High Frequency Power Supply System with Closely Regulated Output for Heating a Workpiece

• US 20170179841A1
• Filed: 12/22/2016
• Published: 06/22/2017
• Est. Priority Date: 12/22/2015
• Status: Active Grant

• Current Assignee: The Thermatool Corporation (Inductotherm Group)
• Original Assignee: The Thermatool Corporation (Inductotherm Group)
• Inventors: IGNATOWSKI, Thomas G., FRAME, Lesley D., NALLEN, Michael A.
• Granted Patent: US 10,855,194 B2
• Time in Patent Office: Days
• CPC Class Codes: B23K 11/0873 of the longitudinal seam of tubes
• CPC Class Codes: B23K 11/241 Electric supplies B23K11/248 takes precedence
• CPC Class Codes: B23K 13/025 for tubes
• CPC Class Codes: B23K 13/08 Electric supply or control circuits therefor
• CPC Class Codes: B23K 2101/04 Tubular or hollow articles
• CPC Class Codes: H01F 29/10 having movable part of magnetic circuit high leakage transformers H01F38/08; dynamo-electric machines with movable part of magnetic circuit H02K23/44, H02K23/48
• CPC Class Codes: H02M 5/458 using semiconductor devices only
• CPC Class Codes: H02M 7/4818 with means for adaptation of resonance frequency, e.g. by modification of capacitance or inductance of resonance circuits
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A high frequency power supply system provides highly regulated power and frequency to a workpiece load where the highly regulated power and frequency can be independent of the workpiece load characteristics by inverter switching control and an inverter output impedance adjusting and frequency control network that can include precision variable reactors with a geometrically-shaped moveable insert core section and a stationary split-bus section with a complementary geometrically-shaped split bus section and split electric terminal bus section where the insert core section can be moved relative to the stationary split-bus section to vary the inductance of the variable reactors.

Claims

1. A high frequency power supply system having a closely regulated output for heating a workpiece load in a welding or annealing process, the high frequency power supply system comprising:

a full bridge or half-bridge inverter having a plurality of bridge switching devices and a single phase inverter output leads;

an inverter output impedance adjusting and frequency control network, having a control network input connected to the single phase inverter output leads and a control network output connected to the workpiece load; and

a microprocessor controller having one or more inverter control outputs to the plurality of bridge switching devices and one or more control network outputs to one or more variable impedance elements in the inverter output impedance adjusting and frequency control network for an adjustable power transfer from the single phase inverter output leads to the workpiece load and a variable output frequency from the single phase inverter output leads to the workpiece load independent of a workpiece impedance of the workpiece load.

2. A high frequency power supply system of claim 1 wherein the one or more variable impedance elements comprise:

a combination of a first pair of series variable reactors, a second pair of series variable reactors, a first pair of series variable capacitors, and a second pair of series variable capacitors arranged and connected in series to the single phase inverter output leads;

a combination of a pair of parallel variable reactors, a pair of parallel variable capacitors arranged and connected in parallel between the single phase inverter output leads; and

a parallel variable reactor arranged and connected in parallel between the single phase inverter output leads.

3. The high frequency power supply system of claim 1 wherein the system microprocessor controller provides hard switching control of the plurality of bridge switching devices from the one or more inverter control outputs in combination with an adjustable impedance control to the one or more variable impedance elements from the one or more control network outputs.

4. The high frequency power supply system of claim 1 wherein the system microprocessor controller provides pulse width modulated variable switching control of the plurality of bridge switching devices from the one or more inverter control outputs in combination with an adjustable impedance control to the one or more variable impedance elements from the one or more control network outputs.

5. The high frequency power supply system of claim 1 wherein the microprocessor controller provides a closed loop control to move a high frequency power supply system resonant point to a user selected output frequency inputted to the microprocessor controller and the microprocessor controller responsive to the user selected output frequency alternatively adjusts a microprocessor closed loop output to maintain a maximum output power transfer to the workpiece load or provide less than the maximum output power transfer as the high frequency power supply system moves off a resonance point.

