Direct-current power distribution in a control system

Patent metadata

Field	Value
Publication number	US-12237672-B2
Application number	US-202318543865-A
Country	US
Kind code	B2
Filing date	Dec 18, 2023
Priority date	Mar 4, 2019
Publication date	Feb 25, 2025
Grant date	Feb 25, 2025

Abstract

A control system may include a direct-current (DC) power bus for charging (e.g., trickle charging) internal energy storage elements in control devices of the control system. For example, the control devices may be motorized window treatments configured to adjust a position of a covering material to control the amount of daylight entering a space. The system may include a DC power supply that may generate a DC voltage on the DC power bus. For example, the DC power bus may extend from the DC power supply around the perimeter of a floor of the building and may be connected to all of the motorized window treatments on the floor (e.g., in a daisy-chain configuration). Wiring the DC power bus in such a manner may dramatically reduce the installation labor and wiring costs of an installation, as well as decreasing the chance of a miswire.

First claim

What is claimed is:

1. A load control system for controlling a plurality of electrical loads, the load control system comprising:
a plurality of load control devices configured to be coupled in parallel with each other across a DC power bus, wherein each load control device comprises:
an internal energy storage element configured to charge from a DC bus voltage;
an internal power supply configured to conduct current from the internal energy storage element and generate a supply voltage;
a load control circuit configured to receive the supply voltage and control power delivered to an electrical load; and
a control circuit configured to:
control the load control circuit for controlling the power delivered to the electrical load;
control when the internal energy storage element charges from the DC bus voltage;
send an indication of a storage level of the internal energy storage element;
receive an indication of a storage level of an internal energy storage element of a second load control device of the plurality of load control devices; and
determine to charge the internal energy storage element from the DC power bus based on a comparison between the storage level of the internal energy storage element and the received storage level of the internal energy storage element of the second load control device.

2. The load control system of claim 1 , wherein each of the plurality of load control devices is a motor drive unit for a motorized window treatment;
wherein the load control circuit of each of the plurality of load control devices comprises a motor drive circuit for a motor that is configured to control movement of a covering material of the motorized window treatment to control the amount of daylight entering a space; and
wherein the motor drive circuit is powered by the supply voltage.

3. The load control system of claim 2 , wherein each of the motor drive units are configured to determine whether to charge the respective internal energy storage element based on a respective storage level of the internal energy storage element and a storage level of an internal energy storage element of a second one of the motor drive units for a second motorized window treatment.

4. The load control system of claim 3 , wherein the motor drive unit is configured to charge its internal energy storage element in response to a determination that the storage level of its internal energy storage element is the smallest of all internal energy storage elements of the plurality of load control devices.

5. The load control system of claim 2 , wherein the motor drive unit is configured to receive an indication of a storage level of an internal energy storage element of each of the plurality of load control devices.

6. The load control system of claim 5 , wherein the motor drive unit is configured to determine, based on the indication of the storage level of the internal energy storage element of the load control device, that a second one of the motor drive units is charging the internal energy storage element of the second motor drive unit and, in response, supply power to the DC power bus from the internal energy storage element of the motor drive unit.

7. The load control system of claim 6 , wherein the motor drive unit is configured to render a controllable switching circuit of the motor drive unit conductive to allow the internal energy storage element to supply power to the DC power bus.

8. The load control system of claim 2 , further comprising:
a system controller configured to monitor a storage level of the internal energy storage element of each of the motor drive units and determine to charge the internal energy storage element of one of the motor drive units based on the storage level of the internal energy storage element of each of the motor drive units.

9. A load control device for controlling an electrical load in a load control system, the load control system having a plurality of load control devices for controlling a plurality of electrical loads, wherein the plurality of load control devices are configured to be coupled in parallel with each other across a DC power bus to receive a DC bus voltage, the load control device comprising:
an internal energy storage element configured to charge from the DC bus voltage;
an internal power supply configured to conduct current from the internal energy storage element and generate a supply voltage;
a load control circuit configured to receive the supply voltage and control power delivered to the electrical load; and
a control circuit configured to:
control the load control circuit for controlling the power delivered to the electrical load;
control when the internal energy storage element charges from the DC bus voltage;
send an indication of a storage level of the internal energy storage element;
receive an indication of a storage level of an energy storage element of another load control device; and
determine to charge the internal energy storage element from the DC power bus based on the storage level of the internal energy storage element and the received storage level of the energy storage element of the other load control device.

10. The load control device of claim 9 , wherein the load control device is a motor drive unit for a motorized window treatment;
wherein the load control circuit comprises a motor drive circuit for a motor that is configured to control movement of a covering material of the motorized window treatment to control the amount of daylight entering a space; and
wherein the motor drive circuit is powered by the supply voltage.

11. The load control device of claim 10 , wherein the control circuit is configured to charge the internal energy storage element in response to a determination that the storage level of the internal energy storage element is the smallest of all internal energy storage elements of the plurality of load control devices.

12. The load control device of claim 10 , wherein the control circuit is configured to receive a storage level of an internal energy storage element of each of the plurality of load control devices.

13. The load control device of claim 10 , further comprising:
a charging circuit configured to charge the internal energy storage element from the DC power bus to produce a storage voltage across the energy storage element.

14. The load control device of claim 13 , further comprising:
a controllable switching circuit coupled between the internal energy storage element and a connector, the connector configured to receive the DC bus voltage from the DC power bus; and
wherein the control circuit is configured to render the controllable switching circuit conductive to bypass the charging circuit and allow the internal energy storage element to supply power to the DC power bus to charge the internal energy storage element of the other load control device coupled to the DC power bus.

15. The load control device of claim 13 , further comprising:
a boost converter configured to increase the storage voltage across the energy storage element when connecting the energy storage element to the DC power bus to charge the internal energy storage element of the other load control device coupled to the DC power bus.

16. The load control device of claim 10 , wherein the control circuit is configured to determine that a different motor drive unit is charging its internal energy storage element and, in response, supply power to the DC power bus from the internal energy storage element of the motor drive unit.

17. The load control device of claim 13 , wherein the control cir

Assignees

• Lutron Tech Co Llc

Inventors

• Blair Edward J
• Bull John H
• Chambers Samuel F
• Dejonge Stuart W
• Parks Joseph R

Classifications

• H02J7/933

  the cycle being controlled or terminated in response to electric parameters · CPC title

• H02J7/40

  characterised by the exchange of charge or discharge related data · CPC title

• H02J7/865

  Battery or charger load switching, e.g. concurrent charging and load supply (H02J7/50 takes precedence) · CPC title

• H02J7/50

  acting upon multiple batteries simultaneously or sequentially · CPC title

• H02J7/342

  The other DC source being a battery actively interacting with the first one, i.e. battery to battery charging (with circuits for polarity protection H02J7/68) · CPC title