

 Precise and fast torque and speed control
 Optimal motor utilization (most bang for the buck)
 Useful for transient and fast changing loads such as washing machines, power tools
 Low noise operation
 Allows the motor to be operated beyond its rated speed
 Sensored and sensor less operation possible
 Traditional sensor less operation is based on estimation using sliding mode controller or
PLL type observer

7

 Typically 2 quadrant bi directional motoring operation
 Operation beyond the rated speed possible with field weakening

More…..

etc)
 KALMAN filter/other filter based position and speed estimation for sensor less mode for
accurate position and velocity control
 Computationally inexpensive 16 bit fixed point implementation of KALMAN filter
 4 quadrant operation. (regeneration/ braking and motoring operation) within the same
system
 Dead time compensation for smoother operation
 Single shunt current sense based implementation for low cost applications
 Sensor less smooth and reliable startup

1.4.3 DIRECT TORQUE CONTROL

 Almost identical performance as with field oriented control. (refer 1.0.2)
 Much Less amount of computation. (suitable for low cost application)
 Sensored and Sensor less operation

More…..

 Refer 1.4.1 (under value addition) same features apply

8

1.5.0 SERVO MOTOR CONTROL

 Hi bandwidth position and velocity control (for machine tools, robots)
 Hi bandwidth torque control
 Reduced tracking error
 Backlash error removal
 Dead time compensation for reduced distortion
 Repetitive control for periodic load and periodic trajectories to minimize tracking error
 Smooth and low noise operation

9

1.6.0 STEPPER AND SWITCHED RELUCTANCE MOTOR

 Micro stepping for smooth control of stepper motor
 Switched reluctance motor calculations and control

10

1.7.0 SINGLE PHASE AC INDUCTION MOTOR

 Inverter control of single phase AC induction motor
 Limiting the start current to manageable levels without significantly reducing startup
torque (white goods ,solar pumps )
 Retrofitting existing solution

11

1.8.0 ELECTROMAGNETIC LINEAR ACTUATOR CONTROL

 Design Control system for linear actuator (position ,speed and force control)
 Sensor replacement algorithms using self sensing
 Advanced filtering and sensor fusion algorithms

12

1.9.0 LINEAR MEASUREMENT USING ACCELEROMETER DATA

 Improved accuracy in speed and position estimation
 Reduced effects of drifts using advanced filtering and sensor fusion algorithms
(Smart phone apps such as virtual measuring tape, inertial navigation system in toys,
unmanned aerial vehicles etc.)
 Compensate effect of gravitation on the fly
 Gesture recognition (smart phone apps)

13

1.10.0 ROTATIONAL MEASUREMENT USING GYROSCOPIC DATA

 Improved accuracy in angular speed and angular position estimation
 Reduced effects of drifts using advanced filtering and sensor fusion algorithms (Smart
phone apps such as virtual measuring tape, inertial navigation system in toys,
unmanned aerial vehicles etc.)
 Gesture recognition (smart phone apps)
 Handling cross coupled states
 Compensation for curvature and rotation of earth in inertial navigation systems
 Estimation of radius of circular motion (gyroscopic + accelerometer data)
 Advanced Filtering to ensure accurate estimate of radius

14

2.0.0 POWER CONTROL
Extensive experience in power conversion allows us to tackle a wide array of problems to
meet your stringent performance requirements. The following is a representative list of
various past projects and value addition. In general

1. Meeting performance specs

2. Simulation for visulati

3. Code generation for fixed point DSP implementation

4. Problem solving

15

2.1.0 DC-DC DIGITAL PWM SWITCHED MODE CONVERTERS

 Optimal performance
 Stability analysis
 Large number of topologies
 Excellent line and load regulation

16

2.2.0 SINGLE PHASE DIGITAL POWER FACTOR CORRECTION

 Near unity power factor for Continuous conduction mode operation
 Improved voltage response to fast changing load
 Achieving low THD and high PF @ Low load (discontinuous conduction mode) (ever
stringent specs) e.g. 10% THD @ 10% load
 Advanced non linear techniques to improve THD in discontinuous mode
 Consistent performance across a wide input and output voltage range
 Single phase and interleaved operation
 Fixed on-time hysteresis PFC control

17

2.3.0 THREE PHASE DIGITAL POWER FACTOR CORRECTION

 Bidirectional power flow
 Near unity power factor for Continuous conduction mode operation
 Improved voltage response to fast changing load
 Unbalanced voltage source handling
 Voltage following
 Sine table look up with PLL for low THD

18

2.4.0 SINGLE CYCLE CONTROL PFC SW IMPLEMENTATION

 Emulate in software single cycle control PFC
 Lower number of ADC required
 Phase Voltage measurement not required
 Only unidirectional operation
 Unbalanced voltage source handling
 Voltage follower operation

19

2.5.0 PURE SINE WAVE INVERTER (HOME UPS,BACKUP)

 Low distortion sine wave under all types of load ( rectifier, inductive, capacitive)
 Low overshoot and undershoot
 Dead time compensation
 Inductor saturation
 Syncing with AC source and switchover
 Sine table lookup ,variable frequency ,amplitude and phase
 Low tracking error

20

2.6.0 DC-DC CONVERTER/BATTERY CHARGERS

 Various topologies full bridge, push pull, buck, boost, buck boost , fly back, forwardly
resonant series/parallel
 Low overshoot/undershoot
 Current source and voltage source
 Current sink and voltage sink
 Controlled regulation operation
 Voltage mode control, current mode control, peak current mode control
 Remote sense
 Paralleling/load sharing
 Optimizing thermal stress by load sharing based on temperature
 Ideal diode software implementation
 Charge profiling, charge termination and state of charge control

21

2.7.0 POWER LED CONTROL

 Digital dimming ~ 400 hz led is turned on and off
 Fast current rise
 Almost any DC –DC converter topologies
 Almost perfect square wave current wave shape
 Minimal spikes/overshoots/undershoots @ start and stop of the on –time

22

2.8.0 HID LAMP BALLAST CONTROL/WELDING

 Constant current control for negative resistance load

23

2.9.0 HYBRID OFF GRID/ GRID CONNECTED INVERTER

 MPPT solar PV inverter for feeding into the grid
 SCR/thryristor based inversion
 PLL and synching with the AC grid
 Current source topology
 Lower computation

24

2.10.0 MICRO GRID/ DISTRIBUTED GENERATION

 Synchronization of multiple AC sources
 Black start
 Limiting current based on power electronic devices
 Protection schemes

25

2.11.0 DIGITAL SLOPE COMPENSATION

 For peak current mode control
 Dynamic Slope compensation using digital calculations instead of a constant ramp
addition
 Optimal choice of slope for any given operating conditions
 Best convergence
 Minimal degradation to voltage mode control (contrast traditional slope compensation)
 Useful for wider range input and output voltage systems

26

2.12.0 THRYRISTOR/SCR BASED 3PHASE / 1PHASE POWER
CONTROL

 Motor drives
 3phase and 1phase SCR/Thryristor phase angle control
 Validation of conditions
 Starters for motor
 Light dimming
 Harmonic analysis

27

2.13.0 TEMPERATURE CONTROL AND THERMAL
MANAGEMENT

 Minimum overshoot/undershoot
 Smooth continuous control emulated through on off
 Modeling using MATLAB and obtaining predictable results

28

Projects completed and value addition. controltrix.com

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