Demagnetization diagnosis device for motor and demagnetization diagnosis method for motor control device
A pulse voltage generator calculates a corrected pulse voltage application time. The pulse voltage generator also outputs, for the duration of the corrected pulse voltage application time, a voltage vector closest to a rotor phase from among twelve voltage vectors as a voltage vector command. A current detector detects three-phase output currents of a power converter, which are obtained when first to sixth switching elements of the power converter are turned on or off on the basis of the voltage vector command. A three-phase/two-phase converter converts the three-phase output currents to two-phase output currents to output d-axis current. When the d-axis current after the corrected pulse voltage application time has elapsed becomes less than or equal to a demagnetization determination threshold value, a demagnetization determiner determines that demagnetization occurs in a permanent magnet of a rotor of a motor.
1. A demagnetization diagnosis device for a motor, the demagnetization diagnosis device comprising:
a power converter including: a first switch element and a second switch element connected to each other in series between a first end and a second end of a capacitor; a third switch element and a fourth switch element connected to each other in series between the first end and the second end of the capacitor; and a fifth switch element and a sixth switch element connected to each other in series between the first end and the second end of the capacitor;
the motor including: a first winding connected to a connection point common between the first switch element and the second switch element; a second winding connected to a connection point common between the third switch element and the fourth switch element; and a third winding connected to a connection point common between the fifth switch element and the sixth switch element;
a pulse voltage generator that calculates a corrected pulse voltage application time period by a Mathematical Expression 5 below, and selects a voltage vector nearest to a rotor phase of a rotor of the motor out of voltage vectors V1 to V12 shown in a Table 1 below, and outputs the selected voltage vector as a voltage vector command, for the corrected pulse voltage application time period;
a current measurement circuit that measures output currents of three phases of the power converter outputted when the first to sixth switch elements of the power converter are turned ON or OFF in accordance with the Table 1 in response to the voltage vector command;
a three-phase/two-phase converter that converts the output currents of the three phases into output currents of two phases, and outputs a d-axis current; and
a demagnetization determiner that determines demagnetization as occurring in a permanent magnet of the rotor of the motor, in response to satisfaction of a condition that the d-axis current after passage of the corrected pulse voltage application time period is equal to or less than a demagnetization determination threshold
[Mathematical Expression 5]
T on′= T on/cos(Δθ) (5)
Ton: Before-correction pulse voltage application time period (fixed value)
Ton′: Corrected pulse voltage application time period
Δθ: Absolute value of difference between current rotor phase γ and phase of voltage vector command
TABLE 1
FIRST
SECOND
THIRD
SWITCH
SWITCH
SWITCH
ELEMENT
ELEMENT
ELEMENT
V1
ON
OFF
OFF
V2
ON
OFF
OFF
V3
ON
OFF
ON
V4
OFF
OFF
ON
V5
OFF
ON
ON
V6
OFF
ON
ON
V7
OFF
ON
ON
V8
OFF
ON
OFF
V9
OFF
ON
OFF
V10
OFF
OFF
OFF
V11
ON
OFF
OFF
V12
ON
OFF
OFF
FOURTH
FIFTH
SIXTH
SWITCH
SWITCH
SWITCH
ELEMENT
ELEMENT
ELEMENT
V1
ON
OFF
ON
V2
OFF
OFF
ON
V3
OFF
OFF
ON
V4
OFF
OFF
ON
V5
OFF
OFF
ON
V6
OFF
OFF
OFF
V7
OFF
ON
OFF
V8
OFF
ON
OFF
V9
ON
ON
OFF
V10
ON
ON
OFF
V11
ON
ON
OFF
V12
ON
OFF
OFF.
2. The demagnetization diagnosis device as claimed in claim 1 , wherein the pulse voltage generator further corrects the corrected pulse voltage application time period, by multiplying the corrected pulse voltage application time period by a first value, where the first value is obtained by dividing a direct-current voltage reference value by a direct-current voltage measured value.
3. The demagnetization diagnosis device as claimed in claim 1 , wherein the demagnetization determiner sets the demagnetization determination threshold, based on a temperature of a permanent magnet of the motor.
