Inverter for conversion of electrical energy

• US 6,449,181 B1
• Filed: 05/30/2001
• Issued: 09/10/2002
• Est. Priority Date: 10/01/1999
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Rieger, Reinhard, Reutlinger, Kurt
• Primary Examiner(s): Patel, Rajnikant B.
• Application Number:
  US09/856,997
• Time in Patent Office: 468 Days
• Field of Search: 363/159, 363/144, 363/143, 363/132, 363/56, 363/141, 363/37, 361/321.01, 361/321.02, 361/328
• US Class Current: 363/159
• CPC Class Codes: H02M 7/493 the static converters being arranged for operation in parallel

Abstract

Frequency converters for converting electrical energy, in particular for a vehicle electrical system, are proposed which have individual partial frequency converters and include at least one half bridge, as a result of which there are at least one high-side switch and one low-side switch with a predeterminable number of switches. The high-side switch and low-side switch have a common connection that is connected to means that produce the electrical energy. Parallel to the half bridge, there is an intermediary circuit capacitor whose capacitance should be as low as possible. To this end, the switches of the half bridge are triggered offset from one another so that the current to be supplied by the intermediary circuit capacitor remains as low as possible. Various possibilities are disclosed for the arrangement of the chokes of the frequency converter.

Claims

1. A frequency converter for converting electrical energy, in particular for a vehicle electrical system, having at least one half bridge which includes at least one high-side switch and one low-side switch with a predeterminable number of switches which have a common connection that is connected to means that produce the electrical energy and having a capacitor that is disposed parallel to the half bridge, further comprising control means, wherein said control means perform an offset control of the switches such that the switches are triggered offset from one another, wherein the offset triggering of the switches takes place within a branch of the bridge by selection of a high to low keying ratio, thereby providing a minimal load on the capacitor.

2. The frequency converter according to claim 1, wherein the means for producing the electrical energy are an electrical machine, in particular a generator or a starter/generator.

3. The frequency converter according to claim 1, wherein the means for producing the electrical energy are a three-phase generator with three phase windings, each with a predeterminable number k of parallel windings, that the frequency converter is a three-phase frequency converter which includes three identical half bridges with twice the number k of switches which are triggered in an offset fashion.

4. The frequency converter according to claim 1, wherein the high-side switches and low-side switches include field effect transistors, bipolar transistors, or pulse inverter elements which are triggered with the aid of said control means and regulating device and in particular, are operated in a pulse-to-width modulated manner.

5. The frequency converter according to claim 1, wherein the connection between the common connection of the high-side and the low-side switches and the means that produce the electrical energy respectively has at least one inductance.

6. The frequency converter according to claim 5, wherein the inductances are disposed as longitudinal chokes in series between mutually associated switches or are disposed as lateral chokes between four respective switches.

7. The frequency converter according to claim 1, wherein the half bridge is embodied and operated so that it functions as a direct current converter and in addition to the intermediary circuit capacitor at the output, has an additional capacitor at which a voltage occurs that differs from the voltage at the intermediary circuit capacitor.

8. The frequency converter according to claim 1, wherein the pulsed triggering of the switches takes place with pulse-to-width modulated signals with a keying ratio high to low which is selected so that the intermediary circuit capacitor is only slightly loaded and in particular, is equal to {fraction (2/8)}, {fraction (4/8)}, and {fraction (6/8)}.

9. The frequency converter according to claim 1, wherein the individual partial frequency converters are combined into separate modules and are integrated into the machine housing.

10. The frequency converter according to claim 1, wherein the required chokes are embodied as singly coupled chokes or as compensated chokes.

11. The frequency converter according to claim 1, wherein the required chokes are embodied as multi-phase chokes and are disposed in a parallel arrangement, in a circular arrangement, or in a star-shaped arrangement, and have respectively adapted yokes.

12. The frequency converter according to claim 1, wherein the windings of the electrical machine have two parallel wires or two winding stars.