INVERTER CONTROL DEVICE, ELECTRIC COMPRESSOR USING INVERTER CONTROL DEVICE, AND ELECTRIC EQUIPMENT

• US 20130002178A1
• Filed: 06/27/2012
• Published: 01/03/2013
• Est. Priority Date: 06/29/2011
• Status: Abandoned Application

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: ENDOU, Katsumi, FUKUDA, Mitsuhiro, KODA, Atsushi
• Application Number:
  US13/534,928
• Publication Number:
  US 20130002178A1
• Time in Patent Office: Days
• US Class Current: 318/400.11
• CPC Class Codes: H02P 6/153 wherein the commutation is advanced from position signals phase in function of the speed
• CPC Class Codes: H02P 6/182 using back-emf in windings

Abstract

An inverter control device controls the operation of a brushless DC motor selsorlessly. A driving controller of the inverter control device switches commutation of switching elements from control based on a position detection commutation signal to control based on a forced synchronization commutation signal if an output voltage of an inverter circuit section is equal to or greater than a preset threshold and a value of a rotational speed detected by the rotational speed detector is equal to or less than a reference value less than a target value of the rotational speed. The output voltage controller of the inverter control device changes the output voltage control signal based on a phase difference detected by a phase difference detector when the driving controller is controlling commutation of switching elements based on the forced synchronization commutation signal.

Claims

1. An inverter control device comprising:

an inverter circuit section for driving a brushless DC motor which is a three-phase permanent magnet synchronous motor;

a rotor position signal generating circuit section which compares an induced voltage of the brushless DC motor to a reference voltage and generates a rotor position signal; and

an inverter control section which generates a control signal using the rotor position signal from the rotor position signal generating circuit section and outputs the control signal to the inverter circuit section;

wherein the inverter control section includes;

an output voltage controller which generates an output voltage control signal for controlling a three-phase voltage output from the inverter circuit section;

a rotor position detector for detecting a position of a rotor of the brushless DC motor based on the rotor position signal;

a phase difference detector for detecting a phase difference of a phase of the induced voltage with respect to a phase of the output voltage of the inverter circuit section, based on the rotor position signal from the rotor position signal generating circuit section;

a position detection commutation controller which generates a position detection commutation signal for commutating a plurality of switching elements included in the inverter circuit section, based on the detected rotor position signal from the rotor position detector;

a forced synchronization commutation controller which generates a forced synchronization commutation signal for forcibly commutating the plurality of switching elements, based on a target value of a rotational speed of the brushless DC motor, and the phase difference detected by the phase difference detector; and

a rotational speed detector for detecting a rotational speed of the brushless DC motor in operation;

a driving controller for controlling the output voltage of the inverter circuit section based on the output voltage control signal and controlling commutation of the plurality of switching elements based on the position detection commutation signal or the forced synchronization commutation signal; and

wherein the driving controller switches the commutation of the plurality of switching elements from control based on the position detection commutation signal to control based on the forced synchronization commutation signal, if the output voltage of the inverter circuit section is equal to or greater than a preset threshold and a detected value of the rotational speed which is detected by the rotational speed detector is equal to less than a reference value less than the target value of the rotational speed; and

the output voltage controller changes the output voltage control signal based on the phase difference detected by the phase difference detector, during a period when the driving controller is controlling the commutation of the plurality of switching elements based on the forced synchronization commutation signal.

2. The inverter control device according to claim 1,

wherein the output voltage controller changes the output voltage control signal to adjust the phase of the induced voltage to enable the rotor position detector to detect the position of the rotor, if the target value of the rotational speed becomes equal to or less than a preset lower limit value during a period when the driving controller is controlling the commutation of the plurality of switching elements based on the forced synchronization commutation signal;

and

the driving controller switches the commutation of the plurality of switching elements from the control based on the forced synchronization commutation signal to the control based on the position detection commutation signal, after the phase of induced voltage changes.

3. The inverter control device according to claim 1.

wherein the output voltage controller generates the output voltage control signal to decrease the three-phase voltage output from the inverter circuit section, if the phase difference of the induced voltage which is detected by the phase difference detector is a leading phase.

4. The inverter control device according to claim 1

wherein the output voltage controller generates the output voltage control signal to increase the three-phase voltage output from the inverter circuit section, if the phase difference of the induced voltage which is detected by the phase difference detector is a lagging phase.

