Rotor position sensing system for permanent magnet synchronous motors and related methods

Patent metadata

Field	Value
Publication number	US-11228265-B2
Application number	US-202016798729-A
Country	US
Kind code	B2
Filing date	Feb 24, 2020
Priority date	Dec 16, 2016
Publication date	Jan 18, 2022
Grant date	Jan 18, 2022

Abstract

Implementations of a system for sensing rotor position of a PMSM may include: a controller which may be coupled with the PMSM. The controller may be configured to apply a plurality of voltage vectors to the PMSM to generate a plurality of sensing signals from a stator of the PMSM in response. A comparator may be coupled to the PMSM configured to receive and to compare each one of the plurality of sensing signals with a threshold voltage. A rise time measurement circuit may calculate a plurality of rise times using the plurality of sensing signals in response to receiving a signal from the comparator. The rotor-angle estimation circuit may be configured to identify from the plurality of rise times a shortest rise time and a voltage vector corresponding with the shortest rise time and thereby identify the position of the rotor of the PMSM.

First claim

What is claimed is:

1. A system for sensing rotor position of a permanent magnet synchronous motor, comprising:
a controller configured to couple with a permanent magnet synchronous motor (PMSM), wherein the controller is configured to apply a plurality of voltage vectors to the PMSM to generate a plurality of sensing signals from a stator of the PMSM in response;
a rise time measurement circuit configured to couple to the PMSM, wherein the rise time measurement circuit is configured to calculate a plurality of rise times using the plurality of sensing signals;
a memory coupled with the rise time measurement circuit, wherein the memory is configured to store the plurality of rise times;
a rotor-angle estimation circuit coupled with the memory, wherein the rotor-angle estimation circuit is configured to calculate a rotor position relative to the stator of the PMSM using the plurality of rise times; and
a threshold voltage generator coupled to the controller, the threshold voltage generator configured to generate a threshold voltage in response to a command from the controller, wherein the threshold voltage is at least a first threshold voltage and a second threshold voltage.

2. The system of claim 1 , further comprising an amplifier coupled to a resistor, wherein the amplifier is configured to receive and to amplify the plurality of sensing signals to form a plurality of amplified sensing signals.

3. The system of claim 2 , further comprising a comparator coupled to the amplifier and to a threshold voltage generator, wherein the comparator is configured to receive and to compare each one of the plurality of amplified sensing signals with a threshold voltage generated by the threshold voltage generator.

4. The system of claim 2 , wherein the first threshold voltage and the second threshold voltage are calculated using a first threshold voltage equation and a second threshold voltage equation;
wherein the first threshold voltage equation is
V th1 =( G )( R sh )( I th1 )+ V off

and the second threshold voltage equation is
V th2 =( G )( R sh )( I th2 )+ V off
where V th1 is the first threshold voltage, V th2 is the second threshold voltage, G is a gain of the amplifier, R sh is a resistance from the resistor, I th1 is a first threshold current, I th2 is a second threshold current, and V off is the amplifier's offset voltage.

5. The system of claim 4 , wherein the first threshold current and the second threshold current are related by an equation I th1 = 4/3I th2 .

6. The system of claim 1 , wherein the plurality of voltage vectors is one of 12 and 24.

7. The system of claim 1 , further comprising an analog to digital (A/D) converter configured to couple to the PMSM, wherein the A/D converter is configured to convert the plurality of sensing signals into a plurality of digital current signals.

8. The system of claim 7 , wherein the controller is configured to generate a first A/D threshold value and a second A/D threshold value using one of a first A/D threshold value equation and a second A/D threshold value equation;
wherein the first A/D threshold value equation is

AD

th
⁢

⁢
1

=

V

th
⁢

⁢
1

⁡

(

2
n

Vref
AD

)

and the second A/D threshold value equation is

AD

th
⁢

⁢
2

=

V

th
⁢

⁢
2

⁡

(

2
n

Vref
AD

)

where AD th1 is the first A/D threshold value, AD th2 is the second A/D threshold value, V th1 is a first threshold voltage, V th2 is a second threshold voltage, n is the A/D resolution, and Vref AD is a full scale voltage value.

9. The system of claim 1 , wherein the rise time measurement circuit measures each rise time using a rise time measurement equation;
wherein the rise time measurement equation is

T
r

=

(

AD
th

-

AD
1

AD
2

-

AD
1

)

⁢

(

t
2

-

t
1

)

+

t
1

where T r is the rise time, AD th is one of the first A/D value threshold and the second A/D value threshold, AD 2 is a first value from the A/D converter formed when AD 2 exceeds AD th , AD 1 is a second value from the A/D converter formed prior to AD 1 exceeding AD th , t 2 is a time corresponding with AD 2 , and t 1 is a time corresponding with AD 1 .

10. The system of claim 1 , wherein the controller is configured to generate a first threshold current and a second threshold current, wherein the first threshold current and the second threshold current are related by the equation I th1 = 4/3I th2 where I th1 is the first threshold current and I th2 is the second th

Assignees

• Semiconductor Components Ind Llc

Inventors

• Okubayashi Masanori

Classifications

• H02P21/18 Primary

  Estimation of position or speed · CPC title

• H02P21/28

  Stator flux based control · CPC title

• H02P2203/03

  Determination of the rotor position, e.g. initial rotor position, during standstill or low speed operation · CPC title

• H02P6/186 Primary

  using difference of inductance or reluctance between the phases · CPC title

• H02P2203/01

  Motor rotor position determination based on the detected or calculated phase inductance, e.g. for a Switched Reluctance Motor · CPC title