# US 12,113,470 B2 · Method for coconstant torque control of EC motor in ventilation system

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- Number: US 12,113,470 B2
- Document ID: US12113470B2
- Status: Granted
- Kind: B2
- Application number: 18/083,449
- Filed: 2022-12-16
- Published: 2023-10-12
- Granted: 2024-10-08
- Earliest claimed: 2022-04-08
- Assignees: Zhongshan Broad-Ocean Motor Co., Ltd.
- Applicants: Zhongshan Broad-Ocean Motor Co., Ltd.
- Inventors: Wenqing Bian; Xiansheng Zhang; Jinren Guan
- Web page: https://patentgrep.com/patent/US12113470B2

## CPC

- H02P 6/08: Arrangements for controlling the speed or torque of a single motor (H02P6/10, H02P6/28 take precedence)
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS

## Abstract

A method for constant torque control of an EC motor of a ventilation system includes: defining a maximum speed spd_max_ref and a minimum speed spd_min_ref of an electronically commutated motor (ECM) within a constant-torque operation range; by using a proportional integral (PI) controller, calculating an upper reference torque T_ref_up with the maximum speed spd_max_ref as a first reference speed, and calculating a lower reference torque T_ref_low with the minimum speed spd_min_ref as a second reference speed; and T_ref_up>T_ref_low; receiving an externally input torque command Tcom; comparing the torque command Tcom, the upper reference torque T_ref_up, and the lower reference torque T_ref_low to determine a target torque Tact; and controlling the ECM to operate in a constant torque mode under the target torque Tact.

## Claims

### Claim 1

A method, comprising:
1) defining a maximum speed spd_max_ref and a minimum speed spd_min_ref of an electronically commutated motor (ECM) within a constant-torque operation range;
2) by using a proportional integral (PI) controller, calculating an upper reference torque T_ref_up with the maximum speed spd_max_ref as a first reference speed, and calculating a lower reference torque T_ref_low with the minimum speed spd_min_ref as a second reference speed; and T_ref_up>T_ref_low;
3) receiving an externally input torque command Tcom;
4) comparing the torque command Tcom, the upper reference torque T_ref_up, and the lower reference torque T_ref_low to determine a target torque Tact; and
5) controlling the ECM to operate in a constant torque mode under the target torque Tact.

### Claim 2 (depends on 1)

The method of claim 1, wherein in 4), if Tcom is greater than T_ref_up, let Tact=T_ref_up; if Tcom is less than T_ref_low, let Tact=T_ref_low; if Tcom falls between T_ref_up and T_ref_low, let Tact=Tcom.

### Claim 3 (depends on 2)

The method of claim 2, wherein in 2), by using the PI controller, an upper integral value interger_up is also acquired with the maximum speed spd_max_ref as the first reference speed, and a lower integral value interger_low with the minimum speed spd_min_ref as the second reference speed; in 4), if Tcom is greater than T_ref_up, let Tact=T_ref_up, and interger_up=Tact; if Tcom is less than T_ref_low, let Tact=T_ref_low, and interger_low=Tact; if Tcom falls between T_ref_up and T_ref_low, let Tact=Tcom, and interger_low=Tact, interger_up=Tact.

### Claim 4 (depends on 3)

The method of claim 3, wherein between 4) and 5), the method further comprises: calculating a maximum output torque Tmax based on a rotational speed SPD and a maximum output power of the EC motor; and comparing Tact with Tmax; if Tact is greater than Tmax, let Tact=Tmax.

### Claim 5 (depends on 4)

The method of claim 4, wherein the maximum output torque Tmax is calculated from the rotational speed SPD and the maximum output power P_out_max.

### Claim 6 (depends on 5)

The method of claim 5, wherein a dynamometer is used to ensure the EC motor operates at the maximum output power P_out_max, and the EC motor produces the maximum output torque Tmax through adjusting the rotational speed SPD.

### Claim 7 (depends on 2)

The method of claim 2, wherein between 4) and 5), the method further comprises: calculating a maximum output torque Tmax based on a rotational speed SPD and a maximum output power of the EC motor; and comparing Tact with Tmax; if Tact is greater than Tmax, let Tact=Tmax.

### Claim 8 (depends on 7)

The method of claim 7, wherein the maximum output torque Tmax is calculated from the rotational speed SPD and the maximum output power P_out_max.

### Claim 9 (depends on 8)

The method of claim 8, wherein a dynamometer is used to ensure the EC motor operates at the maximum output power P_out_max, and the EC motor produces the maximum output torque Tmax through adjusting the rotational speed SPD.

### Claim 10 (depends on 1)

The method of claim 1, wherein between 4) and 5), the method further comprises: calculating a maximum output torque Tmax based on a rotational speed SPD and a maximum output power of the EC motor; and comparing Tact with Tmax; if Tact is greater than Tmax, let Tact=Tmax.

### Claim 11 (depends on 10)

The method of claim 10, wherein the maximum output torque Tmax is calculated from the rotational speed SPD and the maximum output power P_out_max.

### Claim 12 (depends on 11)

The method of claim 11, wherein a dynamometer is used to ensure the EC motor operates at the maximum output power P_out_max, and the EC motor produces the maximum output torque Tmax through adjusting the rotational speed SPD.