Method for calculating inertia moment and driver for electric motor

A mechanical inertia calculating method in a driver including a non-regenerative type power converter and executing velocity control of an electric motor with the use of a mechanical inertia constant, said driver being a converting apparatus for converting an AC voltage from an alternating power supply into an AC voltage of a variable voltage and a variable frequency, said non-regenerative type power converter including a forward converter for converting said AC voltage from said alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency,

• said mechanical inertia calculating method comprising:
• calculating mechanical inertia during only a motor acceleration time-period so that a voltage of said smoothing capacitor will not exceed a predetermined value;
• and
• when executing accelerations, executing one acceleration, and thereafter, bringing a velocity back to a velocity before said one acceleration, and thereafter, modifying a velocity-changing rate so as to execute a next acceleration.

A mechanical inertia calculating method in a driver including a non-regenerative type power converter and executing velocity control of an electric motor with use of a mechanical inertia constant, said driver being a converting apparatus for converting an AC voltage from an alternating power supply into an AC voltage of a variable voltage and a variable frequency, said non-regenerative type power converter including a forward converter for converting said AC voltage from said alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency,

• said mechanical inertia calculating method comprising:
• executing accelerations at a plurality of times at mutually different velocity-changing rates;
• and
• calculating mechanical inertia from integrated quantities of respective torque proportion signals and velocity-changing widths, and
• when executing said accelerations, executing one acceleration, and thereafter, bringing a velocity back to a velocity before said one acceleration, and thereafter, modifying said velocity-changing rate so as to execute a next acceleration.

A mechanical inertia calculating method in a driver including a non-regenerative type power converter and executing velocity control of an electric motor with use of a mechanical inertia constant, said driver being a converting apparatus for converting an AC voltage from an alternating power supply into an AC voltage of a variable voltage and a variable frequency, said non-regenerative type power converter including a forward converter for converting said AC voltage from said alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency,

• said mechanical inertia calculating method comprising:
• calculating mechanical inertia during only a motor acceleration time-period so that a voltage of said smoothing capacitor will not exceed a predetermined value,
• wherein, when executing accelerations, ω1 is equal to ω3 and ω2 is equal to ω4, where each reference notation denotes the following:
• ω1 a velocity at which integration of a torque proportion signal is started at one acceleration, ω2 a velocity at which said integration is terminated, ω3 a velocity at which said integration of said torque proportion signal is started at a next acceleration, and ω4 a velocity at which said integration is terminated.

A mechanical inertia calculating method in a driver including a non-regenerative type power converter and executing velocity control of an electric motor with use of a mechanical inertia constant, said driver being a converting apparatus for converting an AC voltage from an alternating power supply into an AC voltage of a variable voltage and a variable frequency, said non-regenerative type power converter including a forward converter for converting said AC voltage from said alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency,

• said mechanical inertia calculating method comprising:
• executing accelerations at a plurality of times at mutually different velocity-changing rates;
• and
• calculating mechanical inertia from integrated quantities of respective torque proportion signals and velocity-changing widths,
• wherein, when executing said accelerations, ω1 is equal to ω3 and ω2 is equal to ω4, where each reference notation denotes the following:
• ω1 a velocity at which integration of a torque proportion signal is started at one acceleration, ω2 a velocity at which said integration is terminated, ω3 a velocity at which said integration of said torque proportion signal is started at a next acceleration, and ω4 a velocity at which said integration is terminated.

An electric motor driver, comprising:

• a non-regenerative type power converter;
• and
• velocity controlling means for utilizing a mechanical inertia constant so as to execute velocity control of an electric motor, said electric motor driver being a converting apparatus for converting an AC voltage from an alternating power supply into an AC voltage of a variable voltage and a variable frequency, said non-regenerative type power converter including a forward converter for converting said AC voltage from said alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency,
• wherein there are provided accelerating means for executing accelerations at a plurality of times at mutually different velocity-changing rates, and inertia-identifying means for calculating mechanical inertia from integrated quantities of respective torque proportion signals and velocity-changing widths, and
• wherein, when executing said accelerations, there is provided means for setting a motor velocity at the time when integrations are terminated so that motor current will not become larger than a predetermined value.

