EP0338798A2
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EP
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Pulse width modulation control unit of inverter
Assignee: Daikin Industries Ltd
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Filing: 1989-04-18
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Granted: —
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Expires: 2009-04-18
Abstract
Abstract A pulse width modulation (PWM) control unit of an inverter (3) in which a carrier frequency having a normal value of about 5KHz, calculates the ON time (PWM control pattern) at every calculation period corresponding to such carrier frequency and divides the calculated ON time into a plurality of pulses. This enables such conditions to be presented that simulate that the PWM control was carried out at high carrier frequency (20 KHz or higher), while using a one-chip microcomputer (8) which requires a comparatively long calculation time. Thus, PWM Control by high carrier frequency can be attained at lower cost and with a simple circuit construction.
Inventors
- 👤 Kazunobu C/O Shiga Plant Ohyama
- 👤 Hiroyuki C/O Shiga Plant Yamai
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 03:09
CPC Classifications
H; H02; H02M; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/53; H02M7/537; H02M7/5387; H02M7/53871; H02M7/53873; H02M7/53875; H02M7/53876
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
125 words
A pulse-width modulation control unit of an inverter provided with a bridge circuit which is connected to a three-phase winding and has a plurality of switching elements, whereby d.c. voltage is pulse-width modulated by ON/OFF motion of each switching element of said bridge circuit and three-phase alternating current voltage is applied to said three-phase winding, characterized in that it comprises an arithmetic operation means to calculate ON time of each switching element at a calculation period corresponding to carrier frequency; a dividing means to divide ON time of each switching element calculated by said arithmetic operation means; and a controlling means to ON control each switching element by a plurality of pulses obtained by dividing ON time into the plural number by said dividing means.
Claim 2
Dependent Claim
125 words
A pulse-width modulation control unit of an inverter provided with a bridge circuit which is connected to a three-phase winding and has a plurality of switching elements, whereby d.c. voltage is pulse-width modulated by ON/OFF motion of each switching element of said bridge circuit and three-phase alternating current voltage is applied to said three-phase winding, characterized in that it comprises an arithmetic operation means to calculate ON time of each switching element at a calculation period corresponding to carrier frequency; a dividing means to divide ON time of each switching element calculated by said arithmetic operation means; and a controlling means to ON control each switching element by a plurality of pulses obtained by dividing ON time into the plural number by said dividing means.
Claim 3
Dependent Claim
30 words
A pulse-width modulation control unit of an inverter according to Claim 1, wherein ON time of each switching element is equally divided into the fixed and preset number of pulses.
Claim 4
Dependent Claim
29 words
A pulse-width modulation control unit of an inverter according to Claim 1, wherein the dividing means divides ON time of each switching element into plural pulses of unequal width.
Claim 5
Dependent Claim
45 words
A pulse-width modulation control unit of an inverter according to Claim 3, wherein the dividing means divides ON time of each switching element into plural pulses of unequal width by linear interpolation so that the width of divided pulse changes in equal variation of width.
Claim 6
Dependent Claim
61 words
A pulse-width modulation control unit of an inverter according to Claim 3, wherein the dividing means divides ON time of each switching element into plural pulses of equal width and then divides said plural pulses of equal width into plural pulses of unequal width on the basis of the correction value table stored beforehand according to the phase of signal wave.
Claim 7
Dependent Claim
45 words
A pulse-width modulation control unit of an inverter according to Claim 1, wherein the dividing means divides ON time of each switching element into plural pulses of equal width or plural pulses of unequal width according to the rate of change of the ON time.
Claim 8
Dependent Claim
54 words
A pulse-width modulation control unit of an inverter according to Claim 6. wherein the dividing means divides ON time of each switching element into pulses of unequal width when the rate of change of ON time is large and into pulses of equal width when the rate of change of ON time is small.
Claim 9
Dependent Claim
64 words
A pulse-width modulation control unit of an inverter according to Claim 6, wherein The dividing means when dividing ON time of each switching element into puises of equal width divides it into the fixed and preset plural number and when dividing into pulses of unequal width divides it by linear interpolation so that the width of divided pulse changes in equal variation of width.
Claim 10
Dependent Claim
69 words
A pulse-width modulation control unit of an inverter according to Claim 6, wherein the dividing means when dividing ON time of each switching element into pulses of unequal width divides it first into plural pulses of equal width and then divides said plural pulses of equal width into pulses of unequal width on the basis of the correction value table stored beforehand according to the phase of signal wave.
Claim 11
Dependent Claim
185 words
A pulse-width modulation control unit of an inverter according to Claim 1, wherein the arithmetic operation means calculates ON time of each switching element at a calculation period corresponding to carrier frequency on the basis of the calculation formulae within the range of 0~π/3 of phase ϕ 0 τa - /T 0 =1-√2·(V 1 /Vd)·Sin(ϕ 0 + π/3) -rb-/To =1-√2·(V 1 /Vd)·Sinϕ 0 τc - /T 0 =1 or τa + /T 0 =1 τb - /T 0 =√2 (V 1 /Vd)·Sin(π/3-ϕ 0 ) τc-/T 0 =√2·(V 1 /Vd)·Sin (ϕ 0 + π/3) (τa - , τa + , τb, τc are respectively ON time of switching element of a phase, b phase and c phase on (+) side and (-) side, To = period, V 1 = effective voltage of fundamental wave, Vd = d.c. voltage to be applied) and specified the switching element which should take ON time calculated on the basis of the above calculation formulae within the range of π/3~2π of phase <po, on the basis of a permutation table of switching elements set beforehand according to phase ϕ 0 .
Claim 12
Dependent Claim
56 words
A pulse-width modulation control unit of an inverter according to Claim 10, wherein the arithmetic operation means has a ON time table which stored ON time of esch switching element within the range of 0~π/3 of phase ϕ 0 calculated beforehand on the basis of calculation formulae and obtains ON time from said ON time table.
Claim 13
Dependent Claim
38 words
A pulse-width modulation control unit of an inverter according to Claim 1, wherein the dividing means divides ON time of each switching element into plural pulses corresponding to the ripple based on current flowing through the three-phase winding.
Claim 14
Dependent Claim
39 words
A pulse-width modulation control unit of an inverter according to Claim 12, wherein the dividing means divides ON time of each switching element into plural pulses in the number corresponding to the rate of change of the ON time.
Claim 15
Dependent Claim
44 words
A pulse-width modulation control unit of an inverter according to Claim 13, wherein the dividing means makes plural pulses to be divided pulses of equal width or pulses of unequal width according to the rate of change of ON time of each switching element.
References Cited (Backward Citations)
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