5. The inverter control device according to claim 1,

wherein the output voltage controller generates the output voltage control signal to maintain the three-phase voltage output from the inverter circuit section, if the phase difference of the induced voltage which is detected by the phase difference detector is an intermediate phase.

6. An electric compressor comprising:

an inverter control device comprising an inverter circuit section for driving a brushless DC motor which is a three-phase permanent magnet synchronous motor;

a rotor position signal generating circuit section which compares an induced voltage of the brushless DC motor to a reference voltage and generates a rotor position signal; and

an inverter control section which generates a control signal using the rotor position signal from the rotor position signal generating circuit section and outputs the control signal to the inverter circuit section;

wherein the inverter control section includes;

an output voltage controller which generates an output voltage control signal for controlling a three-phase voltage output from the inverter circuit section;

a rotor position detector for detecting a position of a rotor of the brushless DC motor based on the rotor position signal;

a phase difference detector for detecting a phase difference of a phase of the induced voltage with respect to a phase of the output voltage of the inverter circuit section, based on the rotor position signal from the rotor position signal generating circuit section;

a position detection commutation controller which generates a position detection commutation signal for commutating a plurality of switching elements included in the inverter circuit section, based on the detected rotor position signal from the rotor position detector;

a forced synchronization commutation controller which generates a forced synchronization commutation signal for forcibly commutating the plurality of switching elements, based on a target value of a rotational speed of the brushless DC motor, and the phase difference detected by the phase difference detector;

a rotational speed detector for detecting a rotational speed of the brushless DC motor in operation; and

a driving controller for controlling the output voltage of the inverter circuit section based on the output voltage control signal and controlling commutation of the plurality of switching elements based on the position detection commutation signal or the forced synchronization commutation signal; and

wherein the driving controller switches the commutation of the plurality of switching elements from control based on the position detection commutation signal to control based on the forced synchronization commutation signal, if the output voltage of the inverter circuit section is equal to or greater than a preset threshold and a detected value of the rotational speed which is detected by the rotational speed detector is equal to less than a reference value less than the target value of the rotational speed; and

the output voltage controller changes the output voltage control signal based on the phase difference detected by the phase difference detector, during a period when the driving controller is controlling the commutation oldie plurality of switching elements based on the forced synchronization commutation signal;

the brushless DC motor controlled by the inverter control device; and

a compression mechanism for compressing a heat transmission medium.

7. Electric equipment comprising:

an inverter control device comprising an inverter circuit section for driving a brushless DC motor which is a three-phase permanent magnet synchronous motor;

a rotor position signal generating circuit section which compares an induced voltage of the brushless DC motor to a reference voltage and generates a rotor position signal; and

an inverter control section which generates a control signal using the rotor position signal from the rotor position signal generating circuit section and outputs the control signal to the inverter circuit section;

wherein the inverter control section includes;

an output voltage controller which generates an output voltage control signal for controlling a three-phase voltage output from the inverter circuit section;

a rotor position detector for detecting a position of a rotor of the brushless DC motor based on the rotor position signal;

a phase difference detector for detecting a phase difference of a phase of the induced voltage with respect to a phase of the output voltage of the inverter circuit section, based on the rotor position signal from the rotor position signal generating circuit section;

a position detection commutation controller which generates a position detection commutation signal for commutating a plurality of switching elements included in the inverter circuit section, based on the detected rotor position signal from the rotor position detector;

a forced synchronization commutation controller which generates a forced synchronization commutation signal for forcibly commutating the plurality of switching elements, based on a target value of a rotational speed of the brushless DC motor, and the phase difference detected by the phase difference detector;

a rotational speed detector for detecting a rotational speed of the brushless DC motor in operation; and

a driving controller for controlling the output voltage of the inverter circuit section based on the output voltage control signal and controlling commutation of the plurality of switching elements based on the position detection commutation signal or the forced synchronization commutation signal; and

wherein the driving controller switches the commutation of the plurality of switching elements from control based on the position detection commutation signal to control based on the forced synchronization commutation signal, if the output voltage of the inverter circuit section is equal to or greater than a preset threshold and a detected value of the rotational speed which is detected by the rotational speed detector is equal to less than a reference value less than the target value of the rotational speed; and

the output voltage controller changes the output voltage control signal based on the phase difference detected by the phase difference detector, during a period when the driving controller is controlling the commutation of the plurality of switching elements based on the forced synchronization commutation signal; and

the brushless DC motor controlled by the inverter control device.