Motor control system and motor control method
First Claim
1. A motor control system comprising a motor having a resolver as a rotary sensor;
- an inverter for driving said motor; and
a control unit for controlling said inverter, said control unit executing phase calculation processing based on a phase signal which is an output of said resolver converted by an R/D converter;
calculating a voltage reference based on a current reference and a current value of said motor;
generating a PWM signal for controlling said inverter based on said voltage reference, whereina PWM synchronism signal in synchronism with said PWM signal is generated in said control unit, and said R/D converter is driven using said PWM synchronism signal.
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Abstract
An object of the present invention is to provide a motor control system comprising an R/D converter which is capable of outputting a good phase signal without being affected by the switching noise due to a PWM signal of an inverter and a motor control method.
A motor control system comprising a motor 3 having a resolver 8 as a rotary sensor; an inverter 10 for driving the motor; and a control unit 11 for controlling the inverter, the control unit executing phase calculation processing based on a phase signal which is an output of the resolver converted by an R/D converter 15, calculating a voltage reference based on a current reference and a current value of the motor detected by a current sensor 12, generating a PWM signal for controlling the inverter based on the voltage reference, wherein a PWM synchronism signal 212 in synchronism with the PWM signal is generated in the control unit, and the R/D converter 15 is driven using the PWM synchronism signal.
21 Citations
14 Claims
-
1. A motor control system comprising a motor having a resolver as a rotary sensor;
- an inverter for driving said motor; and
a control unit for controlling said inverter, said control unit executing phase calculation processing based on a phase signal which is an output of said resolver converted by an R/D converter;
calculating a voltage reference based on a current reference and a current value of said motor;
generating a PWM signal for controlling said inverter based on said voltage reference, whereina PWM synchronism signal in synchronism with said PWM signal is generated in said control unit, and said R/D converter is driven using said PWM synchronism signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
said division processing calculates tan θ and
cot θ
using a transfer function 1/(S+KA cos θ
) or 1/(S+KA sin θ
) which uses multiplication processing.
- an inverter for driving said motor; and
-
8. An electric vehicle control system according to claim 1, wherein said motor is a permanent magnet type motor.
-
9. A motor control method using a motor control system which comprises a motor having a resolver as a rotary sensor;
- an inverter for driving said motor; and
a control unit for controlling said inverter, the method comprising the steps of;executing phase calculation processing based on a phase θ
0 which is an output of said resolver converted by an R/D converter;
calculating a voltage reference based on a current reference and a current value of said motor;
generating a PWM signal for controlling said inverter based on said voltage reference;
generating a PWM synchronism signal in synchronism with said PWM signal in said control unit, and driving said R/D converter using said PWM synchronism signal;
converting the output of said resolver into a digital signal;
executing division processing to obtain tan θ
cot θ
from the converted digital signal; and
calculating a phase angle θ
0 to a rotating angle θ
of said resolver from the tan θ and
cot θ
through a function table.- View Dependent Claims (10, 11, 12)
said division processing calculates tan θ - and cot θ
using a transfer function 1/(S+KA cos θ
) or 1/(S+KA sin θ
) which uses multiplication processing.
-
11. A motor control method according to claim 10, wherein
said division processing comprises the steps of: -
acquiring outputs of said A/D converter KA sin θ
(n) and KA cos θ
(n);
in a case of calculating tan θ
, reading a value tan θ
in a preceding time, and setting TA=tan θ
(n−
1);
calculating |Δ
t|=KA sin θ
(n)−
TA×
KA cos θ
(n) to obtain a difference |Δ
t|;
comparing the difference |Δ
t| with a target value ε
, and setting tan θ
(n)=TA and completing the processing if |Δ
t| is smaller than ε
, and again obtaining said difference |Δ
t| by setting TA=TA+|Δ
t| if |Δ
t| is larger than ε
;
in a case of calculating cot θ
, reading a value cot θ
in a preceding step, and setting TA=cot θ
(n−
1);
calculating |Δ
c|=KA sin θ
(n)−
TA×
KA cos θ
(n) to obtain a difference |Δ
c|;
comparing the difference |Δ
c| with the target value ε
, and setting cot θ
(n)=TA and completing the processing if |Δ
c| is smaller than ε
, and again obtaining said difference |Δ
c| by setting TA=TA+|Δ
c| if |Δ
c| is larger than ε
; and
judging that said resolver is in an abnormal state when said differences |Δ
t|, |Δ
c| do not converge on the target value ε
even if the comparing steps are repeated several iterations within a control sampling time period.
-
-
12. A motor control method according to claim 10, wherein said division processing comprises the steps of:
-
calculating tan θ
by using KA sin θ
as an input and KA cos θ
as a multiplier of feedback value; and
calculating cot θ
by using KA cos θ
as an input and KA sin θ
as a multiplier of feedback value.
-
- an inverter for driving said motor; and
-
13. A motor control system comprising a motor having a resolver as a rotary sensor;
- an inverter for driving said motor; and
a control unit for controlling said inverter, whereinsaid control unit comprises a current reference generating unit for generating a d-axis current reference and a q-axis current reference;
a dq-axis current control unit for calculating AC voltage reference values Vu*, Vv*, Vw* by executing coordinate transformation of dq-axis voltage reference values Vd*, Vq* based on the dq-axis current references and a detected value of dq-axis current from motor current;
a PWM control unit for generating a PWM signal for driving said inverter based on said AC voltage reference values; and
an R/D converter composed of a phase calculating unit for calculating a phase signal used in the coordinate transformation processing, a speed calculating unit for calculating a speed based on said phase signal, an exciting signal generating unit of said resolver, an A/D converter for acquiring an output of said resolver as a detected signal and a θ
calculation processing unit, whereina PWM synchronism signal in synchronism with said PWM signal is generated in said control unit, and said R/D converter is driven using said PWM synchronism signal. - View Dependent Claims (14)
- an inverter for driving said motor; and
Specification