Method of setting up an electrical motor speed control in a fluidic system

Patent metadata

Field	Value
Publication number	US-2023175515-A1
Application number	US-202217994479-A
Country	US
Kind code	A1
Filing date	Nov 28, 2022
Priority date	Dec 3, 2021
Publication date	Jun 8, 2023
Grant date	—

Abstract

A method of setting up an electrical motor speed control in a fluidic system including a turbomachine, an electric motor having a number p of pole pairs rotating the turbomachine, a variable speed drive controlling the speed of the electric motor, a sensor measuring a parameter H, Q of the turbomachine, and a system controller receiving the sensor's measurements and controlling the operation of the fluidic system. The method includes driving the electric motor at a predetermined electrical frequency, Fe, such that the turbomachine rotates with a controlled rotational speed N, determining the point of intersection of the system curve of the fluidic system and of the performance curve of the turbomachine to obtain the turbomachine's nominal operating point, and thus the nominal value, Hn, Qn, of the turbomachine parameter, measuring, with the sensor, the current value, H, Q of the turbomachine parameter, calculating the controlled rotational speed N by inputting, into the Affinity Laws, the determined nominal value, Hn, Qn, the measured current value, H, Q, and the known nominal rotational speed, Nn, of the turbomachine, determining the number p of pole pairs of the electric motor based on the ratio of the electrical frequency Fe and the calculated controlled rotational speed N, and adapting the setup of the variable speed drive to match the determined number p of pole pairs.

First claim

1 . A method of setting up an electrical motor speed control in a fluidic system, the fluidic system being characterised by a given system curve, the fluidic system comprising:
i. a turbomachine for transporting fluid through the fluidic system, the turbomachine being characterised by a given performance curve for a known nominal rotational speed, Nn, of the turbomachine's rotor; ii. an electric motor for rotating the turbomachine's rotor, the electric motor having a number p of pole pairs; iii. a variable speed drive for controlling the speed of the electric motor; iv. a sensor for measuring a parameter H, Q or P of the turbomachine, characterised by the turbomachine's performance curve; and v. a system controller for receiving the sensor's measurements and for controlling the operation of the fluidic system,
wherein the method:
a. driving the electric motor at a predetermined and constant electrical frequency, Fe, under the control of the variable speed drive, such that the turbomachine's rotor rotates with a controlled rotational speed N;
b. determining, by the system controller, the point of intersection of the system curve and the performance curve to obtain the nominal operating point of the turbomachine in the fluidic system at the nominal rotational speed Nn, and thus the nominal value, Hn, Qn, Pn, of the turbomachine parameter;
c. measuring, with the sensor, the current value, H, Q or P, of the turbomachine parameter;
d. calculating, by the system controller, the controlled rotational speed N based on the Affinity Laws applicable to turbomachines in combination with the determined nominal value, Hn, Qn or Pn, of the turbomachine parameter, the measured current value, H, Q or P, of the turbomachine parameter and the known nominal rotational speed, Nn, of the turbomachine's rotor;
e. determining, by the system controller, the number p of pole pairs of the electric motor based on the ratio of the electrical frequency Fe and the calculated controlled rotational speed N; and
f. adapting the setup of the variable speed drive to match the determined number p of pole pairs.

2 . A variable speed drive for the rotational speed control of an electric motor having a number p of pole pairs and driving a turbomachine installed in a fluidic system, the variable speed drive being configured to:
a. drive the electric motor at a predetermined and constant electrical frequency, Fe, such that the turbomachine rotates with a controlled rotational speed N; b. obtain the system curve of the fluidic system and the turbomachine's performance curve for a known nominal rotational speed, Nn; c. determine the point of intersection of the obtained system curve and the obtained performance curve to obtain the nominal operating point of the turbomachine in the fluidic system at the nominal rotational speed Nn, and thus the nominal value, Hn, Qn or Pn, of a parameter characterising the turbomachine's operation; d. obtain a current value, H, Q or P, of the turbomachine parameter while the turbomachine is rotating at the controlled rotational speed N; e. calculate the controlled rotational speed N based on the Affinity Laws applicable to turbomachines in combination with the determined nominal value, Hn, Qn or Pn, of the turbomachine parameter, the obtained current value, H, Q or P, of the turbomachine parameter and the known nominal rotational speed, Nn, of the turbomachine; f. determine the number p of pole pairs of the electric motor based on the ratio of the electrical frequency Fe and the calculated controlled rotational speed N; and g. adapt its setup to match the determined number p of pole pairs.

3 . The method of claim 1 , wherein the turbomachine parameter is the volumetric fluid flow rate Q generated by the turbomachine, or the total dynamic head H across the turbomachine, or the mechanical power P delivered by the turbomachine.

4 . The method of claim 1 , wherein the turbomachine is a pump, a compressor, or a fan, and in particular a centrifugal pump.

5 . The method of claim 1 , wherein the fluidic system is an HVAC system.

6 . The method of claim 1 , wherein the electric motor is a permanent magnet synchronous motor.

7 . The method of claim 1 , wherein the sensor is a pressure sensor, a flow rate sensor, or a power sensor.

8 . The variable speed drive of claim 2 , wherein the turbomachine parameter is the volumetric fluid flow rate Q generated by the turbomachine, or the total dynamic head H across the turbomachine, or the mechanical power P delivered by the turbomachine.

9 . The variable speed drive of claim 2 , wherein the turbomachine is a pump, a compressor, or a fan, and in particular a centrifugal pump.

10 . The variable speed drive of claim 2 , wherein the fluidic system is an HVAC system.

11 . The variable speed drive of claim 2 , wherein the electric motor is a permanent magnet synchronous motor.

12 . The variable speed drive of claim 2 , wherein the sensor is a pressure sensor, a flow rate sensor, or a power sensor.

Assignees

• Schneider Toshiba Inverter Europe Sas

Inventors

• Koteich Mohamad
• Ejjabraoui Kamal

Classifications

• F04D15/0066 Primary

  by changing the speed, e.g. of the driving engine · CPC title

• F05D2270/301

  Pressure · CPC title

• H02P1/04 Primary

  Means for controlling progress of starting sequence in dependence upon time or upon current, speed, or other motor parameter · CPC title

• H02P1/46

  for starting an individual synchronous motor {(H02P27/04 takes precedence)} · CPC title

• F04D15/0088

  Testing machines · CPC title