6. The high frequency power supply system of claim 1 wherein the microprocessor controller provides an open loop output control for a high frequency power supply system resonant point to vary with the workpiece impedance of the workpiece load and alternatively adjusts a microprocessor output to maintain a maximum output power transfer or to maintain less than the maximum output power transfer as the high frequency power supply system moves off resonance.

7. The high frequency power supply system of claim 1 wherein the one or more variable impedance elements comprise at least one pair of variable reactors, at least one pair of variable reactors comprising:

a geometrically-shaped moveable insert core;

a stationary split-bus comprising;

a geometrically-shaped split bus section having a geometric complementary shape to the geometrically-shaped insert core to provide adjustable positions of insertion of the geometrically-shaped insert core into the geometrically-shaped split bus section to vary the inductance of the geometrically-shaped pair of reactors from a minimum inductance value when the geometrically-shaped insert core is fully inserted into the geometrically-shaped split bus section to a maximum inductance value when withdrawn from the geometrically-shaped split bus section to a position where the variable energy fields in a shaped interleaving space between the geometrically-shaped insert core and the geometrically-shaped split bus section are at a maximum value; and

a split electric bus terminal section for electrical connection of the geometrically-shaped pair of reactors in the load matching and frequency control apparatus; and

an actuator connected to the geometrically-shaped insert core for inserting and withdrawing the geometrically-shaped insert core into and from the geometrically-shaped split bus section.

8. The high frequency electrical heating system of claim 7 wherein the geometrically-shaped insert core is formed from a short-circuited electrically conductive material.

9. The high frequency electrical heating system of claim 8 wherein the short-circuited electrically conductive material alternatively comprises a copper sheet or a solid copper insert core.

10. The high frequency electrical heating system of claim 7 wherein the geometrically-shaped moveable insert core is alternatively formed from a solid or hollow magnetic material.

11. The high frequency electrical heating system of claim 10 wherein the solid or hollow magnetic material comprises a ferrite or a plurality of ferrites.

12. The high frequency electrical heating system of claim 7 wherein the geometrically-shaped moveable insert core and the geometrically-shaped split bus section are selected from the group of conic sections, wedge sections or parabolic conic sections.

13. The high frequency electrical heating system of claim 7 further comprising at least one fixed inductor in series combination with at least one of the variable reactor pairs.

14. The high frequency electrical heating system of claim 7 wherein the split electric bus terminal section of at least one of the pair of variable reactors are connected together to electrically form a single variable reactor.

15. The high frequency power supply system of claim 2 wherein at least one of the pair of variable capacitors comprises an adjustable interlayered plate elements of each one of the pair of variable capacitors.

16. The high frequency power supply system of claim 1 further comprising a human machine interface control panel having an integrated single user input control device to control power magnitude output and frequency output from the high frequency power supply system in combination with power and frequency display and heat affected zone size.

17. A method of controlling highly regulated power and frequency from a high frequency power supply system to a workpiece load in a welding or annealing process from a full bridge or half-bridge inverter having a plurality of switching devices via an inverter output impedance adjusting and frequency control network independent of a workpiece impedance of the workpiece load comprising the steps of:

providing at least one geometrically-shaped pair of variable reactors and at least one pair of variable capacitors in the inverter output impedance adjusting and frequency control network;

controlling a switching of the plurality of switching devices; and

controlling a variable impedance from the inverter output impedance adjusting and frequency control network to the workpiece load.

18. The method of claim 17 wherein controlling the switching of the plurality of switching devices comprises hard switching control of the plurality of bridge switching devices and controlling the variable impedance from the inverter output impedance adjusting and frequency control network to the workpiece load comprises adjusting the impedance of the at least one geometrically-shaped pair of variable reactors and the at least one pair of variable capacitors independent of the workpiece impedance of the workpiece load.

19. The method of claim 17 wherein controlling the switching of the plurality of switching devices comprises pulse width modulated variable switching control of the plurality of bridge switching devices and controlling the variable impedance from the inverter output impedance adjusting and frequency control network to the workpiece load comprises adjusting the impedance of the at least one geometrically-shaped pair of variable reactors and the at least one pair of variable capacitors independent of a workpiece impedance of the workpiece load.