EP0057083A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Power converter
Assignee: Oki Electric Industry Co Ltd
•
Filing: 1982-01-21
•
Granted: —
•
Expires: 2002-01-21
Abstract
Abstract A switching power converter comprises a DC power source (1), a switching element (2) and a transformer (3) interconnected so that the DC power source supplies power to the primary winding (3a) of the transformer (3) through the switching element. A rectifier (4, 5) and an output filter circuit (6, 7) are connected to the secondary winding (3b) of the transformer (3). A parallel circuit comprising a capacitor (12) and a coil (13) is inserted in the current path of the primary winding. A control circuit (14) controls the ON and/or OFF states of the switching element so that the switching element is turned to the ON state when the current in the coil (13) reaches a predetermined value which depends upon the output power of the power converter, and the switching element is turned to the OFF state after the current in the switching element reaches zero. Since the current in the switching element is zero when the switching element is turned to the OFF state, no power loss occurs in the OFF transition, and the conversion efficiency is thereby improved.
Inventors
- 👤 Yoshikazu Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 20:34
CPC Classifications
H; H02; H02M; H02M3/00; H02M3/22; H02M3/24; H02M3/28; H02M3/325; H02M3/335; H02M3/33538; H02M3/33546
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
193 words
1 . A power converter comprising a DC power source ( 1 ), a switching element (2), a transformer (3) having a secondary winding (3b) and a primary winding (3a) which is coupled to the DC power source and the switching element (2) so that the DC power source, the primary winding and the switching element form a closed circuit, a control circuit (14) for turning ON and OFF the switching element, a rectifier circuit coupled to the secondary winding of the transformer, and an output filter circuit coupled to the rectifier circuit, to the output of which filter circuit can be coupled an external load; characterised in that the power circuit further comprises a parallel circuit comprising a capacitor (12) and a coil ( 13 ) inserted in the closed circuit; and in that the control circuit (14) is operative such that the switching element (2) is turned to the ON state when the current in the coil (13) reaches a predetermined value which depends upon the output power of the power converter, and the switching element is turned to the OFF state after the current in the switching element reaches zero.
Claim 2
Dependent Claim
193 words
1 . A power converter comprising a DC power source ( 1 ), a switching element (2), a transformer (3) having a secondary winding (3b) and a primary winding (3a) which is coupled to the DC power source and the switching element (2) so that the DC power source, the primary winding and the switching element form a closed circuit, a control circuit (14) for turning ON and OFF the switching element, a rectifier circuit coupled to the secondary winding of the transformer, and an output filter circuit coupled to the rectifier circuit, to the output of which filter circuit can be coupled an external load; characterised in that the power circuit further comprises a parallel circuit comprising a capacitor (12) and a coil ( 13 ) inserted in the closed circuit; and in that the control circuit (14) is operative such that the switching element (2) is turned to the ON state when the current in the coil (13) reaches a predetermined value which depends upon the output power of the power converter, and the switching element is turned to the OFF state after the current in the switching element reaches zero.
Claim 3
Dependent Claim
102 words
2 . A power converter according to claim 1, charac- t e rised in that the control circuit (14) includes a first current transformer (15) and a resistor (17) connected thereto for monitoring the current in the coil (13); a first level detector (19) for detecting when the current in the coil (13) reaches the predetermined value which depends upon the output power; a second current transformer ( 1 6) and a resistor (18) connected thereto for monitoring the current in the switching element (2); and a second level detector (20) for detecting when the current in the switching element reaches zero.
Claim 4
Dependent Claim
62 words
A power converter according to claim 2, characterised in that a flip-flop circuit (23) is provided for turning ON and OFF the switching element (2); and in that the flip-flop (23) is turned to the ON state by the output of the first level detector (19) and is turned to the OFF state by the output of the second level detector (20).
Claim 5
Dependent Claim
31 words
A power converter according to claim 3, characterised in that a power amplifier (25) is provided between the output of the flip-flop (23) and the input of the switching element (2).
Claim 6
Dependent Claim
61 words
A power converter according to any preceding claim, characterised in that the rectifier circuit comprises two diodes (4, 5) one end of the first diode (4) being connected to one end of the secondary winding (3b), and the second diode (5) being connected to the other end of the first diode (4) and the other end of the secondary winding (3b).
Claim 7
Dependent Claim
24 words
A power converter according to any preceding claim, characterised in that the output filter circuit comprises a choke coil (6) and a capacitor (7).
Claim 8
Dependent Claim
33 words
A power converter according to any preceding claim, characterised by an error voltage amplifier (9) for adjusting the switching timing of the switching element (2) according to the power required by the load.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.