Self-balanced non-isolated hybrid modular DC-DC converter based on low duty cycle operation and sequential capacitors charging/discharging for medium voltage DC grids

• US 10,644,596 B2
• Filed: 12/01/2018
• Issued: 05/05/2020
• Est. Priority Date: 12/01/2017
• Status: Active Grant

• Current Assignee: Qatar University
• Original Assignee: Qatar University
• Inventors: Elserougi, Ahmed, Massoud, Ahmed, Ahmed, Shehab
• Primary Examiner(s): Mehari, Yemane
• Application Number:
  US16/207,121
• Publication Number:
  US 20190267898A1
• Time in Patent Office: 521 Days
• Field of Search: 323270-272
• CPC Class Codes: H02M 1/0003 Details of control, feedback or regulation circuits
• CPC Class Codes: H02M 1/0095 Hybrid converter topologies, e.g. NPC mixed with flying capacitor, thyristor converter mixed with MMC or charge pump mixed with buck
• CPC Class Codes: H02M 3/156 with automatic control of output voltage or current, e.g. switching regulators
• CPC Class Codes: H02M 3/157 with digital control
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: H02M 7/4835 comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage

Abstract

An electrical converter is provided, comprising a first half-bridge sub-module, a switch, and a first capacitor. The half-bridge sub-module is connected to the first capacitor, and the switch is connected to a terminal of the first half-bridge sub-module. The switch includes a plurality of insulated-gate bipolar transistors. The insulated-gate bipolar transistors are serially connected with each other.

Claims

1. An electrical converter, comprising:

a first half-bridge sub-module;

a switch; and

a first capacitor, wherein;

the half-bridge sub-module is connected to the first capacitor, and the switch is connected to a terminal of the first half-bridge sub-module,

the switch includes a plurality of insulated-gate bipolar transistors, and

the switch is configured to carry a sum of two currents during a first state, or a passive filter on a low voltage side is configured to provide a continuous current at the low voltage side.

2. The electrical converter of claim 1, wherein the insulated-gate bipolar transistors are serially connected with each other.

3. The electrical converter of claim 1, further comprising a plurality of cascaded half-bridge sub-modules.

4. The electrical converter of claim 3, wherein the cascaded half-bridge sub-modules are connected in series across the switch.

5. The electrical converter of claim 3, wherein at least one of the cascaded half-bridge sub-modules is coupled with a second capacitor.

6. The electrical converter of claim 1, wherein the switch is a high voltage switch.

7. The electrical converter of claim 1, wherein the first half-bridge sub-module is connected with the first capacitor via a resistor.

8. The electrical converter of claim 1, wherein the electrical converter is a DC-DC converter.

9. The electrical converter of claim 1, wherein the electrical converter is configured to be operated with a low duty cycle.

10. The electrical converter of claim 1, wherein the switch has a high-pulsed current rating.

11. The electrical converter of claim 10, wherein the switch current rating is based on the power flow from a LV side to a HV side.

12. The electrical converter of claim 1, wherein parallel modules for switches with high-pulsed current ratings are employed.

13. The electrical converter of claim 1, wherein an extracted duty cycle is provided to a sequential operation block to generate suitable gate pulses for the involved switches.

14. The electrical converter of claim 1, wherein the current of the HV side is measured and compared with a reference.

15. The electrical converter of claim 14, wherein the error signal is provided to a conventional proportional integral controller to generate the suitable duty cycle D.

16. The electrical converter of claim 1, wherein a second state of the operation has an input voltage of and an output voltage.

17. The electrical converter of claim 1, wherein the voltage of capacitor is controlled to be higher or lower than the voltage of a low voltage side.