An electric motor driver, comprising:

• a non-regenerative type power converter, and
• velocity controlling means for utilizing a mechanical inertia constant so as to execute velocity control of an electric motor, said electric motor driver being a converting apparatus for converting an AC voltage from an alternating power supply into an AC voltage of a variable voltage and a variable frequency, said non-regenerative type power converter including a forward converter for converting said AC voltage from said alternating power supply into a direct current DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency,
• wherein there are provided accelerating means for executing accelerations at a plurality of times at mutually different velocity-changing rates, and inertia-identifying means for calculating mechanical inertia from integrated quantities of respective torque proportion signals and velocity-changing widths, and
• wherein, when executing said accelerations, after one acceleration is executed, a velocity is brought back to a velocity before said one acceleration, and thereafter, said velocity-changing rate is modified so as to execute a next acceleration.

An electric motor driver, comprising:

• a non-regenerative type power converter;
• and
• velocity controlling means for utilizing a mechanical inertia constant so as to execute velocity control of an electric motor, said electric motor driver being a converting apparatus for converting an AC voltage from an alternating power supply into an AC voltage of a variable voltage and a variable frequency, said non-regenerative type power converter including a forward converter for converting said AC voltage from said alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency,
• wherein there are provided accelerating means for executing accelerations at a plurality of times at mutually different velocity-changing rates, and inertia-identifying means for calculating mechanical inertia from integrated quantities of respective torque proportion signals and velocity-changing widths, and
• wherein, when executing said accelerations, ω1 is equal to ω3 and ω2 is equal to ω4, where each reference notation denotes the following:
• ω1 a velocity at which integration of a torque proportion signal is started at one acceleration, ω2 a velocity at which said integration is terminated, ω3 a velocity at which said integration of said torque proportion signal is started at a next acceleration, and ω4 a velocity at which said integration is terminated.

A mechanical inertia calculating method in a driver including a power converter and executing velocity control of an electric motor with the use of a mechanical inertia constant, said power converter including a forward converter for converting an AC voltage from an alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency, said power converter converting said AC voltage from said alternating power supply into said AC voltage of a variable voltage and a variable frequency,

• said inertia calculating method comprising:
• when calculating a mechanical inertia from integrated quantities of torque proportion signals and velocity-changing widths at the time of changing a rotation velocity of said electric motor, executing accelerations at a plurality of times at mutually different velocity-changing rates;
• and
• calculating said mechanical inertia from said integrated quantities of said respective torque proportion signals and said velocity-changing widths,
• wherein, when executing said accelerations, a motor velocity at the time when integrations are terminated is set so that motor current will not become larger than a predetermined value.

A mechanical inertia calculating method in a driver including a power converter and executing velocity control of an electric motor with the use of a mechanical inertia constant, said power converter including a forward converter for converting an AC voltage from an alternating power supply into a direct current DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency, said power converter converting said AC voltage from said alternating power supply into said AC voltage of a variable voltage and a variable frequency,

• said inertia calculating method comprising:
• when calculating a mechanical inertia from integrated quantities of torque proportion signals and velocity-changing widths at the time of changing a rotation velocity of said electric motor, executing accelerations at a plurality of times at mutually different velocity-changing rates;
• calculating said mechanical inertia from said integrated quantities of said respective torque proportion signals and said velocity-changing widths, and
• when executing said accelerations, executing one acceleration, and thereafter, bringing a velocity back to a velocity before said one acceleration, and thereafter, modifying said velocity-changing rate so as to execute a next acceleration.

