Patent EP0584748A2 successfully refreshed from Google Patents.
EP0584748A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Control apparatus for an induction motor
Assignee: Sanyo Electric Co Ltd
•
Filing: 1993-08-20
•
Granted: —
•
Expires: 2013-08-20
Abstract
Abstract A control apparatus for an induction motor (1) includes a microcomputer (39) which evaluates an optimum number of rotations at which the operation efficiency of the motor becomes a maximum when the frequency (f₁) of an alternating current electric power applied to said induction motor is varied in accordance with a change of the load. An inverter circuit (40) is controlled by the microcomputer for adjusting the voltage outputted from the inverter circuit (40) such that the induction motor (1) rotates with the optimum number of rotations.
Inventors
- 👤 Norio Hayashi
- 👤 Takashi Ogawa
- 👤 Masaaki Takezawa
- 👤 Keishiro Igarashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 15:31
CPC Classifications
H; H02; H02P; H02P23/00; H02P23/08; H02P27/00; H02P27/04; F; F04; F04C; F04C18/00; F04C18/02; F04C18/0207; F04C18/0215; F04C18/30; F04C18/34; F04C18/356; F04C18/3562; F04C18/3564; F04C23/00; F04C23/001; F25; F25B; F25B49/00; F25B49/02; F25B49/025; F04C2240/00; F04C2240/40; F04C2240/403; F25B2600/00; F25B2600/02; F25B2600/021; Y; Y02; Y02B; Y02B30/00; Y02B30/70
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
75 words
A control apparatus for an induction motor (1) energized by an AC electric power having a variable frequency (f₁), comprising: evaluating means (39) for evaluating an optimum number of rotations of said induction motor in relation to said frequency (f₁); and voltage control means (40) for controlling the voltage of said alternating current electric power in a manner such that the number of rotations of said induction motor (1) becomes said optimum number of rotations.
Claim 2
Dependent Claim
32 words
A control apparatus according to claim 1, wherein said optimum number of rotations evaluating means includes arithmetic calculating means for calculating said optimum number of rotations on the basis of said frequency.
Claim 3
Dependent Claim
36 words
A control apparatus according to claim 1, wherein said optimum rotation number evaluating means includes storing means in which an optimum number of rotations is stored in advance for each of frequencies different from each other.
Claim 4
Dependent Claim
74 words
A control apparatus according to claim 1, wherein said alternating current electric power is generated by an inverter circuit of a PWM system, said inverter circuit including switching elements which are turned-on or off according to switching signals, and said voltage control means includes switching signal applying means for applying switching signals to said inverter circuit such that an alternating current electric power of a predetermined voltage can be outputted from said inverter circuit.
Claim 5
Dependent Claim
82 words
A control apparatus according to claim 4, wherein said switching signal applying means includes carrier wave generating means for generating a carrier wave, modulation wave generating means for generating a modulation wave, switching signal generating means for generating said switching signals by comparing a level of said carrier wave with a level of said modulation wave, and level adjusting means for adjusting a level of at least one of said carrier wave and said modulation wave in accordance with said predetermined voltage.
Claim 6
Dependent Claim
43 words
A control apparatus according to claim 5, wherein said carrier wave generating means includes counter means which is incremented or decremented in response to a clock signal, and said modulation wave generating means includes storage means for storing a modulation wave as data.
Claim 7
Dependent Claim
98 words
A control method for changing a capacity of a compressor in accordance with a change of a load for a refrigeration cycle which includes the compressor driven by an alternating current induction motor, comprising steps of; (a) changing a frequency of an alternating current electric power supplied to said induction motor in accordance with the change of said load; (b) evaluating an optimum rotation number of rotations of said induction motor according to said frequency; and (c) increasing or decreasing a voltage of said alternating current electric power such that said optimum number of rotations can be obtained.
Claim 8
Dependent Claim
26 words
A control method according to claim 7, wherein step (b) includes a step for calculating said optimum number of rotations on the basis of said frequencies.
Claim 9
Dependent Claim
43 words
A control method according to claim 7, wherein said step (b) includes (b-i) storing data of said optimum number of rotations for each of frequencies different from each other, and (b-ii) reading-out data of an optimum number of rotations corresponding to said frequency.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.