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1. FIELD ORIENTED CONTROL GENERATOR
2. FIELD ORIENTED CONTROL DRIVER
3. FIELD ORIENTED CONTROL SOFTWARE
4. FIELD ORIENTED CONTROL CODE
5. FIELD ORIENTED CONTROL LICENSE

FIELD ORIENTED CONTROL SOFTWARE

The IC works with incremental (quadrature) encoders or Hall signals for position feedback, with a field-oriented current control using pulse width modulation (PWM), a velocity control loop, and a position-control loop and ramp controllers, the software can define the complete servo controller stack.

FIELD ORIENTED CONTROL DRIVER

The 12 mm ×x 17 mm IC (Figure 1), includes a complete servo controller software stack, while the integrated gate driver can support a wide range of N-channel power switches for 24 V motors. KG, (Hamburg, Germany) offers their TMCC160 MotionCookie, an integrated microsystem which includes a 3-phase servo-gate driver suitable for up to 24 V and 1 A gate-drive current. For example, TRINAMIC Motion Control GmbH & Co. Q: If a designer wants to implement FOC, does he or she have to pull together all the hardware components and the algorithms in firmware or software?Ī: Of course not many vendors offer complete FOC subsystems or systems on one or a few ICs.

Part 2 now looks at some implementations, again without the underlying math.

FIELD ORIENTED CONTROL GENERATOR

3ph generator (Vdc, |V|, ∟V,fstator in, 6 gate drives out) Polar Transform (VD and VQ in, |V| and ∟V out).Magnetic Flux PI Controller (ΔFlux in (ID* - ID), VD out).Torque PI Controller (ΔTorque in (IQ* - IQ), VQ out).Magnetic Flux setpoint Controller (variety of inputs, Vdc, frotor, IQ* etc, ID* out).Given any two motor phases, convert to rectilinear, then rotate to rotor axis. 3ϕ measured current -> 2ϕ (D-Q axis) transformation.We will forgo sensorless control as zero speed response is critical.Ĭontroller components - Motor Control Electronics Handbook ISBN 0-07-066810-8 Fig 8.41 Measured Rotor Speed - via incremental encoder.For overrated torque overfluxing may be needed. Magnetic Flux - notionally constant, however at high speeds it will need to be reduced as the bus voltage is reached (thus field weakening), also while at low torque may be reduced to improve motor efficiency.Torque - the position of the accelerator (after being scaled and rate limited).The greater degree that the motor can be modeled to, the greater the degree of accurate control.įor the EV application, where torque control is required, the vector controller is somewhat simplified as it does not require a overall speed loop. The indirect method estimates the magnetic flux from the applied voltage and resultant current via a model of the motor. The direct method requires that the flux in the rotor-stator gap be measured.

Of the two types of vector control - direct and indirect - we will concentrate on indirect means. Angle only makes sense between 0-360degrees, so the integral just resets instead of going out of range.įield Oriented or Vector control separates the motor current into two components, the field producing current and the torque producing current.

Slip Angle is the time integral of Slip frequency. So, for a given motor, and Torque and Flux currents, the motor will be slipping at a determinable frequency. Slip frequency depends on the ratio of Torque current vs Flux current, and Motor Characteristics (rotor time constant), as seen in the above equation.Īs the ratio between torque vs flux (Iq vs Id) decreases, the gradient of the line in the linear region becomes steeper, and thus the slip frequency for a given torque reduces. Going beyond this linear region can cause excessive current, for little gain in torque. Induction motors are usually operated in the relatively linear region (within just a few percent) of the applied electrical frequency. Secondly, consider the typical induction motor curve (at fixed frequency and voltage):

FIELD ORIENTED CONTROL CODE

Explanation and sample code available here: įirst the definition of slip needs to be understood, wikipedia has a good definition of slip which you should read. This can be easily calculated in code with numerical integration (e.g. It can be shown that (ref: pg 278 Motor Control Electronics Handbook by Richard Valentine ISBN 0 -07-066810-8): Lr - Rotor Total Inductance (H) (H = Wb/A = Vs/A = Ωs)

FIELD ORIENTED CONTROL LICENSE

Note that this document also has details on one possible technique for Rotor Time Constant correction (also on page 25, at the bottom).Ī good IFOC intro and source code is available here (thanks to Paul for pointing this out on evtech): (Note: the license prevents the code being used on anything except Microchip hardware). FYI - Given the state of the Wikipedia FOC topic, we should probably be contributing to it: Įven better, see (Equation (2-37) on pg 25 is the one that nails the calculation needed for the rotor flux angle calculation).