4. A demagnetization diagnosis device for a motor, the demagnetization diagnosis device comprising:
a power converter including: a first switch element and a second switch element connected to each other in series between a first end and a second end of a capacitor; a third switch element and a fourth switch element connected to each other in series between the first end and the second end of the capacitor; and a fifth switch element and a sixth switch element connected to each other in series between the first end and the second end of the capacitor;
the motor including: a first winding connected to a connection point common between the first switch element and the second switch element; a second winding connected to a connection point common between the third switch element and the fourth switch element; and a third winding connected to a connection point common between the fifth switch element and the sixth switch element;
a pulse voltage generator that calculates a corrected pulse voltage application time period by a Mathematical Expression 6 below, and selects a voltage vector nearest to a rotor phase of a rotor of the motor out of voltage vectors V1 to V12 shown in a Table 1 below, and outputs the selected voltage vector as a voltage vector command, for the corrected pulse voltage application time period;
a current measurement circuit that measures output currents of three phases of the power converter outputted when the first to sixth switch elements of the power converter are turned ON or OFF in accordance with the Table 1 in response to the voltage vector command;
a three-phase/two-phase converter that converts the output currents of the three phases into output currents of two phases, and outputs a d-axis current and a q-axis current; and
a demagnetization determiner that determines demagnetization as occurring in a permanent magnet of the rotor of the motor, in response to satisfaction of a condition that an alternating-current effective value calculated from the d-axis current and the q-axis current after passage of the corrected pulse voltage application time period is equal to or less than a demagnetization determination threshold
[
Mathematical
Expression
6
]
Ton
′
=
Ton
cos
2
(
Δ
θ
)
+
(
L
d
L
q
*
sin
(
Δθ
)
)
2
(
6
)
Ton: Pulse voltage application time period before correction (fixed value)
Ton′: Pulse voltage application time period after correction
Δθ: Absolute value of difference between current rotor phase γ and phase of voltage vector command
Ld: d-axis inductance
Lq: q-axis inductance
TABLE 1
FIRST
SECOND
THIRD
FOURTH
FIFTH
SIXTH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
V1
ON
OFF
OFF
ON
OFF
ON
V2
ON
OFF
OFF
OFF
OFF
ON
V3
ON
OFF
ON
OFF
OFF
ON
V4
OFF
OFF
ON
OFF
OFF
ON
V5
OFF
ON
ON
OFF
OFF
ON
V6
OFF
ON
ON
OFF
OFF
OFF
V7
OFF
ON
ON
OFF
ON
OFF
V8
OFF
ON
OFF
OFF
ON
OFF
V9
OFF
ON
OFF
ON
ON
OFF
V10
OFF
OFF
OFF
ON
ON
OFF
V11
ON
OFF
OFF
ON
ON
OFF
V12
ON
OFF
OFF
ON
OFF
OFF.
5. A demagnetization diagnosis device for a motor, the demagnetization diagnosis device comprising:
a power converter including: a first switch element and a second switch element connected to each other in series between a first end and a second end of a capacitor; a third switch element and a fourth switch element connected to each other in series between the first end and the second end of the capacitor; and a fifth switch element and a sixth switch element connected to each other in series between the first end and the second end of the capacitor;
the motor including: a first winding connected to a connection point common between the first switch element and the second switch element; a second winding connected to a connection point common between the third switch element and the fourth switch element; and a third winding connected to a connection point common between the fifth switch element and the sixth switch element;
a pulse voltage generator that calculates a corrected pulse voltage application time period by a Mathematical Expression 8 below, and selects a voltage vector nearest to a rotor phase of a rotor of the motor out of voltage vectors V1 to V12 shown in a Table 1 below, and outputs the selected voltage vector as a voltage vector command, for the corrected pulse voltage application time period;
a current measurement circuit that measures output currents of three phases of the power converter outputted when the first to sixth switch elements of the power converter are turned ON or OFF in accordance with the Table 1 in response to the voltage vector command;
a three-phase/two-phase converter that converts the output currents of the three phases into output currents of two phases, and outputs a d-axis current or both of the d-axis current and a q-axis current; and
a demagnetization determiner that determines demagnetization as occurring in a permanent magnet of the rotor of the motor, in response to satisfaction of a condition that the d-axis current or an alternating-current effective value calculated from the d-axis current and the q-axis current after passage of the corrected pulse voltage application time period is equal to or less than a demagnetization determination threshold
[Mathematical Expression 8]
T on″= T on*VDC/VDC′ (8)
Ton: Pulse voltage application time period before correction (fixed value)
Ton″: Pulse voltage application time period after correction
VDC: Direct-current voltage reference value (fixed value)
VDC′: Direct-current voltage measured value
TABLE 1
FIRST
SECOND
THIRD
FOURTH
FIFTH
SIXTH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
V1
ON
OFF
OFF
ON
OFF
ON
V2
ON
OFF
OFF
OFF
OFF
ON
V3
ON
OFF
ON
OFF
OFF
ON
V4
OFF
OFF
ON
OFF
OFF
ON
V5
OFF
ON
ON
OFF
OFF
ON
V6
OFF
ON
ON
OFF
OFF
OFF
V7
OFF
ON
ON
OFF
ON
OFF
V8
OFF
ON
OFF
OFF
ON
OFF
V9
OFF
ON
OFF
ON
ON
OFF
V10
OFF
OFF
OFF
ON
ON
OFF
V11
ON
OFF
OFF
ON
ON
OFF
V12
ON
OFF
OFF
ON
OFF
OFF.
