Single-stage electronic ballast device

• US 20080018265A1
• Filed: 12/26/2006
• Published: 01/24/2008
• Est. Priority Date: 07/20/2006
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Lee, Ching-Ran, Chung, Hwei-Shung
• Granted Patent: US 7,545,102 B2
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H05B 41/2828 using control circuits for the switching elements H05B41/2827 takes precedence
• CPC Class Codes: H05B 41/2888 the bridge being commutated at low frequency, e.g. 1kHz
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A single-stage electronic ballast device outputs a square wave current to drive an HID lamp, which includes a rectifying and power factor correction unit, a bridge converter and a controller circuit. The rectifying and power factor correction unit has an input connected to an AC power source to rectify an AC power to a DC power. The bridge converter comprises two bridge arms formed by four switches, load terminals defined by midpoints of the two bridge arms and the HID lamp is connected between the load terminals. The bridge converter converts DC current to square wave current to drive the HID lamp with power control. The load terminals are selectively connected to output of the rectifying and power factor correction unit to adjust waveform of input current for higher power factor. The controller circuit has output connected to DC link voltage terminal and load terminal of the bridge converter.

Claims

1. A single-stage electronic ballast device outputting a square wave current to drive a HID lamp, comprising

a rectifying and power factor correction unit with an input connected to an AC power source to rectify an AC power to a DC power, the rectifying and power factor correction unit further providing input current path and energy storing unit;

a bridge converter comprising two bridge arms formed by four switches, load terminals defined by midpoints of the two bridge arms and an HID lamp connected between the load terminals, the bridge converter converting DC current to square wave current to drive the HID lamp with power control, the load terminals being selectively connected to output of the rectifying and power factor correction unit to adjust waveform of input current for higher power factor; and

a controller circuit with output connected to DC link voltage terminal and load terminal of the bridge converter and output connected to the four switches to drive the four switches with PWM control and protection, whereby the bridge converter outputs a square wave current.

2. The single-stage electronic ballast device as in claim 1, further comprising an output filter connected to the HID lamp to filter off harmonic current component in output current.

3. The single-stage electronic ballast device as in claim 1, further comprising an input filter connected between the rectifying and power factor correction unit and the AC power source to filter off harmonic current components in input current.

4. The single-stage electronic ballast device as in claim 1, wherein the bridge converter comprises first, second, third and fourth switching units to form arms of a full bridge, the connection node of the first switching unit and the fourth switching unit forming a first load terminal, the connection node of the second switching unit and the third switching unit forming a second load terminal, the connection node of the first switching unit and the second switching unit connected to a positive node (+) of a DC link capacitor, the connection node of the third switching unit and the fourth switching unit connected to a negative node (−

) of the DC link capacitor and being a common ground end.

5. The single-stage electronic ballast device as in claim 1, wherein the controller circuit comprises:

a DC bus connected to DC link voltage of the bridge converter;

a first sensor connected to the DC bus to sense the DC link voltage;

a first amplifier connected to the first sensor to amplify a feedback signal of the first sensor;

a second sensor connected to output terminal of the bridge converter to sense the output load current or output voltage of the bridge converter;

a second amplifier connected to the second sensor to amplify a feedback signal of the second sensor;

a reference voltage generator generating a reference voltage signal;

a square wave generator sending a signal to a logic circuit to determine the frequency of square wave current output by the bridge converter;

a first comparator connected to the first amplifier and the reference voltage generator to compare the output of the first amplifier and the output of the reference voltage generator;

a second comparator connected to the second amplifier and the reference voltage generator to compare the output of the second amplifier and the output of the reference voltage generator;

a logic circuit connected to the first comparator and the second comparator to generate a PWM signal according to output of the first comparator and the second comparator;

a driver with input connected to the logic circuit to amplify and isolate the PWM signal and then send to the bridge converter for driving the four switches to conduct pulse width modulation and protection.

6. A rectifying and power factor correction unit with input connected to an AC power source and output connected to a first load terminal and a second load terminal of a bridge converter, comprising:

a first rectifier comprising a first diode in serial connection with a fourth diode, a positive end of the first diode connected to a negative end of the fourth diode, a first power source terminal formed and connected to one end of the AC power and a negative end of the first diode forming a first output terminal;

a second rectifier comprising a second diode in serial connection with a third diode, a positive end of the second diode connected to a negative end of the third diode, a second power source terminal formed and connected to another end of the AC power, a negative end of the third diode forming a second output end, a positive end of the fourth diode and a positive end of the third diode connected to a common ground end; and

at least one energy storing inductor LPFC connected in series between the first power source terminal and the AC power source, or connected in series between the first output terminal and the second load terminal of the bridge converter, or connected in series between the second output terminal and the first load terminal of the bridge converter.

7. The rectifying and power factor correction unit as in claim 6, further comprising an input filter connected between the AC power source and first rectifier and the second rectifier.

8. The rectifying and power factor correction unit as in claim 7, wherein the input filter is connected in series with the energy storing inductor L_PFC and the first power source terminal.

9. The rectifying and power factor correction unit as in claim 6, wherein the bridge converter comprises first, second, third and fourth switching units to form arms of a full bridge, the connection node of the first switching unit and the fourth switching unit forming a first load terminal, the connection node of the second switching unit and the third switching unit forming a second load terminal, the connection node of the first switching unit and the second switching unit connected to a positive node (+) of a DC link capacitor, the connection node of the third switching unit and the fourth switching unit connected to a negative node (−

) of the DC link capacitor and being a common ground terminal.

10. The rectifying and power factor correction unit as in claim 6, wherein the energy storing inductor L_PFC has two sets,one connected in series between the first output terminal and the second load terminal;

and the other one connected in series between the second output terminal and the first load terminal.

11. The rectifying and power factor correction unit as in claim 6, wherein the first output terminal of the first rectifier is directly connected to the first load terminal, the second output terminal of the second rectifier is directly connected to the second load terminal.

12. The rectifying and power factor correction unit as in claim 6, wherein the first output terminal of the first rectifier is connected to the second output terminal of the second rectifier and then connected to the first or second load terminal.

13. The rectifying and power factor correction unit as in claim 6, wherein the first output terminal of the first rectifier is connected to the second output terminal of the second rectifier and then connects the energy storing inductor L_PFC to the first or second load terminal.

14. The rectifying and power factor correction unit as in claim 6, wherein the first output terminal of the first rectifier is connected to the second output terminal of the second rectifier, and then connected to a energy storing inductor, the energy storing inductor then connects a fifth diode to the second load terminal in series, and also connects a sixth diode to the first load terminal in series.