DC-to-DC voltage converter, voltage supply device, and diagnostic method for a DC-to-DC voltage converter

Patent metadata

Field	Value
Publication number	US-10988028-B2
Application number	US-201816495572-A
Country	US
Kind code	B2
Filing date	Mar 16, 2018
Priority date	Mar 31, 2017
Publication date	Apr 27, 2021
Grant date	Apr 27, 2021

Abstract

A diagnosis method for the switching elements in a bidirectional DC-to-DC voltage converter comprising: charging a capacitor in the bidirectional DC-to-DC voltage converter to a predetermined first test voltage, then specifically actuating the switching elements in the bidirectional DC-to-DC voltage converter, and evaluating the voltage in the charged capacitor of the bidirectional DC-to-DC converter to identify a faulty switching element within the switching elements in the bidirectional DC-to-DC voltage converter.

First claim

What is claimed is:

1. A diagnostic method for a bidirectional DC-to-DC voltage converter that comprises a first capacitor (C 1 ) and a first full bridge ( 1 ) at a first DC voltage terminal ( 10 ) and that comprises a second full bridge ( 2 ) at a second DC voltage terminal ( 20 ), wherein the first full bridge ( 1 ) comprises two half bridges ( 11 , 12 ) each having a first switching element (M 1 , M 2 ) and a second switching element (M 3 , M 4 ), comprising the steps of:
providing (S 1 ) a first DC voltage at the second DC voltage terminal ( 20 ) of the bidirectional DC-to-DC voltage converter;
opening (S 2 ) the first switching elements (M 1 , M 2 ) and the second switching elements (M 3 , M 4 ) of the first full bridge ( 1 );
charging (S 3 ) the first capacitor (C 1 ) to a predetermined first test voltage by driving the second full bridge ( 2 );
closing (S 4 ) one of the first switching elements (M 1 , M 2 ) of the first full bridge ( 1 );
detecting (S 5 ) a faulty second switching element (M 3 , M 4 ) if the electric voltage across the first capacitor (C 1 ) drops by more than a predefined first voltage value within a predetermined first time interval following the closure of the first switching element (M 1 , M 2 );
opening (S 6 ) the closed first switching element (M 1 , M 2 ) of the first full bridge ( 1 );
closing (S 7 ) one of the second switching elements (M 3 , M 4 ) of the first full bridge ( 1 ); and
detecting (S 8 ) a faulty first switching element (M 1 , M 2 ) if the electric voltage across the first capacitor (C 1 ) drops by more than a predefined second voltage value within a predetermined second time interval following the closure of the second switching element (M 3 , M 4 ).

2. The diagnostic method as claimed in claim 1 , wherein the steps of opening (S 6 ) the closed first switching element (M 1 , M 2 ), of closing (S 7 ) the second switching element (M 3 , M 4 ) and of detecting (S 8 ) a faulty first switching element (M 1 , M 2 ) are performed only if no faulty second switching element (M 3 , M 4 ) has been detected.

3. The diagnostic method as claimed in claim 1 , comprising a step of charging the first capacitor (C 1 ) to a predetermined second test voltage after the closed first switching element (M 1 , M 2 ) has been opened.

4. The diagnostic method as claimed in claim 3 , wherein the predetermined second voltage to which the first capacitor (C 1 ) is charged is determined depending on a maximum forward current, a maximum operating temperature and/or a maximum heat dissipation of the first switching elements (M 1 , M 2 ) and/or of the second switching elements (M 3 , M 4 ) in the first full bridge ( 1 ).

5. The diagnostic method as claimed in claim 1 , wherein the predetermined first voltage to which the first capacitor (C 1 ) is charged is determined depending on a maximum forward current, a maximum operating temperature and/or a maximum heat dissipation of the first switching elements (M 1 , M 2 ) and/or of the second switching elements (M 3 , M 4 ) in the first full bridge ( 1 ).

6. The diagnostic method as claimed in claim 1 , comprising a step of identifying the faulty switching element (M 1 . . . M 4 ) if a faulty first switching element (M 1 , M 2 ) or a faulty second switching element (M 3 , M 4 ) has been detected.

7. The diagnostic method as claimed in claim 1 , wherein the value of the first test voltage to which the first capacitor (C 1 ) is charged is greater than the value of the first DC voltage that is provided at the second DC voltage terminal ( 20 ).

8. The diagnostic method as claimed in claim 1 , comprising a step of activating the bidirectional DC-to-DC voltage converter if no faulty first switching element (M 1 , M 2 ) and no faulty second switching element (M 3 , M 4 ) has been detected.

9. A DC-to-DC voltage converter for a bidirectional DC-to-DC voltage conversion between a first DC voltage terminal ( 10 ) and a second DC voltage terminal ( 20 ), having:
a first capacitor (C 1 ) that is electrically coupled to the first DC voltage terminal ( 10 );
a first full bridge ( 1 ) that is electrically coupled to the first DC voltage terminal ( 10 ) and that comprises two half bridges ( 11 , 12 ) each having a first switching element (M 1 , M 2 ) and a second switching element (M 3 , M 4 );
a second full bridge ( 2 ) that is electrically coupled to the second DC voltage terminal ( 20 ); and
a controller ( 7 ) that is designed to open the first switching elements (M 1 , M 2 ) and the second switching elements (M 3 , M 4 ) of the first full bridge ( 1 ), to charge the first capacitor (C 1 ) by driving the second full bridge ( 2 ) at a predetermined first test voltage, to then close one of the first switching elements (M 1 , M 2 ) in the first full bridge ( 1 ) and to detect a faulty second switching element (M 3 , M 4 ) in the first full bridge ( 1 ) if the electric voltage across the first capacitor (C 1 ) drops by more than a predefined first voltage value within a predetermined first time interval following the closure of the first switching element (M 1 , M 2 ), to then open the closed first switching element (M 1 , M 2 ) in the first full bridge ( 1 ), to close one of the second switching elements (M 3 , M 4 ) in the first full bridge ( 1 ) and detect a faulty first switching element (M 1 , M 2 ) if the electric voltage across the first capacitor (C 1 ) drops by more than a predefined second voltage value within a predetermined second time interval following the closure of the second switching element (M 3 , M 4 ).

10. The DC-to-DC voltage converter as claimed in claim 9 , having a transformer ( 3 ) that is electrically coupled to the first full bridge ( 1 ) by way of a primary side and electrically coupled to the second full bridge ( 2 ) by way of a secondary side.

11. A voltage supply device for an electric or hybrid vehicle having:
a high-voltage on-board system that is designed to provide electrical energy at a first predetermined electric voltage;
a low-voltage on-board system that is designed to provide electrical energy at a second predetermined electric voltage;
a DC-to-DC voltage converter as claimed in claim 9 , wherein the first DC voltage terminal ( 10 ) of the DC-to-DC voltage converter is able to be electrically coupled to the high-voltage on-board system, and the second DC voltage terminal ( 20 ) of the DC-to-DC voltage converter is electrically coupled to the low-voltage on-board system.

Assignees

• Bosch Gmbh Robert

Inventors

• Jin Jiahang

Classifications

• H02M3/18

  using capacitors or batteries which are alternately charged and discharged, e.g. charged in parallel and discharged in series · CPC title

• H01H2047/003

  Detecting welded contacts and applying weld break pulses to coil · CPC title

• B60L2240/547

  Voltage · CPC title

• B60L3/003 Primary

  relating to inverters · CPC title

• B60L2240/52

  related to converters · CPC title