Sensorless brushless direct current (BLDC) motor position control

An electronic circuit for driving a load, the electronic circuit comprising:

• a gate driver for providing an associated control signal to each of one or more switching elements coupled to the electronic circuit and the load, the one or more switching elements controlling a voltage applied to the load;
• a controller to generate a speed signal based upon a received frequency demand signal and provide the speed signal to the gate driver;
• a zero crossing detector for detecting a zero crossing of a voltage applied to the load, the zero crossing detector configured to transition a zero crossing signal between a first logic level and a second logic level based on the detected zero crossing;
• a position estimator for estimating an angular position of the load, the position estimator comprising a counter configured to count in a first predetermined direction based on the first logic level of the zero crossing signal, and configured to count in a second predetermined direction based on the second logic level of the zero crossing signal;
• and
• an observer for determining a value of the counter after a predetermined elapsed time, the observer configured to generate an angular position signal based, at least in part, upon the determined value of the counter, the observer configured to generate a frequency signal based, at least in part, upon the determined value of the counter and provide the frequency signal to the controller and wherein the controller is configured to generate the speed signal based upon the received frequency demand signal and the frequency signal, wherein the observer is configured to receive at least on adjustment parameter, the observer configured to generate at least one of the angular position signal and the frequency signal based upon the determined value of the counter and the at least one adjustment parameter, and wherein the at least one adjustment parameter comprises a frequency adjustment parameter, KI and a position adjustment parameter, KP, and wherein the observer is configured to generate the frequency signal by multiplying the determined value of the counter by the frequency adjustment parameter, added to a previous value of the frequency signal, and wherein the observer is configured to generate the angular position signal by multiplying the determined value of the counter by the position adjustment parameter, added to a previous value of the angular position signal and added to the frequency signal.

A method for controlling operation of a brushless direct current (DC) motor having a plurality of windings, the method comprising:

• providing an associated control signal to each of one or more switching elements coupled to the electronic circuit, the one or more switching elements controlling a voltage applied to each of the plurality of windings of the motor;
• generating a speed signal based upon a received frequency demand signal;
• detecting a zero crossing of a voltage applied to at least one of the windings and transitioning a zero crossing signal between a first logic level and a second logic level based on the detected zero crossing;
• counting, by a counter, in a first predetermined direction based on the first logic level of the zero crossing signal, and in a second predetermined direction based on the second logic level of the zero crossing signal;
• determining a value of the counter after a predetermined elapsed time;
• and
• generating an angular position signal based, at least in part, upon the determined value of the counter;
• generating a frequency signal based, at least in part, upon the determined value of the counter and provide the frequency signal to the controller;
• generating the speed signal based upon the received frequency demand signal and the frequency signal
• receiving at least one adjustment parameter comprising a frequency adjustment parameter, KI, and a position adjustment parameter, KP;
• generating at least one of the angular position signal and the frequency signal based upon the determined value of the counter and the at least one adjustment parameter;
• generating the frequency signal by multiplying the determined value of the counter by the frequency adjustment parameter, added to a previous value of the frequency signal;
• and
• generating the angular position signal by multiplying the determined value of the counter by the position adjustment parameter, added to a previous value of the angular position signal and added to the frequency signal.

An electronic circuit for controlling operation of a brushless direct current (DC) motor having a plurality of windings, the electronic circuit comprising:

• a gate driver for providing an associated control signal to each of one or more switching elements coupled to the electronic circuit, the one or more switching elements controlling a voltage applied to each of the plurality of windings of the motor;
• a controller to generate a speed signal based upon a received frequency demand signal and provide the speed signal to the gate driver;
• a zero crossing detector for detecting a zero crossing of a voltage applied to at least one of the windings, the zero crossing detector configured to transition a zero crossing signal between a first logic level and a second logic level based on the detected zero crossing;
• a position estimator for estimating an angular position of the motor, the position estimator comprising a counter configured to count in a first predetermined direction based on the first logic level of the zero crossing signal, and configured to count in a second predetermined direction based on the second logic level of the zero crossing signal;
• and
• an observer for determining a value of the counter after a predetermined elapsed time, the observer configured to generate an angular position signal based, at least in part, upon the determined value of the counter, wherein the observer is configured to generate a frequency signal based, at least in part, upon the determined value of the counter and provide the frequency signal to the controller, wherein the controller is configured to generate the speed signal based upon the received frequency demand signal and the frequency signal, wherein the observer is configured to receive at least one adjustment parameter, the observer configured to generate at least one of the angular position signal and the frequency signal based upon the determined value of the counter and the at least one adjustment parameter, and wherein the at least one adjustment parameter comprises a frequency adjustment parameter, KI, wherein the at least one adjustment parameter is determined based on one or more characteristics of the motor.