US3566243A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High frequency power supply
Assignee: Pillar Corp
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Filing: 1968-09-30
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Granted: 1971-02-23
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Expires: 1988-09-30
Abstract
Abstract A static, single-phase, alternating current supply for powering an inductive load. In a preferred embodiment, the load is an induction heating coil with parallel power factor correcting capacitors, but equivalent elements consisting of parallel connected inductance and capacitance may be incorporated in the system and any external load can then be powered. Adjustment of output power and/or voltage is accomplished by varying the frequency of the supply. The preferred embodiment includes an alternating current input of line voltage and frequency, a rectifier producing DC output voltage of substantially constant magnitude, an inverter capable of operation over a range of frequencies for converting the DC voltage to high frequency alternating current, and inductive reactance between the inverter and the load. The frequency of the inverter is controlled by an oscillator which has various inputs providing control functions.
Inventors
- 👤 James P Landis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:00
CPC Classifications
H; H02; H02M; H02M5/00; H02M5/40; H02M5/42; H02M5/44; H02M5/443; H02M5/45; H02M7/00; H02M7/42; H02M7/44; H02M7/48; H02M7/505; H02M7/515; H02M7/523; H02M7/5233; H02M7/5236; H05; H05B; H05B6/00; H05B6/02; H05B6/06
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
295 words
In a power supply, an inverter circuit comprising first and second DC voltage supply lines of opposite polarity, a capacitor voltage divider connected across said lines providing first and second voltage sources in series, a tank circuit connected to a point between said voltage sources and including inductance means and capacitance means in parallel with each other, a first conduction path connected between said first line and said tank circuit including a first semiconductor controlled rectifier connected to said first line, a first inductor connected to said rectifier, a first diode connected to said first inductor and a second inductor connected between said first diode and said tank circuit, a first capacitor connected across said first rectifier and said first inductor, a second diode connected between said second line and a point between said first diode and said second inductor, a second conduction path connected between said second line and said tank circuit, said second conduction path including a second semiconductor controlled rectifier connected to said second line, a third inductor connected to said second rectifier, a third diode connected to said third inductor, and a fourth inductor connected between said third diode and said tank circuit, said second rectifier and said third diode being pole oppositely to said first rectifier and first diode, a second capacitor connected across said second rectifier and said third inductor, a fourth diode connected between said first line and a point between said third diode and said fourth inductor, and means for supplying firing signals to said semiconductor controlled rectifiers for firing the same alternately, with said first and second capacitors discharging through the respective rectifier when fired and recharging oppositely to reverse bias the same for a predetermined time during which discharge takes place externally of the rectifier.
Claim 2
Dependent Claim
295 words
In a power supply, an inverter circuit comprising first and second DC voltage supply lines of opposite polarity, a capacitor voltage divider connected across said lines providing first and second voltage sources in series, a tank circuit connected to a point between said voltage sources and including inductance means and capacitance means in parallel with each other, a first conduction path connected between said first line and said tank circuit including a first semiconductor controlled rectifier connected to said first line, a first inductor connected to said rectifier, a first diode connected to said first inductor and a second inductor connected between said first diode and said tank circuit, a first capacitor connected across said first rectifier and said first inductor, a second diode connected between said second line and a point between said first diode and said second inductor, a second conduction path connected between said second line and said tank circuit, said second conduction path including a second semiconductor controlled rectifier connected to said second line, a third inductor connected to said second rectifier, a third diode connected to said third inductor, and a fourth inductor connected between said third diode and said tank circuit, said second rectifier and said third diode being pole oppositely to said first rectifier and first diode, a second capacitor connected across said second rectifier and said third inductor, a fourth diode connected between said first line and a point between said third diode and said fourth inductor, and means for supplying firing signals to said semiconductor controlled rectifiers for firing the same alternately, with said first and second capacitors discharging through the respective rectifier when fired and recharging oppositely to reverse bias the same for a predetermined time during which discharge takes place externally of the rectifier.
Claim 3
Dependent Claim
246 words
A static, single-phase, variable frequency power supply for converting low frequency alternating current from a source thereof to high frequency alternating current in a load including inductance and capacitance in parallel with each other, the load being either external or internal with respect to the power supply, said power supply including in combination, means for connection to said source to supply low frequency alternating current, rectifying means for converting said alternating current to direct current, inverter circuit means coupled to said rectifying means for converting said direct current to high frequency alternating current in said load, said inverter circuit means including controllable electron devices fired repetitively by control signals received from said load to produce said high frequency current, and an oscillator circuit coupled to said electron devices for supplying the control signals thereto, the frequency of said oscillator circuit being variable upon receipt of said control signals to control the frequency of said high frequency alternating current, said oscillator circuit including (b 1) a flip-flop circuit module integrated with said oscillator circuit having an output connected to at least one firing amplifier, (2) a voltage and power regulator circuit module having an output connected to said oscillator circuit, and (3) a lockout and limit circuit module interconnected between said oscillator circuit and said inverter circuit and between said oscillator circuit and said voltage and power regulator circuit to thereby control the firing of said electron devices in response to the power requirement of said load.
