US 7,583,039 B2 · Brushless DC motor control method and brushless DC motor controller

Abstract

The present invention discloses a control technology for brushless DC motor, in which firstly it is to build or import a motor running parameters' database, then detect the signals always running and the signals closely relevant to the rotor's rotating state such as the voltage and the current, and process these signals and figure out the signals about the rotor's position. Wherein these detected signals should be filtered before being used, and the best filter is the low-pass filter to cut out the high frequency components, and the cut-off frequency of the low-pass filter are determined by the motor running voltage U and PWM signal width when the motor is running at no load, finally determine if the motor is working properly by means of the motor running parameters stored in the database in advance, that is to determine if the detected value is identical with the one predicted from the database. Depending on the results from the detecting and comparison above, the control signal is generated to adjust the motor running state. With the technical method in this invention, the position sensor is not needed. This reduces the motor's external wiring amounts and the wiring complexity. Also the motor's seal is improved. Meanwhile, it is possible to measure the rotor's position accurately in any state according to this invention technology. Thus the motor running state can be controlled properly.

Claims35

Dependent claims

A sensorless DC motor controller for a sensorless brushless DC motor, comprising:

a position-detecting circuit, connecting to the motor, detecting a back-EMF zero crossing point-signal of a rotor of the motor and outputting a position-detecting signal, which is a back-EMF zero crossing position signal according to three-phase voltages of the motor;
a current-detecting circuit, connecting to the motor, detecting a line current and generating a current signal;
a power supply detecting circuit, connecting to an operating power source, detecting an operating voltage and supplying a voltage transform;
a central control circuit, connecting to the position-detecting circuit, current-detecting circuit, and power supply detecting circuit, generating control signals by means of the position-detecting signal, the current signal and a transformed voltage;
in which the central control circuit includes:
a storage device, storing a database of motor running parameters;
an Initialization device, initializing all devices in the controller;
a signal processing device, generating a central control output signal by means of received signals from the central control circuit and the database of the motor running parameters;
a power drive control circuit, connecting to the central control circuit, receiving control signals and generating high voltage electrical signals by means of the control signals;
a motor drive control circuit, connecting to the power drive control circuit and the motor, also connecting to an operating power supply, receiving the high voltage electrical signals and controlling motor running by means of these signals.

7 more elements

A sensorless DC motor controller for a sensorless brushless DC motor, comprising:

a position-detecting circuit, connecting to the motor, detecting a back-EMF zero crossing point signal of a rotor of the motor and outputting a position-detecting signal which is a back-EMF zero crossing position signal according to three-phase voltages;
a current-detecting circuit, connecting to the motor, detecting a line current and generating a current signal;
a voltage-detecting circuit, connecting to an operating power source, detecting an operating voltage and supplying a voltage transform;
a central control circuit, connecting to the position-detecting circuit, current-detecting circuit, and power supply detecting circuit, generating control signals by means of the position-detecting signal, the current signal and a transformed voltage;
in which the central control circuit is configured to,
store a database of motor running parameters;
initialize all devices in the controller;
generate a control circuit output signal by means of received signals from the central control circuit and the database of the motor running parameters;
a power drive control circuit, connecting to the central control circuit, receiving control signals and generating high voltage signals by means of the control signals;
a motor drive control circuit, connecting to the power drive control circuit and the motor, also connecting to an operating power supply, receiving the high voltage signals and controlling motor running by means of these signals.

7 more elements

A method of controlling a sensorless DC motor controller, comprising:

importing a database for motor running parameters and storing the database;
initializing all devices in the controller;
detecting a back-EMF zero crossing point signal of a rotor of a motor according to three-phase voltages and outputting a position-detecting signal, which is a back-EMF zero crossing position signal to calculate a real rotor position of the motor;
detecting a line current of the motor and generating a current signal;
generate control signals by means of the position-detecting signal, the current signal and a transformed voltage;
generating high voltage signals by means of the control signals;
controlling motor running by means of the high voltage signals.

4 more elements

Dependencies are inferred from the claim text.

Brushless DC motor control method and brushless DC motor controller

Life of this patent

Brushless DC motor control method and brushless DC motor controller

Life of this patent

Abstract

Claims35