Comprehensive smart-clamp strategy for inverter systems
A current command module is configured to, based on a motor torque request for an electric motor of the vehicle, generate a d-axis current command for the electric motor and a q-axis current command for the electric motor. A voltage command module is configured to generate voltage commands based on the d-axis current command and the q-axis current command. A switching control module is configured to: based on the d-axis current command and the q-axis current command, determine a first duty cycle command for a phase of the electric motor; generate a second duty cycle command based on the first duty cycle command, a predetermined minimum period to transition switches of an inverter module from OFF to ON, a predetermined switching period, a predetermined deadtime period when both of the switches are OFF before one of the switches is turned ON, and whether a current of the phase is positive.
1. An electric motor control system of a vehicle, comprising:
a current command module configured to, based on a motor torque request for an electric motor of the vehicle, generate a d-axis current command for the electric motor and a q-axis current command for the electric motor;
a voltage command module configured to generate voltage commands based on the d-axis current command and the q-axis current command;
a switching control module configured to:
based on the d-axis current command and the q-axis current command, determine a first duty cycle command for a phase of the electric motor;
generate a second duty cycle command directly based on the first duty cycle command, a predetermined minimum period to transition switches of an inverter module from OFF to ON, a predetermined switching period, a predetermined deadtime period when both of the switches are OFF before one of the switches is turned ON, and whether a current of the phase is positive or negative,
wherein the switches are connected between an energy storage device and the phase of the electric motor; and
based on the second duty cycle command, control switching of the switches the inverter module and control application of power from the energy storage device to the phase of the electric motor.
2. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is positive and the first duty cycle command is greater than
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
,
but less than
(
Ts
(
Tdead
+
Tmin
)
/
2
)
Ts
,
set the second duty cycle command based on
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
3. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is positive and the first duty cycle command is greater than both
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
and
(
Ts
-
(
Tdead
+
Tmin
)
/
2
Ts
,
set the second duty cycle command based on a 100 percent duty cycle,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
4. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is positive and the first duty cycle command is less than
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
,
but greater than
Tdead
T
s
,
set the second duty cycle command equal to the first duty cycle command,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
5. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is positive and the first duty cycle command is less than
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
and
Tdead
/
2
Ts
set the second duty cycle command based on a 0 percent duty cycle,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
6. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is positive and the first duty cycle command is less than
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
and
Tdead
Ts
but is greater than
Tdead
/
2
Ts
,
set the second duty cycle command based on
Tdead
T
s
,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
7. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is negative and the first duty cycle command is greater than
Ts
-
Tdead
Ts
,
but less than
Ts
-
(
Tdead
/
2
)
Ts
,
set the second duty cycle command based on
Ts
-
Tdead
Ts
,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
8. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is negative and the first duty cycle command is greater than both
Ts
-
Tdead
Ts
and
Ts
-
(
Tdead
/
2
)
Ts
,
set the second duty cycle command based on a 100 percent duty cycle,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
9. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is negative and the first duty cycle command is less than
Ts
-
Tdead
Ts
,
but greater than
Tdead
+
Tmin
Ts
,
set the second duty cycle command equal to the first duty cycle command,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
10. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is negative and the first duty cycle command is less than
Ts
-
Tdead
Ts
,
Tdead
+
Tmin
Ts
,
and
(
Tdead
+
Tmin
)
/
2
Ts
,
set the second duty cycle command based on a 0 percent duty cycle,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
11. The electric motor control system of claim 1 wherein the switching control module is configured to, when the current of the phase is negative and the first duty cycle command is less than
Ts
-
Tdead
Ts
and
Tdead
+
Tmin
Ts
,
but greater than
(
Tdead
+
Tmin
)
/
2
Ts
,
set the second duty cycle command based on
Tdead
+
Tmin
Ts
,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period.
12. The electric motor control system of claim 1 further comprising a current sensor configured to measure the current of the phase.
13. The electric motor control system of claim 1 wherein the predetermined deadtime period and the predetermined minimum period are less than the predetermined switching period.
14. The electric motor control system of claim 1 wherein the switching control module is further configured to:
based on the d-axis current command and the q-axis current command, determine a third duty cycle command for a second phase of the electric motor;
generate a fourth duty cycle command based on the third duty cycle command, the predetermined minimum period to transition second switches of the inverter module from OFF to ON, the predetermined switching period, the predetermined deadtime period, and whether a second current of the second phase is positive or negative,
wherein the second switches are connected between the energy storage device and the second phase of the electric motor; and
based on the fourth duty cycle command, control switching of the second switches the inverter module and control application of power from the energy storage device to the second phase of the electric motor.
