Hybrid direct current link system for a regenerative drive

Patent metadata

Field	Value
Publication number	US-10218262-B1
Application number	US-201715713829-A
Country	US
Kind code	B1
Filing date	Sep 25, 2017
Priority date	Sep 25, 2017
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

A system includes a converter operatively connected to an alternating current (AC) power source and a direct current (DC) bus, an inverter operatively connected to a motor and the DC bus, and a hybrid DC link system operatively connected between a high side and a low side of the DC bus. The converter includes a first plurality of switching devices in selective communication with each phase of the AC power source and the DC bus. The inverter includes a second plurality of switching devices in selective communication with each phase of the motor and the DC bus. The hybrid DC link system includes a ripple current control branch in parallel with an energy buffering branch.

First claim

What is claimed is:

1. A system, comprising:
a converter operatively connected to an alternating current (AC) power source and a direct current (DC) bus, the converter comprising a first plurality of switching devices in selective communication with each phase of the AC power source and the DC bus;
an inverter operatively connected to a motor and the DC bus, the inverter comprising a second plurality of switching devices in selective communication with each phase of the motor and the DC bus; and
a hybrid DC link system operatively connected between a high side and a low side of the DC bus, the hybrid DC link system comprising a ripple current control branch in parallel with an energy buffering branch, wherein:
the ripple current control branch comprises at least one film capacitor connected between the high side and the low side of the DC bus; and
the energy buffering branch comprises:
one or more electrolytic capacitors with an impedance element between the high side and the low side of the DC bus; and
a first resistor in parallel with a first electrolytic capacitor of the one or more electrolytic capacitors and a second resistor in series with the first resistor and parallel with a second electrolytic capacitor of the one or more electrolytic capacitors.

2. The system of claim 1 , wherein a resistance of the first resistor is substantially equal to the resistance of the second resistor, and a capacitance of the first electrolytic capacitor is substantially equal to the capacitance of the second electrolytic capacitor.

3. The system of claim 1 , wherein the impedance element comprises an inductor in series with a damping resistive element.

4. The system of claim 3 , wherein the damping resistive element comprises an external resistor.

5. The system of claim 3 , wherein the damping resistive element comprises a resistance integrated with the inductor.

6. The system of claim 3 , wherein the damping resistive element comprises a resistance integrated with at least one of the one or more electrolytic capacitors.

7. The system of claim 1 , further comprising a controller operable to transition the system to a fail-safe state based on one or more of: exceeding a maximum current rating in the hybrid DC link system and exceeding an imbalance limit in the hybrid DC link system.

8. A method comprising:
operably connecting a converter to an alternating current (AC) power source and a direct current (DC) bus, the converter comprising a first plurality of switching devices in selective communication with each phase of the AC power source and the DC bus;
operably connecting an inverter to a motor and the DC bus, the inverter comprising a second plurality of switching devices in selective communication with each phase of the motor and the DC bus;
operably connecting a hybrid DC link system between a high side and a low side of the DC bus, the hybrid DC link system comprising a ripple current control branch in parallel with an energy buffering branch, wherein:
the ripple current control branch comprises at least one film capacitor connected between the high side and the low side of the DC bus; and
the energy buffering branch comprises:
one or more electrolytic capacitors with an impedance element between the high side and the low side of the DC bus; and
a first resistor in parallel with a first electrolytic capacitor of the one or more electrolytic capacitors and a second resistor in series with the first resistor and parallel with a second electrolytic capacitor of the one or more electrolytic capacitors;

limiting a ripple current on the DC bus through the ripple current control branch of the hybrid DC link system; and
buffering variations in energy of the DC bus through the energy buffering branch of the hybrid DC link system.

9. The method of claim 8 , wherein a resistance of the first resistor is substantially equal to the resistance of the second resistor, and a capacitance of the first electrolytic capacitor is substantially equal to the capacitance of the second electrolytic capacitor.

10. The method of claim 8 , wherein the impedance element comprises an inductor in series with a damping resistive element.

11. The method of claim 10 , wherein the damping resistive element comprises an external resistor.

12. The method of claim 10 , wherein the damping resistive element comprises a resistance integrated with the inductor.

13. The method of claim 10 , wherein the damping resistive element comprises a resistance integrated with at least one of the one or more electrolytic capacitors.

14. The method of claim 8 , further comprising:
transitioning, by a controller, a regenerative drive system comprising the converter and the inverter to a fail-safe state based on one or more of: detecting, by the controller, an exceedance of a maximum current rating in the hybrid DC link system and detecting, by the controller, an exceedance of an imbalance limit in the hybrid DC link system.

Assignees

• Otis Elevator Co

Inventors

• Agirman Ismail

Classifications

• H02M5/40

  with intermediate conversion into DC · CPC title

• H02P27/085

  wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency · CPC title

• H02M7/12

  using discharge tubes with control electrode or semiconductor devices with control electrode · CPC title

• H02M1/4216 Primary

  operating from a three-phase input voltage (H02M1/4233 takes precedence) · CPC title

• B66B1/30 Primary

  effective on driving gear {, e.g. acting on power electronics, on inverter or rectifier controlled motor} · CPC title