6. A demagnetization diagnosis method for a motor control device, wherein the motor control device includes:
a power converter including: a first switch element and a second switch element connected to each other in series between a first end and a second end of a capacitor; a third switch element and a fourth switch element connected to each other in series between the first end and the second end of the capacitor; and a fifth switch element and a sixth switch element connected to each other in series between the first end and the second end of the capacitor; and
a motor including: a first winding connected to a connection point common between the first switch element and the second switch element; a second winding connected to a connection point common between the third switch element and the fourth switch element; and a third winding connected to a connection point common between the fifth switch element and the sixth switch element,
the demagnetization diagnosis method comprising:
with use of a pulse voltage generator, calculating a corrected pulse voltage application time period by a Mathematical Expression 5 below, and selecting a voltage vector nearest to a rotor phase of a rotor of the motor out of voltage vectors V1 to V12 shown in a Table 1 below, and outputting the selected voltage vector as a voltage vector command, for the corrected pulse voltage application time period;
with use of a current measurement circuit, measuring output currents of three phases of the power converter outputted when the first to sixth switch elements of the power converter are turned ON or OFF in accordance with the Table 1 in response to the voltage vector command; with use of a three-phase/two-phase converter, converting the output currents of the three phases into output currents of two phases, and outputting a d-axis current; and with use of a demagnetization determiner, determining demagnetization as occurring in a permanent magnet of the rotor of the motor, in response to satisfaction of a condition that the d-axis current after passage of the corrected pulse voltage application time period is equal to or less than a demagnetization determination threshold
[Mathematical Expression 5]
T on′= T on/cos(Δθ) (5)
Ton: Before-correction pulse voltage application time period (fixed value)
Ton′: Corrected pulse voltage application time period
Δθ: Absolute value of difference between current rotor phase Y and phase of voltage vector command
TABLE 1
FIRST
SECOND
THIRD
FOURTH
FIFTH
SIXTH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
V1
ON
OFF
OFF
ON
OFF
ON
V2
ON
OFF
OFF
OFF
OFF
ON
V3
ON
OFF
ON
OFF
OFF
ON
V4
OFF
OFF
ON
OFF
OFF
ON
V5
OFF
ON
ON
OFF
OFF
ON
V6
OFF
ON
ON
OFF
OFF
OFF
V 7
OFF
ON
ON
OFF
ON
OFF
V8
OFF
ON
OFF
OFF
ON
OFF
V9
OFF
ON
OFF
ON
ON
OFF
V10
OFF
OFF
OFF
ON
ON
OFF
V11
ON
OFF
OFF
ON
ON
OFF
V12
ON
OFF
OFF
ON
OFF
OFF.