15. The electric motor control system of claim 14 wherein the switching control module is further configured to:
based on the d-axis current command and the q-axis current command, determine a fifth duty cycle command for a third phase of the electric motor;
generate a sixth duty cycle command based on the fifth duty cycle command, the predetermined minimum period to transition third switches of the inverter module from OFF to ON, the predetermined switching period, the predetermined deadtime period, and whether a third current of the third phase is positive or negative,
wherein the third switches are connected between the energy storage device and the third phase of the electric motor; and
based on the sixth duty cycle command, control switching of the third switches the inverter module and control application of power from the energy storage device to the third phase of the electric motor.
16. An electric motor control method for a vehicle, comprising:
based on a motor torque request for an electric motor of the vehicle, generating a d-axis current command for the electric motor and a q-axis current command for the electric motor;
generating voltage commands based on the d-axis current command and the q-axis current command;
based on the d-axis current command and the q-axis current command, determining a first duty cycle command for a phase of the electric motor;
generating a second duty cycle command directly based on the first duty cycle command, a predetermined minimum period to transition switches of an inverter module from OFF to ON, a predetermined switching period, a predetermined deadtime period when both of the switches are OFF before one of the switches is turned ON, and whether a current of the phase is positive or negative,
wherein the switches are connected between an energy storage device and the phase of the electric motor; and
based on the second duty cycle command, controlling switching of the switches the inverter module and controlling application of power from the energy storage device to the phase of the electric motor.
17. The electric motor control method of claim 16 further comprising:
when the current of the phase is positive and the first duty cycle command is greater than
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
,
but less than
(
Ts
-
(
Tdead
+
Tmin
)
/
2
Ts
,
setting the second duty cycle command based on
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period; and
when the current of the phase is positive and the first duty cycle command is greater than both
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
and
(
Ts
-
(
Tdead
+
Tmin
)
/
2
)
Ts
,
setting the second duty cycle command based on a 100 percent duty cycle.
18. The electric motor control method of claim 16 further comprising:
when the current of the phase is positive and the first duty cycle command is less than
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
,
but greater than
Tdead
T
s
,
setting the second duty cycle command equal to the first duty cycle command,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period; and
when the current of the phase is positive and the first duty cycle command is less than
(
Ts
-
(
Tdead
+
Tmin
)
)
Ts
and
Tdead
/
2
Ts
,
setting the second duty cycle command based on a 0 percent duty cycle.
19. The electric motor control method of claim 16 further comprising:
when the current of the phase is positive and the first duty cycle command is less than
(
T
s
-
(
T
dead
+
T
min
)
)
T
s
and
Tdead
T
s
but is greater than
T
dead
/
2
T
s
,
setting the second duty cycle command based on
Tdead
Ts
,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period; and
when the current of the phase is negative and the first duty cycle command is greater than
T
s
-
T
dead
T
s
,
but less than
T
s
-
(
T
dead
/
2
)
T
s
,
setting the second duty cycle command based on
T
s
-
T
dead
T
s
.
20. The electric motor control method of claim 16 further comprising:
when the current of the phase is negative and the first duty cycle command is greater than both
T
s
-
T
dead
T
s
and
T
s
-
(
T
dead
/
2
)
T
s
,
setting the second duty cycle command based on a 100 percent duty cycle,
wherein Ts is the predetermined switching period, Tmin is the predetermined minimum period to transition the switches from OFF to ON, and Tdead is the predetermined deadtime period,
when the current of the phase is negative and the first duty cycle command is less than
T
s
-
T
dead
T
s
,
but greater than
T
dead
+
T
min
T
s
,
setting the second duty cycle command equal to the first duty cycle command;
when the current of the phase is negative and the first duty cycle command is less than
T
s
-
T
dead
T
s
,
T
dead
+
T
min
T
s
,
and
(
T
dead
+
T
min
)
/
2
T
s
,
setting the second duty cycle command based on a 0 percent duty cycle; and
when the current of the phase is negative and the first duty cycle command is less than
T
s
-
T
dead
T
s
and
T
dead
+
T
min
T
s
,
but greater than
(
T
dead
+
T
min
)
/
2
T
s
,
setting the second duty cycle command based on
T
dead
+
T
min
T
s
.