Inverter with electrically controllable output

• US 5,083,255 A
• Filed: 07/05/1990
• Issued: 01/21/1992
• Est. Priority Date: 04/22/1983
• Status: Expired due to Term

• Current Assignee: Ole K Nilssen
• Original Assignee: Ole K Nilssen
• Inventors: Nilssen, Ole K.
• Primary Examiner(s): Skudy, R.
• Assistant Examiner(s): JONES, JUDSON
• Application Number:
  US07/548,197
• Time in Patent Office: 565 Days
• Field of Search: 323/242, 323/325, 323/326, 363/17, 363/18, 363/19, 363/22, 363/23, 363/34, 363/37, 363/38, 363/39, 363/98, 363/131, 363/132, 363/157, 363/159, 363/163, 363/164, 363/165
• US Class Current: 363/132
• CPC Class Codes: H02M 7/53832 in a push-pull arrangement
• CPC Class Codes: H05B 39/045 with high-frequency bridge converters H05B39/048 takes precedence
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

An inverter is powered by the pulsed DC voltage obtained by unfiltered full-wave rectification of the 60 Hz voltage from a regular electric utility power line. As long as the magnitude of the DC supply voltage is higher than a certain threshold level, the inverter can be triggered into 30 kHz self-sustaining oscillation. However, this oscillation stops as soon as the magnitude of the DC supply voltage falls below this certain threshold level. Thereafter, the inverter will not restart its oscillation, regardless of the magnitude of the DC supply voltage, except if provided with another trigger signal.

Thus, the inverter can be made to operate in fashion analogous to that of a thyristor: Once triggered, the inverter will provide a 30 kHz output of magnitude substantially proportional to that of its DC supply voltage; but as soon as the magnitude of its DC supply voltage decreases below a certain threshold level, as indeed occurs once every half-cycle of the 60 Hz voltage, it will cease to provide an output.

To provide a substantially continuous output of 30 kHz voltage, the inverter has to be triggered each half-cycle of the 60 Hz voltage, the trigger phasing being determinative of the RMS magnitude of the output voltage. If continuous triggering is not provided, no 30 kHz output voltage results.

Means are provided by which the triggering and its phasing are controlled electrically, thereby providing for an inverter with electrically controllable output voltage.

Claims

1. A power supply adapted to be powered from the relatively low frequency voltage on a regular electric power line and to provide a relatively high frequency output voltage, comprising:

rectifier means connected with said power line and operative to provide a DC supply voltage, said DC supply voltage being characterized by having an instantaneous unidirectional magnitude that is substantially equal to the instantaneous absolute magnitude of said low frequency voltage, whereby said instantaneous unidirectional magnitude increases above a certain threshold level once for each half-cycle of said relatively low frequency voltage and decreases below said certain threshold level once for each of said half-cycles;

inverter connected with said DC supply voltage and operative to provide said relatively high frequency output voltage, said inverter characterized by;

i) ceasing operation each time the instantaneous magnitude of said DC supply voltage decreases below said certain threshold level, ii) resuming operation each time after the magnitude of said DC supply voltage has increased above said certain threshold level, but only if provided with a trigger signal; and

electrically controllable trigger means operable to provide said trigger signal to said inverter some pre-selected time-period after each time the magnitude of said DC supply voltage has increased above said certain threshold level, the duration of said pre-selected time-period being less than that of said half-period;

whereby, as long as said trigger signals are being provided, said inverter starts and stops operation once during each of said half-cycles, thereby providing said high frequency output voltage for a pre-selected fraction of the duration of each of said half-cycles.

2. The power supply of claim 1 wherein said trigger means is operative by way of providing an adjustable voltage level to permit adjustment of the duration of said pre-selected time-period, resulting in a corresponding adjustment of said pre-selected fraction, thereby providing for electrically actuatable adjustment of the RMS magnitude of said output voltage, the RMS magnitude being referenced to the duration of said half-cycle.

3. The power supply of claim 1 wherein said trigger means is controllably operable to prevent said trigger signals from being provided during periods longer than the duration of said half cycle.

