DC-DC converter and a regulation method for this DC-DC converter

• US 6,711,034 B2
• Filed: 09/03/2002
• Issued: 03/23/2004
• Est. Priority Date: 09/04/2001
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Sauerlaender, Georg, Elferich, Reinhold, Duerbaum, Thomas
• Primary Examiner(s): Berhane, Adolf D.
• Application Number:
  US10/233,451
• Publication Number:
  US 20030043599A1
• Time in Patent Office: 567 Days
• Field of Search: 363/16, 363/78, 363/95, 363/97, 363/131
• US Class Current: 363/16
• CPC Class Codes: H02M 3/3376 with automatic control of output voltage or current
• CPC Class Codes: H02M 7/4803 with means for reducing DC component from AC output voltage

Abstract

A DC—DC converter includes an inverter and a primary-side circuit with a transformer whose secondary-side voltage is rectified by at least one rectifier for generating an output DC voltage. To avoid an asymmetrical load, which is in particular exhibited by a different load of the rectifier elements (power semiconductors), an electrical magnitude of the DC—DC converter is measured. This magnitude may be, for example, a primary-side current, a primary-side voltage at a capacitance, or a secondary-side, rectified voltage. A parameter for the symmetry deviation is calcuted from the measurement of the magnitude. A symmetry regulation arrangement utilizes the drive of the inverter, for example, the duty cycle of the pulse-width modulated voltage produced by the inverter to minimize the parameter for the symmetry deviation. This achieves an even distribution of the power over the secondary rectifier elements.

Claims

1. A DC—

DC converter comprising;

an inverter for generating a switched AC voltage;

a primary-side circuit coupled to said inverter for receiving said switched AC voltage, said primary-side circuit including a primary side of a transformer, said transformer having a secondary side including at least one rectifier for generating at least an output DC voltage;

a measuring unit for measuring an electrical magnitude of the DC—

DC converter;

a symmetry calculation unit for calculating, from the measured electrical magnitude, a parameter for a symmetry deviation of the electrical magnitude; and

a symmetry regulation unit for changing a drive of the inverter in

dependence on the calculated parameter for the symmetry deviation so that the symmetry deviation is minimized.

2. The DC—

DC converter as claimed in claim 1, in wherein the DC—

DC converter further comprises means for driving

the inverter so that the inverter supplies a pulse-width modulated voltage, and

wherein the symmetry regulation device regulates the driving means to control the duty cycle of the pulse width modulated AC voltage whereby the symmetry deviation goes to zero.

3. The DC—

DC converter as claimed in claim 1, wherein the primary-side circuit is a resonance arrangement comprising at least one capacitance.

4. The DC—

DC converter as claimed in claim 1,

wherein the measuring arrangement measures a primary-side current at the transformer.

5. The DC—

DC converter as claimed in claim 3,

wherein the measuring arrangement measures a voltage (vC) at the primary-side capacitance.

6. The DC—

DC converter as claimed in claim 1,

wherein the measuring arrangement measures a rectified secondary-side electrical magnitude.

7. The DC—

DC converter as claimed in claim 1,

wherein the symmetry calculation unit calculates an intermediate magnitude from the measured electrical magnitude.

8. The DC—

DC converter as claimed in claim 1,

wherein the symmetry calculation unit calculates a magnitude as a parameter for the symmetry deviation, said magnitude depending on a difference between a negative and a positive peak value of at least one of the electrical magnitudes.

9. The DC—

DC converter as claimed in claim 1,

wherein the symmetry calculation unit produces a magnitude as a parameter for the symmetry deviation, said magnitude being calculated from a difference between values

of a deviation of a maximum of at least one of the electrical magnitudes from a mean value of the electrical magnitude,

and a deviation of a minimum of at least one of the electrical magnitudes from the mean value of the electrical magnitude.

10. The DC—

DC converter as claimed in claim 1,

wherein the symmetry measuring arrangement calculates a magnitude as a parameter for the symmetry deviation in accordance with the following expression;

11. The DC—

DC converter as claimed in claim 1,

wherein the symmetry measuring unit calculates a magnitude as a parameter for the symmetry deviation from a difference between values

of a first extreme of an electrical magnitude within a first time interval,

and of a second extreme of the electrical magnitude within a second time interval.

12. A switched-mode power supply comprising:

a power supply input circuit for connection to a voltage supply and for generating an intermediate circuit DC voltage; and

a DC—

DC converter as claimed in claim 1 coupled to receive the intermediate circuit DC voltage.

13. A method for regulating a DC—

DC converter, said method comprising the steps;

generating a switched AC voltage from an applied DC voltage;

applying the switched AC voltage to a primary-side circuit comprising the primary side of a transformer;

rectifying a voltage induced on the secondary side of the transformer to form at least one output DC voltage;

measuring an electrical magnitude of the DC—

DC converter;

calculating a parameter for a symmetry deviation of the electrical magnitude; and

regulating a drive of the inverter so as to minmize the symmetry deviation of the electrical magnitude.