7. A demagnetization diagnosis method for a motor control device, wherein the motor control device includes:
a power converter including: a first switch element and a second switch element connected to each other in series between a first end and a second end of a capacitor; a third switch element and a fourth switch element connected to each other in series between the first end and the second end of the capacitor; and a fifth switch element and a sixth switch element connected to each other in series between the first end and the second end of the capacitor; and
a motor including: a first winding connected to a connection point common between the first switch element and the second switch element; a second winding connected to a connection point common between the third switch element and the fourth switch element; and a third winding connected to a connection point common between the fifth switch element and the sixth switch element;
the demagnetization diagnosis method comprising:
with use of a pulse voltage generator, calculating a corrected pulse voltage application time period by a Mathematical Expression 6 below, and selecting a voltage vector nearest to a rotor phase of a rotor of the motor out of voltage vectors V1 to V12 shown in a Table 1 below, and outputting the selected voltage vector as a voltage vector command, for the corrected pulse voltage application time period;
with use of a current measurement circuit, measuring output currents of three phases of the power converter outputted when the first to sixth switch elements of the power converter are turned ON or OFF in accordance with the Table 1 in response to the voltage vector command; with use of a three-phase/two-phase converter, converting the output currents of the three phases into output currents of two phases, and outputting a d-axis current and a q-axis current; and with use of a demagnetization determiner, determining demagnetization as occurring in a permanent magnet of the rotor of the motor, in response to satisfaction of a condition that an alternating-current effective value calculated from the d-axis current and the q-axis current after passage of the corrected pulse voltage application time period is equal to or less than a demagnetization determination threshold
[
Mathematical
Expression
6
]
Ton
′
=
Ton
cos
2
(
Δ
θ
)
+
(
L
d
L
q
*
sin
(
Δθ
)
)
2
(
6
)
Ton: Pulse voltage application time period before correction (fixed value)
Ton′: Pulse voltage application time period after correction
Δθ: Absolute value of difference between current rotor phase γ and phase of voltage vector command
Ld: d-axis inductance
Lq q-axis inductance
TABLE 1
FIRST
SECOND
THIRD
FOURTH
FIFTH
SIXTH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
V1
ON
OFF
OFF
ON
OFF
ON
V2
ON
OFF
OFF
OFF
OFF
ON
V3
ON
OFF
ON
OFF
OFF
ON
V4
OFF
OFF
ON
OFF
OFF
ON
V5
OFF
ON
ON
OFF
OFF
ON
V6
OFF
ON
ON
OFF
OFF
OFF
V7
OFF
ON
ON
OFF
ON
OFF
V8
OFF
ON
OFF
OFF
ON
OFF
V9
OFF
ON
OFF
ON
ON
OFF
V10
OFF
OFF
OFF
ON
ON
OFF
V11
ON
OFF
OFF
ON
ON
OFF
V12
ON
OFF
OFF
ON
OFF
OFF.
8. A demagnetization diagnosis method for a motor control device, wherein the motor control device includes:
a power converter including: a first switch element and a second switch element connected to each other in series between a first end and a second end of a capacitor; a third switch element and a fourth switch element connected to each other in series between the first end and the second end of the capacitor; and a fifth switch element and a sixth switch element connected to each other in series between the first end and the second end of the capacitor; and
a motor including: a first winding connected to a connection point common between the first switch element and the second switch element; a second winding connected to a connection point common between the third switch element and the fourth switch element; and a third winding connected to a connection point common between the fifth switch element and the sixth switch element;
the demagnetization diagnosis method comprising:
with use of a pulse voltage generator, calculating a corrected pulse voltage application time period by a Mathematical Expression 8 below, and selecting a voltage vector nearest to a rotor phase of a rotor of the motor out of voltage vectors V1 to V12 shown in a Table 1 below, and outputting the selected voltage vector as a voltage vector command, for the corrected pulse voltage application time period;
with use of a current measurement circuit, measuring output currents of three phases of the power converter outputted when the first to sixth switch elements of the power converter are turned ON or OFF in accordance with the Table 1 in response to the voltage vector command;
with use of a three-phase/two-phase converter, converting the output currents of the three phases into output currents of two phases, and outputting a d-axis current or both of the d-axis current and a q-axis current; and
with use of a demagnetization determiner, determining demagnetization as occurring in a permanent magnet of the rotor of the motor, in response to satisfaction of a condition that the d-axis current or an alternating-current effective value calculated from the d-axis current and the q-axis current after passage of the corrected pulse voltage application time period is equal to or less than a demagnetization determination threshold
[Mathematical Expression 8]
T on″= T on*VDC/VDC′ (8)
Ton: Pulse voltage application time period before correction (fixed value)
Ton″: Pulse voltage application time period after correction
VDC: Direct-current voltage reference value (fixed value)
VDC′: Direct-current voltage measured value
TABLE 1
FIRST
SECOND
THIRD
FOURTH
FIFTH
SIXTH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
SWITCH
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
ELEMENT
V1
ON
OFF
OFF
ON
OFF
ON
V2
ON
OFF
OFF
OFF
OFF
ON
V3
ON
OFF
ON
OFF
OFF
ON
V4
OFF
OFF
ON
OFF
OFF
ON
V5
OFF
ON
ON
OFF
OFF
ON
V6
OFF
ON
ON
OFF
OFF
OFF
V7
OFF
ON
ON
OFF
ON
OFF
V8
OFF
ON
OFF
OFF
ON
OFF
V9
OFF
ON
OFF
ON
ON
OFF
V10
OFF
OFF
OFF
ON
ON
OFF
V11
ON
OFF
OFF
ON
ON
OFF
V12
ON
OFF
OFF
ON
OFF
OFF.