Power supply system

• US 6,917,531 B2
• Filed: 05/28/2002
• Issued: 07/12/2005
• Est. Priority Date: 05/29/2001
• Status: Expired due to Fees

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Scheel, Thomas, Hattrup, Christian, Maertens, Olaf, Gercke, Thorsten
• Primary Examiner(s): Laxton, Gary L
• Application Number:
  US10/478,034
• Publication Number:
  US 20040125624A1
• Time in Patent Office: 1,141 Days
• Field of Search: 363/65, 363/67, 363/71, 363/97, 363/98, 363/131, 363/132, 363/15, 363/16, 363/21.02, 363/95
• US Class Current: 363/97
• CPC Class Codes: H02M 1/0012 Control circuits using digital or numerical techniques in DC/DC converters H02M3/157, H02M3/33515; in DC-AC converters H02M7/53873
• CPC Class Codes: H02M 7/5236 in a series push-pull arrangement
• CPC Class Codes: H05G 1/10 Power supply arrangements for feeding the X-ray tube supply circuits with converters in general H02M; supply circuits for emitters and amplifiers H04B1/16 - H04B1/1623
• CPC Class Codes: H05G 1/58 Switching arrangements for changing-over from one mode of operation to another, e.g. from radioscopy to radiography, from radioscopy to irradiation or from one tube voltage to another

Abstract

Two proposals are made for power supply systems comprising at least one resonant inverter and one control unit. According to the first proposal the power supply system comprises two inverters and produces two output voltages, the control circuit processing as an actual value on the one hand the sum of and on the other hand the difference between the two output voltages. According to the second proposal a control circuit does not directly process the controlled variables for a power supply system comprising at least one inverter, but difference units for controlled variables determine the deviations from a preceding sampling instant and these difference values are processed. Also the correcting variable calculated in this way is a difference value which is converted into a correcting variable value by a correcting variable summing unit. The two proposals can be advantageously combined. As an important improvement is proposed the use of a limiting controller which generally becomes active in case of imminent transgression of a maximum value and which limits the actuation. The control circuit is preferably used as a digital control circuit for a state space control.

Claims

1. A power supply system comprising:

a first and a second inverter for generating switched first and second inverter output voltages, respectively,

a resonant circuit fed by the inverters, the circuit comprising at least one transformer and at least one resonant capacitor

first and second resonant circuit output voltages generated on the secondary side of the transformer,

a control circuit which processes;

a first actual value that depends on the sum of the first and second resonant circuit output voltages, and

a second actual value that depends on the difference between the first and second resonant circuit output voltages,

the control circuit pedefining driving magnitudes as correcting variables for the inverters.

2. A power supply system as claimed in claim 1, in which

the control circuit is arranged so that the sum of the first and second resonant circuit output voltages is adjusted to a sum set value, and

the difference between the first and second resonant circuit output voltages is adjusted to a difference set value.

3. A power supply system as claimed in claim 1, in which

the control circuit additionally processes a third resonant circuit and a fourth actual value,

the third and fourth actual values depending on primary-side resonant currents that flow through the resonant circuit fed by the inverters.

4. A power supply system as claimed in claim 3, in which

a parameter is formed for a first and a second resonant capacitance voltage from the primary-side resonant currents by integration and subsequent value formation,

the third actual value depends on the sum of the resonant capacitance voltages and

the fourth actual value depends on the difference between the resonant capacitance voltages.

5. A power supply system as claimed in claim 1, in which the control circuit predefines values as driving magnitudes for the inverters, which predefined values each define the duty cycle.

6. A power supply system as claimed in claim 5, in which

the control circuit determines a sum and a difference of the predefined values, the driving magnitudes for the inverters being calculated from the sum and difference.

9. A power supply system as claimed in claim 1, in which

the control circuit has at least one controlled variable difference unit which determines a difference value between controlled variables, which difference value depends on a difference between the current sample value of a controlled variable and at least one preceding sample value of the controlled variable, and

the control circuit delivers a correcting variable difference value as a correcting variable, the control circuit including a correcting variable summing unit which unit determines a correcting variable value which correcting variable value is formed from a preceding correcting variable and the delivered correcting variable difference value.

10. A power supply system as claimed in claim 1, in which the control circuit is a digital control circuit for a state space control.

11. A power supply system as claimed in claim 1, comprising means for limiting a primary-side resonant current.

7. A power supply system comprising:

at least one inverter for generating a switched inverter output voltage,

a resonant circuit fed by the inverter, the resonant circuit comprising at least one transformer and at least one resonant capacitance at least one output voltage being generated on the secondary side of the transformer, and

a control circuit for adjusting the output voltage to a set value, the control circuit delivering driving values for the inverters as correcting variables,

the control circuit including;

at least one controlled variable difference unit which determines a difference value, which difference value depends on a difference between a current sample value of a controlled variable and at least one preceding sample value of the controlled variable, a correcting variable difference value being delivered as a correcting variable, and

a correcting variable summing unit which unit determines a correcting variable from a preceding correcting variable and the delivered correcting variable difference value.

8. A power supply system as claimed in claim 7, in which the inverter comprises:

means for changing over between a first operating mode and a second operating mode

a resonant circuit formed by at least one resonant capacitance and one transformer being active in the first operating mode at the output of the inverter, and

a series combination including at least one inductance connected in series to the resonant circuit being active in the second operating mode at the output.