A mechanical inertia calculating method in a driver including a power converter and executing velocity control of an electric motor with the use of a mechanical inertia constant, said power converter including a forward converter for converting an AC voltage from an alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency, said power converter converting said AC voltage from said alternating power supply into said AC voltage of a variable voltage and a variable frequency,

• said inertia calculating method comprising:
• when calculating a mechanical inertia from integrated quantities of torque proportion signals and velocity-changing widths at the time of changing a rotation velocity of said electric motor, executing accelerations at a plurality of times at mutually different velocity-changing rates;
• and
• calculating said mechanical inertia from said integrated quantities of said respective torque proportion signals and said velocity-changing widths,
• wherein, when executing said accelerations, ω1 is equal to ω3 and ω2 is equal to ω4, where each reference notation denotes the following:
• ω1 a velocity at which integration of a torque proportion signal is started at one acceleration, ω2 a velocity at which said integration is terminated, ω3 a velocity at which said integration of said torque proportion signal is started at a next acceleration, and, ω4 a velocity at which said integration is terminated.

An electric motor driver, comprising:

• a power converter;
• and
• velocity controlling means for utilizing a mechanical inertia constant so as to execute velocity control of an electric motor, said power converter including a forward converter for converting an AC voltage from an alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency, said power converter converting said AC voltage from said alternating power supply into said AC voltage of a variable voltage and a variable frequency,
• wherein, when calculating a mechanical inertia from integrated quantities of torque proportion signals and velocity-changing widths at the time of changing a rotation velocity of said electric motor, there are provided accelerating means for executing accelerations at a plurality of times at mutually different velocity-changing rates, and inertia-calculating means for calculating said mechanical inertia from said integrated quantities of said respective torque proportion signals and said velocity-changing widths, and
• wherein, when executing said accelerations, there is provided means for setting a motor velocity at the time when integrations are terminated so that motor current will not become larger than a predetermined value.

An electric motor driver, comprising:

• a power converter;
• and
• velocity controlling means for utilizing a mechanical inertia constant so as to execute velocity control of an electric motor, said power converter including a forward converter for converting an AC voltage from an alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency, said power converter converting said AC voltage from said alternating power supply into said AC voltage of a variable voltage and a variable frequency,
• wherein, when calculating a mechanical inertia from integrated quantities of torque proportion signals and velocity-changing widths at the time of changing a rotation velocity of said electric motor, there are provided accelerating means for executing accelerations at a plurality of times at mutually different velocity-changing rates, and inertia-calculating means for calculating said mechanical inertia from said integrated quantities of said respective torque proportion signals and said velocity-changing widths, and
• wherein, when executing said accelerations, after one acceleration is executed, a velocity is brought back to a velocity before said one acceleration, and thereafter, said velocity-changing rate is modified so as to execute a next acceleration.

An electric motor driver, comprising:

• a power converter;
• and
• velocity controlling means for utilizing a mechanical inertia constant so as to execute velocity control of an electric motor, said power converter including a forward converter for converting an AC voltage from an alternating power supply into a DC voltage, a smoothing capacitor connected to a direct current circuit, and a backward converter for converting said DC voltage into said AC voltage of a variable voltage and a variable frequency, said power converter converting said AC voltage from said alternating power supply into said AC voltage of a variable voltage and a variable frequency,
• wherein, when calculating a mechanical inertia from integrated quantities of torque proportion signals and velocity-changing widths at the time of changing a rotation velocity of said electric motor, there are provided accelerating means for executing accelerations at a plurality of times at mutually different velocity-changing rates, and inertia-calculating means for calculating said mechanical inertia from said integrated quantities of said respective torque proportion signals and said velocity-changing widths, and
• wherein, when executing said accelerations, ω1 is equal to ω3 and ω2 is equal to ω4, where each reference notation denotes the following:
• ω1 a velocity at which an integration of said torque proportion signal is started at one acceleration, ω2 a velocity at which said integration is terminated, ω3 a velocity at which said integration of said torque proportion signal is started at a next acceleration, and ω4 a velocity at which said integration is terminated.