Pulse amplitude modulated current converter

• US 7,719,864 B2
• Filed: 04/02/2008
• Issued: 05/18/2010
• Est. Priority Date: 04/02/2008
• Status: Expired due to Fees

• Current Assignee: Array Converter, Inc.
• Original Assignee: Array Converter, Inc.
• Inventors: Kernahan, Kent, Spanoche, Sorin Andrei
• Primary Examiner(s): NGUYEN, MATTHEW VAN
• Application Number:
  US12/061,025
• Publication Number:
  US 20090251936A1
• Time in Patent Office: 776 Days
• Field of Search: 363/65, 363/71, 332/108, 332/109, 332/115, 332/116, 323222-225, 323/268, 323/271
• US Class Current: 363/65
• CPC Class Codes: H02M 3/155 using semiconductor devices only
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load

Abstract

A direct current to pulse amplitude modulated (“PAM”) current converter, denominated a “PAMCC”, is connected to an individual source of direct current. The PAMCC receives direct current and provides pulse amplitude modulated current at its output. The pulses are produced at a high frequency relative to the signal modulated on a sequence of pulses. The signal modulated onto a sequence of pulses may represent portions of a lower frequency sine wave or other lower frequency waveform, including DC.

Claims

1. A pulse amplitude modulated current converter, wherein the pulse amplitude current converter is connected to a direct electrical current source, comprising:

a first and a second input terminal for receiving direct electrical current from the direct electrical current source, wherein one input terminal is connected to a positive electrical output terminal of the direct electrical current source and the other input terminal is connected to a negative electrical output terminal of the direct electrical current source;

a first coil connected in series with the first input terminal at a first terminal of the first coil;

a second coil connected in series with the second input terminal at a first terminal of the second coil;

a switch connected across a second terminal of the first coil and a second terminal of the second coil, wherein the switch includes a first terminal and a second terminal and a control gate;

a first SCR including a control gate and an anode terminal connected in parallel with the second terminal of the first coil and the first terminal of the switch;

a second SCR including a control gate and an anode terminal connected in parallel with the second terminal of the first coil and the first terminal of the switch;

a third SCR including a control gate and a cathode terminal connected in parallel with the second terminal of the second coil and the second terminal of the switch;

a fourth SCR including a control gate and a cathode terminal connected in parallel with the second terminal of the second coil and the second terminal of the switch;

a third coil connected between a first output terminal and a parallel connection comprising a cathode terminal of the first SCR, an anode terminal of the third SCR, and a first capacitor in series with a neutral terminal;

a fourth coil connected between a second output terminal and a parallel connection comprising a cathode terminal of the second SCR, an anode terminal of the fourth SCR, and a second capacitor in series with the neutral terminal; and

a controller, wherein the controller comprises;

an output terminal connected by a line to the control gate of the switch; and

four output terminals, each output terminal connected to a different SCR control gate by a line wherein the controller provides signals to control the switch and the first and the second and the third and the fourth SCR.

2. The pulse amplitude modulated current converter of claim 1, wherein the controller comprises a microprocessor.

3. A pulse amplitude modulated current converter, wherein the pulse amplitude current converter is connected to a direct electrical current source, comprising:

a first and a second input terminal for receiving direct electrical current from the direct electrical current source, wherein one input terminal is connected to a positive electrical output terminal of the direct electrical current source and the other input terminal is connected to a negative electrical output terminal of the direct electrical current source;

a first coil connected in series with the first input terminal at a first terminal of the first coil;

a second coil connected in series with the second input terminal at a first terminal of the second coil;

a first switch connected across the first terminal of the first coil and a second terminal of the second coil wherein the first switch includes a control gate;

a second switch connected across the first terminal of the second coil and a second terminal of the first coil wherein the second switch includes a control gate;

a first SCR including a control gate and an anode terminal connected to the second terminal of the first coil;

a second SCR including a control gate and an anode terminal connected to the second terminal of the first coil;

a third SCR including a control gate and a cathode terminal connected in parallel with the second terminal of the second coil;

a fourth SCR including a control gate and a cathode terminal connected in parallel with the second terminal of the second coil;

a third coil connected between a first output terminal and a parallel connection comprising a cathode terminal of the first SCR, an anode terminal of the third SCR, and a first capacitor in series with a neutral terminal;

a fourth coil connected between a second output terminal and a parallel connection comprising a cathode terminal of the second SCR, an anode terminal of the fourth SCR, and a second capacitor in series with the neutral terminal;

a controller, wherein the controller comprises;

an output terminal connected by a line to the control gate of the first switch;

an output terminal connected by a line to the control gate of the second switch; and

four output terminals, each output terminal connected by a line to a different SCR control gate wherein the controller provides signals to control the first and the second and the third and the fourth SCR.

4. The pulse amplitude modulated current converter of claim 3, wherein the controller comprises a microprocessor.

5. The pulse amplitude modulated current converter of claim 3, further comprising:

a third switch connected across the first and the second input terminals wherein the third switch includes a control gate;

a DPST relay across the third coil and the fourth coil wherein the relay is controlled by the controller to provide a connection between the third coil and the first output terminal and a connection between the fourth coil and the second output terminal, wherein the relay includes energizing connections;

an output terminal of the controller connected to the control gate of the third switch by a line, wherein the controller provides signals to the control gate of the third switch; and

an output terminal of the controller connected to the energizing connections of the relay, wherein the controller provides control signals to the energizing connections.