4. A power supply adapted to be powered from the relatively low frequency voltage on a regular electric power line and operative conditionally to provide a relatively high frequency output voltage, comprising:

rectifier means connected with said power line and operative to provide a non-filtered DC supply voltage;

conditionally oscillating inverter connected with said DC supply voltage and operative, when oscillating, to provide said output voltage, said inverter characterized by;

i) ceasing oscillation whenever the magnitude of said DC supply voltage decreases below a certain minimum level, and ii) resuming oscillation after the magnitude of said DC supply voltage has increased above said certain minimum level, but then only after having received a trigger pulse; and

trigger means conditionally operative to provide said trigger pulse a pre-selected brief time-period each time after the magnitude of said DC supply voltage has increased above said certain minimum level, said time-period being shorter than the period of said low frequency voltage;

whereby, as long as said trigger pulse is provided each time after the magnitude of said DC supply voltage has increased above said certain minimum level, said relatively high frequency output voltage is provided intermittently and periodically, with a periodicity not higher than that of said line voltage.

5. The power supply of claim 4 wherein said trigger means is operable selectively to provide or withhold said trigger pulses, thereby providing for electrically actuatable means for controlling the presence and/or non-presence of said high frequency output voltage.

6. An arrangement comprising:

connect means; and

frequency-converting power control means operative by way of the connect means to be connected with a relatively low frequency AC voltage having a period and operative during a fraction of said period to provide a relatively high frequency AC voltage to a load, the instantaneous absolute magnitude of this high frequency voltage, when provided, being substantially independent of the nature of the load and substantially proportional to the instantaneous absolute magnitude of the low frequency voltage,

the frequency-converting power control means comprising electrically actuatable control means operable to control the magnitude of said fraction, thereby to control the RMS magnitude of said high frequency voltage, said RMS magnitude being computed over at least a half-cycle of said low frequency voltage.

7. The power control means of claim 6 additionally comprising feedback means operative to maintain relatively constant the RMS magnitude of the high frequency voltage provided to the load even though the magnitude of the low frequency voltage may change.

8. A combination comprising:

a source providing an AC voltage at a pair of AC terminals;

the AC voltage having a period; and

frequency-converting power supply means connected with the AC terminals and operative to provide a high frequency voltage at an output;

the high frequency voltage having;

(i) a fundamental frequency that is substantially higher than that of the AC voltage;

(ii) during a first part the period, an RMS magnitude that varies in proportion to the absolute instantaneous magnitude of the AC voltage; and

(iii) during a second part of the period, an RMS magnitude that is substantially zero, and not propositional to the absolute magnitude of the power line voltage.

9. The combination of claim 8 wherein the frequency-converting power supply means includes control means operative to control the ratio between the first part and the second part.

10. A arrangement comprising:

a source operative to provide a power line voltage at a pair of power line terminals;

the power line voltage being of a relatively low frequency and having a basic cycle period;

the basic cycle period consisting of two half-cycle periods; and

conditioner means connected with the power line terminals and operative to provide a high-frequency output voltage at a pair of output terminals;

the frequency of the high-frequency output voltage being substantially higher than that of the power line voltage;

the magnitude of the high-frequency output voltage varying during each half-cycle period, being;

(i) substantially proportional to the absolute magnitude of the power line voltage during a first part of each half-cycle period; and

(ii) substantially zero, and not proportional to the absolute magnitude of the power line voltage, during a second part of each half-cycle period.

11. The power supply means of claim 10 including control means operative to permit control of the duration of said second part.

12. The power supply means of claim 10 wherein the sum of the duration of the first part and the duration of the second part equals the duration of the half-cycle period.

13. The power supply means of claim 10 combined with an incandescent lamp means connected with the output terminals.

14. A arrangement comprising:

a source operative to provide a power line voltage at a pair of power line terminals;

the power line voltage being of a relatively low frequency and having a fundamental period;

the fundamental period consisting of two half-cycles;

voltage conditioner means connected with the power line terminals and operative to provide a high-frequency output voltage at a pair of output terminals;

the frequency of the high-frequency output voltage being substantially higher than that of the power line voltage;

the peak-to-peak magnitude of the high-frequency output voltage varying during each half-cycle, being;

(i) substantially proportional to the absolute magnitude of the power line voltage during a first part of each half-cycle period; and

(ii) substantially zero during a second part of each half-cycle period; and

incandescent lamp means connected with the output terminals.