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If the motor is designed for 60 Hz and you intend to use it at 50 Hz, you must reduce the voltage so that you don't overexcite the core (iron). To achieve this, you will have to reduce the voltage to 200 Vac (i.e., volts per hertz V/Hz = constant). By doing this, realize that the nameplate power, torque and speed ratings will all be reduced. The power will be 83%, the torque will be 69% and the speed will be 83%. Since this is an induction motor, there will be no pole slipping as stated above. As long as you don't exceed the temperature rise rating of the machine, the life span of the motor will not be reduced.
Tags: Power supply, 60Hz 50Hz
One reason why the converter is unable to feed the peak current directly is because of its own source (output) impedance limitations. One could consider feed-forward technique to address this problem.
Let me assume that this is Lsource, say it is predominantly inductive. In that case, the feed-forward voltage required to overcome this effect is dff, where
vff = Lsource*delta(Ipk)/deltat
Where delta(Ipk)/deltat is the rate of change of peak current.
dff = vff/Vdcmax
where
dff is the dutycycle required to produce vff
Thus,
Dtot = Derr+dff
Where
Dtot = total dutycycle fed to the switch
Derr = dutycycle from the error controller
Let me assume that this is Lsource, say it is predominantly inductive. In that case, the feed-forward voltage required to overcome this effect is dff, where
vff = Lsource*delta(Ipk)/deltat
Where delta(Ipk)/deltat is the rate of change of peak current.
dff = vff/Vdcmax
where
dff is the dutycycle required to produce vff
Thus,
Dtot = Derr+dff
Where
Dtot = total dutycycle fed to the switch
Derr = dutycycle from the error controller
Tags: Converter, Power supply
Basically higher switching frequency allows smaller magnetic cores to be used with fewer turns. But often you are then constrained by the available winding space for your copper wire. While a toroidal core is the ideal shape for magnetic efficiency, giving the best ratio of Ae/le, E & I cores are far more practical and cheaper to wind. In addition with off-line swichers for example, you have to compromise on best winding arrangements to achieve lowest leakage inductance for safety margin in creepage and clearances. Primary and secondaries are then bobbin wound with deep plastic cheeks between primary and secondaries to provide the necessary insulation barriers to meet a 4kV safety flash test.
Switching loss will go up with frequency as you would expect, requiring faster semiconductors and gate drive circuitry. Then you would probably have to slow down your edges to reduce EMC, trading one against the other.
Hysteresis and eddy current loss in the ferrite will increase with frequency and core flux density as will the ac resistance or skin effect of your wire. This is offset by less turns and less ferrite and working at lower flux density and the use of Litz wire, (if you are very desperate for efficiency).
Switching loss will go up with frequency as you would expect, requiring faster semiconductors and gate drive circuitry. Then you would probably have to slow down your edges to reduce EMC, trading one against the other.
Hysteresis and eddy current loss in the ferrite will increase with frequency and core flux density as will the ac resistance or skin effect of your wire. This is offset by less turns and less ferrite and working at lower flux density and the use of Litz wire, (if you are very desperate for efficiency).
Tags: Power supply