Predictive pulse width modulation for an open delta H-bridge driven high efficiency ironless permanent magnet machine
View Patent ↗Embodiments of the present method and system permit an effective method for determining the optimum selection of pulse width modulation polarity and type including determining machine parameters, inputting the machine parameters into a predicted duty cycle module, determining the optimum polarity of the pulse width modulation for a predicted duty cycle based on a pulse width modulation generation algorithm, and determining the optimum type of the pulse width modulation for a predicted duty cycle based on the pulse width modulation generation algorithm.
1. A method for determining a predictive duty cycle that is able to determine the magnitude and pulse width of an H-bridge pulse width modulation that is used to drive a machine motor, comprising:
determining one or more machine parameters;
inputting the machine parameters into a predicted duty cycle module;
determining the optimum polarity of the pulse width modulation for a predicted duty cycle based on a pulse width modulation generation algorithm; and
determining whether the pulse width modulation is unipolar or bipolar for a predicted duty cycle based on the pulse width modulation generation algorithm,
wherein the pulse width modulation generation algorithm is
d
prediction
(
θ
elect
)
=
(
E
emf
(
T
magnet
,
rpm
)
·
sin
(
θ
elect
)
+
i
ref
(
θ
elect
)
R
s
(
T
winding
)
+
L
·
ⅆ
i
ref
ⅆ
t
)
Vbus
,
wherein E emf (T magnet ,rpm) is the back emf of the machine as a function of the magnet temperature and speed, θ elect is the electrical angle for the machine during that particular duty cycle, I ref is an input quantity of reference current, i.e., the amount of current that the processor wants to get out of that particular duty cycle, R s is the phase resistance of the machine and is a known input parameter, T winding is the temperature of the windings in the coil, and is also a known input parameter, L is the inductance of the inductor and is also an input parameter, and Vbus is the supply voltage of the inverter, and is a quantity that is measured by an analog-to-digital converter.
2. A system for determining a predictive duty cycle that is able to determine the magnitude and pulse width of an H-bridge pulse width modulation that is used to drive a machine motor, comprising:
means for determining one or more machine parameters;
means for inputting the machine parameters into a predicted duty cycle module;
means for determining the optimum polarity of the pulse width modulation for a predicted duty cycle based on a pulse width modulation generation algorithm; and
means for determining whether the pulse width modulation is unipolar or bipolar for a predicted duty cycle based on the pulse width modulation generation algorithm,
wherein the pulse width modulation generation algorithm is
d
prediction
(
θ
elect
)
=
(
E
emf
(
T
magnet
,
rpm
)
·
sin
(
θ
elect
)
+
i
ref
(
θ
elect
)
R
s
(
T
winding
)
+
L
·
ⅆ
i
ref
ⅆ
t
)
Vbus
,
wherein E emf (T magnet ,rpm) is the back emf of the machine as a function of the magnet temperature and speed, θ elect is the electrical angle for the machine during that particular duty cycle, I ref is an input quantity of reference current, i.e., the amount of current that the processor wants to get out of that particular duty cycle, R s is the phase resistance of the machine and is a known input parameter, T winding is the temperature of the windings in the coil, and is also a known input parameter, L is the inductance of the inductor and is also an input parameter, and Vbus is the supply voltage of the inverter, and is a quantity that is measured by an analog-to-digital converter.
3. A computer-readable medium for determining a predictive duty cycle that is able to determine the magnitude and pulse width of an H-bridge pulse width modulation that is used to drive a machine motor, comprising:
means for determining one or more machine parameters;
means for inputting the machine parameters into a predicted duty cycle module; and
means for determining the optimum polarity of the pulse width modulation for a predicted duty cycle based on a pulse width modulation generation algorithm; and
means for determining whether the pulse width modulation is unipolar or bipolar for a predicted duty cycle based on the pulse width modulation generation algorithm,
wherein the pulse width modulation generation algorithm is
d
prediction
(
θ
elect
)
=
(
E
emf
(
T
magnet
,
rpm
)
·
sin
(
θ
elect
)
+
i
ref
(
θ
elect
)
R
s
(
T
winding
)
+
L
·
ⅆ
i
ref
ⅆ
t
)
Vbus
,
wherein E emf (T magnet ,rpm) is the back emf of the machine as a function of the magnet temperature and speed, θ elect is the electrical angle for the machine during that particular duty cycle, I ref is an input quantity of reference current, i.e., the amount of current that the processor wants to get out of that particular duty cycle, R s is the phase resistance of the machine and is a known input parameter, T winding is the temperature of the windings in the coil, and is also a known input parameter, L is the inductance of the inductor and is also an input parameter, and Vbus is the supply voltage of the inverter, and is a quantity that is measured by an analog-to-digital converter.