Claim 4
Dependent Claim
246 words
A static, single-phase, variable frequency power supply for converting low frequency alternating current from a source thereof to high frequency alternating current in a load including inductance and capacitance in parallel with each other, the load being either external or internal with respect to the power supply, said power supply including in combination, means for connection to said source to supply low frequency alternating current, rectifying means for converting said alternating current to direct current, inverter circuit means coupled to said rectifying means for converting said direct current to high frequency alternating current in said load, said inverter circuit means including controllable electron devices fired repetitively by control signals received from said load to produce said high frequency current, and an oscillator circuit coupled to said electron devices for supplying the control signals thereto, the frequency of said oscillator circuit being variable upon receipt of said control signals to control the frequency of said high frequency alternating current, said oscillator circuit including (b 1) a flip-flop circuit module integrated with said oscillator circuit having an output connected to at least one firing amplifier, (2) a voltage and power regulator circuit module having an output connected to said oscillator circuit, and (3) a lockout and limit circuit module interconnected between said oscillator circuit and said inverter circuit and between said oscillator circuit and said voltage and power regulator circuit to thereby control the firing of said electron devices in response to the power requirement of said load.
Claim 5
Dependent Claim
74 words
The power supply as claimed in claim 2, including further a first feedback means applying feedback signals to said oscillator circuit from the path of said high frequency alternating current, and power set point control means associated with said oscillator circuit for comparing the power level of the feedback signal with a set level to establish the frequency of the oscillator circuit at a value to produce a set power level in said load.
Claim 6
Dependent Claim
75 words
The power supply as claimed in claim 3, including a second feedback means applying second feedback signals to said oscillator circuit form the path of said high frequency alternating current, and voltage set point control means associated with said oscillator circuit for comparing the voltage level of said second feedback signals with a set level to establish the frequency of the oscillator circuit at a value to produce a set voltage level in said load.
Claim 7
Dependent Claim
96 words
The power supply as claimed in claim 1, in which said load exhibits peak power characteristics such that increasing frequency of said high frequency alternating current therein increases power up to a certain level beyond which power decreases, and in which said oscillator circuit includes limiting circuit means for comparing the phase angle of the control signals with that of the output of said inverter circuit means to limit the frequency of said oscillator circuit to a value to produce the peak power in said load even though the set power level has not been reached.
Claim 8
Dependent Claim
96 words
The power supply as claimed in claim 5, in which said electron devices of said inverter circuit means comprises a first semiconductor controlled rectifier, and said inverter circuit means further includes a first voltage source, inductance means and a first diode in series with said first semiconductor controlled rectifier and said load, capacitance means in parallel with said first semiconductor controlled rectifier and at least a portion of said inductance means and a second voltage source and a second diode in parallel with said first voltage source and said first diode and opposite in polarity thereto.
Claim 9
Dependent Claim
83 words
The power supply as claimed in claim 6, in which said inverter circuit means further includes a second semiconductor controlled rectifier, a second inductance means and a third diode in series with said second voltage source and said load, second capacitance means in parallel with said second semiconductor controlled rectifier and at least a portion of said second inductance means, and a fourth diode connecting said first voltage source to said last named series path and opposite in polarity to said third diode.
Claim 10
Dependent Claim
111 words
The power supply as claimed in claim 7, in which said oscillator means includes a unijunction transistor having an emitter and an output portion, a capacitor connected to said emitter, a current source connected to said emitter for charging said capacitor to a level at which it discharges through said emitter, and means responsive to said discharge to produce said control signals and supply the same to said semiconductor controlled rectifiers for firing the same alternately, said first and second capacitors discharging through said semiconduCtor controlled rectifies upon respective firing thereof and recharging reversely to produce reverse voltage thereon for a turnoff time before forward voltage is reapplied to said rectifiers.
Claim 11
Dependent Claim
44 words
The power supply as claimed in claim 8, in which said oscillator means includes lockout circuit means for monitoring the condition of the semiconductor controlled rectifiers to prevent firing thereof unless forward voltage exists on both of said rectifiers at the time for firing.
Claim 12
Dependent Claim
85 words
The power supply as claimed in claim 9, in which said lockout circuit means comprises impedance means connected to said unijunction transistor for blocking the output thereof, means for shorting said impedance means to prevent such blocking it forward blocking voltage exists on said rectifiers and comparison circuit means connected to said rectifiers and to said shorting means for comparing the operating potentials of the first and second controlled rectifiers to activate said shorting means only if blocking voltage exists on both of said rectifiers.
Claim 13
Dependent Claim
67 words
The power supply as claimed in claim 10, in which said limiting circuit means further includes a monitoring circuit connected to said semiconductor controlled rectifiers for monitoring the duration of reverse voltage thereon, and means responsive to said monitoring circuit for controlling said current source of said oscillator means to reduce the frequency thereof as the duration of said reverse voltage becomes shorter than a reference value.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |