Patent EP1133050A2 successfully refreshed from Google Patents.
EP1133050A2
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EP
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Method of estimating a rotor position of synchronous motor, method of controlling synchronous motor with no position sensor and a controller of synchronous motor
Assignee: Hitachi Ltd
•
Filing: 2000-09-04
•
Granted: —
•
Expires: 2020-09-04
Abstract
Abstract In a method of accurately estimating the rotor position of a synchronous motor having saliency from observable quantities, a control system for adjusting an output frequency ( ω 1) of an inverter (13) on the basis of a value of axis shift (Δ ) of the synchronous motor (2) to operate the motor (2) synchronously with the output frequency (ω1) is provided with an induced voltage estimating/axis shift operating unit (61). Currents (Idc, Iqc) resulting from conversion of detection currents (iu, iw) on a control axis, voltage commands (Vdc*, Vqc*) to be inputted to an inverse converter (44) and a speed command (ωr*) are inputted to the operating unit (61) to estimate an induced voltage of the motor 2 and determine the axis shift (Δ ) from a phase of the estimated induced voltage. By using an electrical constant Lq of inductance, a voltage drop across the inductance is determined by the product of a motor speed command (ωr*) and magnitude of motor current. The voltage drop is a virtual quantity that does not depend on the motor rotor position. A vector of the virtual quantity is so introduced as not to change a phase of the original induced voltage.
Inventors
- 👤 Kiyoshi Intellectual Property Group Sakamoto
- 👤 Tsunehiro Intellectual Property Group Endou
- 👤 Naohiko Intellectual Property Group Takahashi
- 👤 Haruo Intellectual Property Group Miura
- 👤 Hiroshi Intellectual Property Group Fujii
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 23:41
CPC Classifications
H; H02; H02P; H02P6/00; H02P6/14; H02P6/16; H02P6/18; H02P21/00; H02P21/14; H02P21/18; H02P2207/00; H02P2207/05
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
97 words
A method of estimating a rotor position of a
synchronous motor comprising the steps of: when estimating an induced voltage of the
synchronous motor (2) having saliency from a vector
difference between a motor applied voltage (V1) and
voltage drops (VL', Vr) due to resistance and
inductance of a motor winding, using a predetermined
value as said inductance to determine said voltage drop
(VL') due to inductance as a quantity dephased by a
predetermined amount from a motor current; and calculating the phase of the induced voltage
from the estimated induced voltage to estimate the
rotor position.
Claim 2
Dependent Claim
82 words
A synchronous motor rotor position estimating
method according to claim 1, wherein said voltage drop
due to inductance has a vector 90° leading said motor
current, an inductance (Lq) representing a motor
electrical constant of salient-pole machine is used as
said predetermined value, and said voltage drop due to
inductance is determined by the product of said
inductance (Lq), observable magnitude (Im) of said
motor current and observable frequency (ω1) of the
motor applied voltage or motor speed command value (ωr
*).
Claim 3
Dependent Claim
127 words
A synchronous motor rotor position estimating
method according to claim 1 or 2, wherein said motor
current is acquired in the form of observation values
of two axis components (Idc,Iqc) referenced to control
axes (dc-qc) of a rotary coordinate system, an
observation value of said motor applied voltage (V1), a
voltage drop determined by the product of an
observation value of said current and said resistance
and a voltage drop determined by the product of the
observation value of said current and said inductance
are computed in respect of axis components of said
control axis to calculate said vector difference in
terms of axis components, and the phase of said induced
voltage is determined by a ratio of the calculated
vector difference between the two axis components.
Claim 4
Dependent Claim
91 words
A synchronous motor rotor position estimating
method according to claim 1 or 2, wherein said motor
current is acquired as observable magnitude of motor
current, said motor applied voltage, said voltage drop
due to resistance and said voltage drop due to
inductance are computed in terms of components of the
current axis and components 90° leading said current
axis to calculate said vector difference in terms of
the components, and the phase of said induced voltage
is determined by a ratio of the calculated vector
difference between the two axis components.
Claim 5
Dependent Claim
108 words
A synchronous motor rotor position estimating
method comprising the steps of: when estimating an induced voltage of the
synchronous motor having saliency on the basis of the
fact that the induced voltage has a vector relation
resulting from subtraction of voltage drops due to
resistance and inductance of a motor winding from a
motor applied voltage, determining said voltage drop
due to inductance from a virtual voltage drop
representing a quantity 90° leading a motor current by
using a predetermined value as said inductance; and calculating a phase of the induced voltage
from an induced voltage estimated by using said virtual
voltage drop to estimate the rotor position.
Claim 6
Dependent Claim
65 words
A synchronous motor rotor position estimating
method according to claim 5, wherein the induced
voltage estimated by using said virtual voltage drop is
a virtual induced voltage having the same phase as that
obtained without using said virtual voltage drop and
being changeable in magnitude to maintain said vector
relation, and said phase of the virtual induced voltage
is calculated to estimate said rotor position.
Claim 7
Dependent Claim
106 words
A synchronous motor rotor position estimating
method comprising the steps of: when estimating an induced voltage of the
synchronous motor having saliency from a vector
difference between a motor applied voltage and voltage
drops due to resistance and inductance of a motor
winding, using a predetermined value as said inductance
and determining said voltage drop due to inductance as
the sum of a quantity dephased by a predetermined
amount from a motor current and a quantity generated by
changes in the magnitude and phase of the motor
current; and calculating a phase of the induced voltage
from an estimated induced voltage to estimate the rotor
position.
Claim 8
Dependent Claim
106 words
A synchronous motor rotor position estimating
method according to claim 7, wherein said voltage drop
due to inductance has a vector 90° leading said motor
current, inductances (Lq, Ld) representing motor
electrical constants of salient-pole machine are used
as said predetermined value, and said voltage drop due
to inductance is determined from the product of the
inductance (Lq), observable magnitude of said motor
current and observable frequency (ω1) of the motor
applied voltage or motor speed command value (ωr*),
the product of the inductance (Ld) and a quantity
generated by changes in observable magnitude and phase
of the motor current, and the sum of these products.
Claim 9
Independent Claim
198 words
A method of estimating a rotor position of a
synchronous motor having saliency and controlling the
synchronous motor without resort to position sensor,
comprising the steps of: when estimating an induced voltage of said
synchronous motor from a vector difference between a
motor applied voltage and voltage drops due to
resistance and inductance of a motor winding, using a
predetermined value as said inductance and determining
said voltage drop due to inductance as a quantity
leading a motor current by a predetermined phase; and determining a phase of an estimated induced
voltage and on the basis of the fact that this phase
indicates an axis shift angle between a virtual rotor
position from the control viewpoint and an unobservable
actual rotor position, decreasing a frequency of the
motor applied voltage to decrease the rotation speed of
the virtual rotor position when an axis shift angle
estimated from the phase of said induced voltage
indicates that the virtual rotor position leads the
actual rotor position in the rotation direction of the
rotor and increasing the frequency of the motor applied
voltage to increase the rotation speed of the virtual
rotor position when the estimated axis shift angle
indicates lagging.
Claim 10
Independent Claim
198 words
A method of estimating a rotor position of a
synchronous motor having saliency and controlling the
synchronous motor without resort to position sensor,
comprising the step of: when estimating an induced voltage of said
synchronous motor from a vector difference between a
motor applied voltage and voltage drops due to
resistance and inductance of a motor winding, using a
predetermined value as said inductance and determining
said voltage drop due to inductance as a quantity
leading a motor current by a predetermined phase; and determining a phase of an estimated induced
voltage and on the basis of the fact that the phase
indicates an axis shift angle between a virtual rotor
position from the control viewpoint and an unobservable
actual rotor position, increasing a torque command
value for the motor to increase the rotation speed of
the actual rotor position when the axis shift angle
estimated from the phase of said induced voltage
indicates that the virtual rotor position leads the
actual rotor position in the rotation direction of the
rotor and decreasing the torque command value for the
motor to decrease the rotation speed of the actual
rotor position when the estimated axis shift angle
indicates lagging.
Claim 11
Dependent Claim
42 words
A synchronous motor controlling method
without resort to position sensor according to claim 9
or 10, wherein said phase of induced voltage is
estimated by the synchronous motor rotor position
estimating method as recited in any one of claims 2 to
8.
Claim 12
Dependent Claim
69 words
A synchronous motor controlling method
without resort to position sensor according to claim 9,
10 or 11, wherein an error compensation value (Δ *)
of the axis shift angle indicated by said phase of
induced voltage is set and said frequency of motor
applied voltage or said torque command value is so
controlled as to minimize the difference between said
axis shift angle and said error compensation value.
Claim 13
Dependent Claim
45 words
A synchronous motor controlling method
without resort to position sensor according to claim
12, wherein setting of said error compensation value is
so adjusted as to minimize said motor current under a
condition that the rotation speed and the load on said
motor are constant.
