Electronic circuit for easier operation of multilevel converters

Patent metadata

Field	Value
Publication number	US-10473728-B2
Application number	US-201515318057-A
Country	US
Kind code	B2
Filing date	Jun 3, 2015
Priority date	Jun 13, 2014
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

Prior art electronic power supplies having distributed energy stores and/or the possibility to dynamically modify the connectivity of individual stores require complex monitoring of the input and output currents to and from the individual energy stores, often using a multitude of sensors, in order to allow for unrestricted operation. Examples of such power supplies include in particular modular multilevel converters and switched-capacitor circuits. The preen invention describes a possibility to determine the states of charge and energy levels of the energy stores using a small number of measuring systems.

First claim

The invention claimed is:

1. An electrical circuit comprising:
at least two plurality of modules which each have at least one electrical energy store and at least one electronic switch configured to change electrical connections of the at least one electrical energy store to the energy stores of other modules of the plurality of modules, and
at least one voltage-measuring device, coupled to the plurality of modules, configured to measure an electrical voltage generated by a group of two or more of the plurality of modules, in at least two different switched states s(t) of the modules within the group, and to automatically determine voltages of the electrical energy stores of the individual modules within the group from the electrical voltages generated by the group,
wherein:
the two or more modules each bring about at least two switched states which each define how the energy stores of the two or more modules are connected to one another in an electrically conductive fashion wherein one group of modules contains at least two or all of the modules of the electrical circuit, and
the electrical circuit:
(i) combines the automatically determined voltages of the electrical energy stores of the individual modules as coordinates in a vector V(t), and
(ii) maps the automatically determined voltages as an electrical voltage V unit s(t) from the measured electrical voltage generated by the group at a respective time (t) as modeled by a matrix M(s(t)) that is a function of the at least two different switched states s(t), such that V unit (s(t))=M(s(t)) dot product V(t).

2. The electrical circuit as claimed in claim 1 , wherein the two or more modules each bring about at least two of the following three switched states:
the at least one electrical energy store of a module is connected in series with the at least one energy store of another module using electrical switches;
the at least one electrical energy store of a module is connected in parallel with the at least one energy store of another module using electrical switches;
the at least one electrical energy store of a module is bypassed using electrical switches, which means that the at least one electrical energy store of a module is connected in an electrically conductive manner at maximum by just one of its at least two electrical contacts to an electrical energy store of another module, and therefore there is no closed circuit with an electrical energy store of another module.

3. The electrical circuit as claimed in claim 1 , wherein the voltages of the electrical energy stores of at least two modules are determined in at least one estimation time by at least one integrated electronic circuit.

4. The electrical circuit as claimed in claim 3 , wherein the at least one integrated electronic circuit estimating time receives, as input signals, at least one digitized measurement signal of the electrical voltage generated by the group of modules, from a measuring unit, and receives at least one signal describing a current module state from at least one control unit.

5. The electrical circuit as claimed in claim 4 , wherein the time estimation is carried out by the integrated electronic circuit according to a digital clock cycle at fixed time increments.

6. The electrical circuit as claimed in claim 5 , wherein the at least one integrated circuit for estimating time contains at least one digital memory module which stores at least the module states and the measured values of the generated electrical voltages of a group of a plurality of modules of a plurality of elapsed digital clock cycles.

7. The electrical circuit as claimed in claim 4 , wherein the at least one integrated circuit for estimating time transmits at least one signal which describes the estimated module voltages of the individual modules.

8. The electrical circuit as claimed in claim 1 , wherein the voltage-measuring device also measures, in addition to the voltage, the electrical current flowing into the group of modules, and uses it for the automatic determination of the module voltages of the individual modules.

9. The electrical circuit as claimed in claim 1 , wherein the voltage-measuring device also comprises at least two voltage-measuring apparatuses, each of which measures the electrical voltages, generated by a respectively associated group of a plurality of modules, in at least two different switched states, wherein individual modules are part of a plurality of groups associated with the specified, in each case, at least one voltage-measuring apparatus; and wherein an estimation error of the determined voltages of the electrical energy stores of the individual modules is determined with the at least two voltage-measuring apparatuses, or a technical failure of at least one of the at least two voltage-measuring apparatuses is detected.

10. The electrical circuit as claimed in claim 1 , wherein the device also contains at least one temperature-measuring apparatus which measures a temperature of a module or at least of an electronic switch of a module or at least of an electrical energy store of a module or of a group of a plurality of modules.

11. A method for determining a respective voltage of a multiplicity of electrical energy stores, wherein in each case at least one electrical connection between individual energy stores is separated from one another by, in each case, at least one disconnecting electrical switching element, and wherein the multiplicity of electrical energy stores and disconnecting electrical switching elements are part of a modular electrical circuit, comprising at least the following steps which are carried out in a cyclically repeating fashion:
measuring a respective electrical voltage formed by connection of the specified multiplicity of electrical energy stores in each of at least two different switched states s(t) of the specified disconnecting electrical switching elements;
digitizing the specified measured electrical voltages;
transmitting the digitized measured electrical voltages to at least one integrated electrical circuit; and
estimating respective voltages of each of the multiplicity of electrical energy stores from the digitized measured electrical voltages for the specified multiplicity of electrical energy stores and the switched states which are associated with the specified disconnecting electrical switching elements utilizing the at least one integrated electrical circuit by:
(i) combining the digitized measured electrical voltages for the specified multiplicity of electrical energy stores as coordinates in a vector V(t); and
(ii) mapping the digitized measured electrical voltages as an electrical voltage V unit s(t) from the measured respective electrical voltage for the specified multiplicity of electrical energy stores at a respective time (t) as modeled by a matrix M(s(t)) that is a function of the at least two different switched states s(t), such that V unit (s(t))=M(s(t)) dot product V(t).

Assignees

• Porsche Ag

Inventors

• Goetz Stefan

Classifications

• H02J7/575

  Parallel/serial switching of connection of batteries to charge or load circuit · CPC title

• H02M7/483 Primary

  Converters with outputs that each can have more than two voltages levels · CPC title

• H02M2007/4835

  Electricity · mapped topic

• G01R31/40 Primary

  Testing power supplies (testing photovoltaic devices H02S50/10) · CPC title

• H02J7/0024

  Electricity · mapped topic