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AssigneeHitachi, Ltd.
InventorsHironori Ohashi, Makoto Takase, Hiroyuki Tomita, Seiji Ishida
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A vector control apparatus having a DC braking function which is insusceptible to trip even upon DC braking and scarcely suffers vibration upon stoppage is provided. The control apparatus includes a DC braking control arithmetic unit 1 and switches S1, S3 and S4 controlled thereby, wherein in a vector control mode, the DC braking control arithmetic unit 1 sets all the switches S1, S3 and S4 to position a for realizing the vector control. When a DC control state is to be validated from the above-mentioned state, phase of voltage vector is calculated to change over the switches S1 and S3 to position b, and the absolute value of the q-axis current is compared with a reference value .alpha.. When the absolute value of the q-axis current is smaller than the reference value .alpha., the switch S4 is changed over to the position b to thereby effectuate only the d-axis current control. According to the present invention, there is provided a vector control apparatus having a tripless DC braking function. Since vibration occurring upon stoppage can be suppressed, stopping position accuracy upon DC braking in emergency can be enhanced. Further, low-noise systems are made available.
An induction motor control apparatus in which a current supplied to an induction motor through a power converter for converting to an AC power of a given frequency is controlled, being divided into vector components corresponding to magnetic flux and torque, respectively, wherein said induction motor control apparatus comprises means for fixing phase of a current command in response to a DC braking command, and means for fixing phase of a voltage command when an actual current of phase component orthogonal to the fixed phase of said current command becomes smaller than a predetermined value inclusive thereof.
An induction motor control apparatus in which a current supplied to an induction motor through a power converter for converting to an AC power of a given frequency is controlled, being divided into vector components corresponding to magnetic flux and torque, respectively, wherein said induction motor control apparatus comprises means for fixing phase of a current command in response to a DC braking command, and means for fixing phase of a voltage command when rotation speed of said induction motor becomes smaller than a predetermined value inclusive thereof during DC braking operation.
An induction motor control apparatus including a power converter, an induction motor connected to the output of said power converter, a d,q-converter for decomposing vectorially the current of said induction motor into a d-axis current for generating magnetic flux and a q-axis current for generating toque, a current command arithmetic unit for arithmetically determining from a torque command value d,q-axis current command values to be outputted, and a d,q-axis current control arithmetic unit for arithmetically determining d,q-axis voltages such that said d,q-axis currents are caused to follow said d,q-axis current command values, for thereby controlling rotation of said induction motor,
In an induction motor control in which an induction motor and a power converter are employed for controlling a current supplied to said induction motor through said power converter by dividing the current into vector components, a method of controlling said induction motor by fixing at first phase of a current command upon DC braking of said induction motor and then fixing phase of a voltage command when an actual current of the phase component orthogonal to the phase of said fixed current command becomes smaller than a predetermined value inclusive thereof.
In an induction motor control in which an induction motor and a power converter are employed for controlling a current supplied to said induction motor through said power converter by dividing the current into vector components, a method of controlling said induction motor by fixing at first phase of a current command upon DC braking of said induction motor and then fixing phase of a voltage command when rotation speed of said induction motor becomes smaller than a predetermined value inclusive thereof.
Dependencies are inferred from the claim text.