Claim 14
Independent Claim
255 words
A system of controlling a synchronous motor
without resort to position sensor, comprising: an inverter (13) for converting a DC voltage
into a three-phase AC voltage of variable voltage and
variable frequency and applying the three-phase AC
voltage to the synchronous motor (2) having saliency; a current detector (32) for detecting a motor
current; a voltage command operating unit (42d, 42q,
43, 44; 53 to 55) for preparing voltage command values
(Vdc*, Vqc*) by using a virtual rotor position (dc)
in order that the magnitude and phase of detected
three-phase motor current follow command values of the
magnitude and phase of the motor current, respectively; a current command generating unit (50 to 52)
applied with a motor speed command value (ωr*) to
prepare said command values of the magnitude and phase
of motor current on the basis of the motor speed
command value (ωr*) and a motor speed estimation
value (ωr_det) ; an induced voltage estimating unit (61) for
estimating an induced voltage of said motor by using
the detected motor current, said voltage command value
and said motor speed command value (ωr * ) as well as
resistance and inductance of motor parameters,
estimating an axis shift angle (Δ ) indicative of a
shift between the virtual rotor position from the
control viewpoint and a real position and delivering
the axis shift angle; and a speed phase estimating unit (62) for
determining the motor speed estimation value (ωr_det)
and the virtual rotor position (dc) from the axis
shift angle (Δ ) and delivering them.
Claim 15
Independent Claim
272 words
A system of controlling a synchronous motor
without resort to position sensor, comprising: an inverter (13) for converting a DC voltage into a
three-phase AC voltage of variable voltage and variable
frequency and applying the three-phase AC voltage to
the synchronous motor (2); a current detector (32) for detecting a motor
current; a voltage command operating unit (42d, 42q,
43, 44; 53 to 55) for preparing voltage commands (Vdc
*, Vqc*) by using a virtual rotor position (dc) in
order that the magnitude and phase of detected three-phase
motor current follow command values of the
magnitude and phase of the motor current, respectively; a current command generating unit (50 to 52)
applied with a motor speed command value (ωr*) to
prepare said command values of the magnitude and phase
of motor current on the basis of the motor speed
command value (ωr *) and a motor speed estimation
value (ωr_det) ; an induced voltage estimating unit (61) for
estimating an induced voltage of said motor by using
the detected motor current, said voltage command values
and a frequency of motor applied voltage as well as
resistance and inductance of motor parameters,
estimating an axis shift angle (Δ ) indicative of a
shift between the virtual rotor position from the
control viewpoint and a real position and delivering
the axis shift angle; and a speed phase estimating unit (62) for
computing the frequency of motor applied voltage from
the axis shift angle (Δ ) to deliver it, and determining the motor speed estimation value (ωr_det)
and the virtual rotor position ( dc) from the computed
frequency of motor applied voltage to deliver them.
Claim 16
Dependent Claim
167 words
A synchronous motor controlling system
without resort to position sensor according to claim 14
or 15, wherein said induced voltage estimating unit
(61) includes operating means (611) for dividing said
induced voltage to calculate its dc axis and qc axis
components on a rotary coordinate system (dc-qc axis),
and operating means (621p) for calculating the axis
shift angle (Δ ) from a ratio between the dc axis and
qc axis components of the induced voltage, and said dc
axis component of the induced voltage is determined by
subtracting the product of said resistance and current
(Idc) and the product of said inductance and current
(Iqc) as well as said speed command value (ωr*) from
the d axis voltage command value, and said qc axis
component of the induced voltage is determined by
subtracting the product of said resistance and current
(Iqc) and the product of a predetermined value of said
inductance and current (Idc) well as said speed command
value from the q axis voltage command value.
Claim 17
Dependent Claim
78 words
A synchronous motor control system without
resort to position sensor according to any one of
claims 14, 15 and 16, further comprising an error
compensating unit (7) for applying an error
compensation value of said motor parameter to an
estimated value of axis shift angle (Δ ), wherein
said speed phase estimating unit (62) computes the
inputted axis shift angle (Δ) to cause it to follow
said error compensation value and delivers said motor
speed estimation value (ωr_det).
Claim 18
Independent Claim
122 words
A system of controlling a synchronous motor
having saliency without resort to position sensor,
comprising: induced voltage estimating means (61) for
estimating an induced voltage vector of the motor on a
virtual rotary coordinate system (rotary coordinate
system from the control viewpoint) having virtual flux
axis (dc axis) and qc axis leading the dc axis by 90°
in electrical angle and determining a phase angle of
the induced voltage vector relative to the qc axis; and speed control means (51) for using said
estimated phase angle as a shift quantity between the
qc axis and a real flux axis of the motor to control a
frequency of motor applied voltage or a torque command
value such that the shift quantity is decreased.
References Cited (Backward Citations)
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