WO2010124988A1

WO2010124988A1 - Control device for controlling at least one rectifier element of a voltage converter

Info

Publication number: WO2010124988A1
Application number: PCT/EP2010/055363
Authority: WO
Inventors: Alexander Ehret; Peter Maisel; Martin Saliternig
Original assignee: Conti Temic Microelectronic Gmbh
Priority date: 2009-04-28
Filing date: 2010-04-22
Publication date: 2010-11-04

Abstract

The invention relates to a control device (38) for controlling at least one rectifier element (26, 28) of a voltage converter (10), the voltage converter (10) comprising a control unit (12) and a rectifier unit (16) having the at least one rectifier element (26, 28). Said control device is designed to control the at least one rectifier element (26, 28) independently from the control unit (12).

Description

description

Control device for controlling at least one rectifying element of a voltage converter

The invention relates to a control device for controlling at least one rectifying element of a voltage converter.

The invention further relates to a vehicle.

The invention further relates to a method for controlling at least one rectifying element of a voltage converter.

The invention further relates to a computer-readable storage medium.

The invention further relates to a program element for controlling at least one rectifying element of a voltage converter.

Voltage transformers can be designed with galvanic isolation or without galvanic isolation. Typically, a voltage converter with a galvanic isolation on a switching unit with switching elements, a transformer unit for transforming a voltage of the switching unit and a downstream rectifying unit with at least one rectifying element. An input DC voltage of the voltage converter is converted via the switching elements of the switching unit into an AC voltage. The generated AC voltage is transmitted via the transformer unit to the rectifier unit, which converts the transformed AC voltage into a DC output voltage whose magnitude is different from a magnitude of the input voltage. Voltage transformers without galvanic isolation have a switching unit with a switching element and a downstream Rectifying unit with a rectifying element on. An input DC voltage of a certain size is converted into a DC output voltage of a different size by means of the switching element and the rectification element.

If the voltage converter is operated in the low setting position, the output voltage is reduced with respect to the input voltage. In a step-up operation of the voltage converter, the input voltage of the voltage converter is converted into a larger output voltage.

A switching element of the switching unit and / or a rectifying element of the rectifying unit are usually used as semiconductor switches, for example MOSFETs (metal oxide semiconductor field effect transistors) or IGBTs (bipolar transistors).

Insulated gate transistors).

To increase the efficiency of the voltage converter, it is well known to operate the switching element of the switching unit by zero voltage switching (ZVS) or zero current switching (ZCS) switching. In these two techniques, the switching element is driven so that it is switched on or off at the time of voltage or current zero crossing. A shift in switching times of the switching element induced by these techniques is transferred to switching times of the rectification element, since a drive of the switching element is usually connected by a logic operation to a drive of the rectification element. This linkage can, for example, cause the rectification element to be switched on or off at an unfavorable or incorrect time, so that short circuits in the voltage converter and / or high stress of the semiconductor rectification element may occur.

US Pat. No. 7,443,142 B2 discloses an electrical system for a vehicle which has a battery and a generator for generating electricity and a rectification unit with a plurality of rectifying elements. The rectifier elements can be controlled by a microprocessor which uses an output voltage and an output current of the electrical system as measurement parameters.

The known electrical system is not a voltage converter with a switching unit.

The invention has for its object to provide a driving a rectifying element of a voltage converter in the simplest possible way.

This object is solved by the subject matter of the independent patent claims. Advantageous embodiments of the present invention are described in the dependent claims.

According to a first aspect of the invention, a control device is provided for controlling at least one rectifying element of a voltage converter, wherein the voltage converter has a switching unit and a rectifying unit with the at least one rectifying element, wherein the control device is designed to separate the at least one rectifying element independently of the switching unit head for .

According to another aspect of the invention, there is provided a vehicle including such a control device has at least one rectifying element of a voltage converter of the vehicle.

According to yet another aspect of the invention, there is provided a method of controlling at least one rectifying element of a voltage converter, the voltage converter comprising a switching unit and a rectifying unit having the at least one rectifying element, the at least one rectifying element being controlled independently of the switching unit.

According to yet another aspect of the invention, there is provided a computer-readable storage medium having stored thereon a program for controlling at least one rectifying element of a voltage converter which, when supplied from a

Processor is executed, for performing the method for controlling at least one rectifying element of a voltage converter is set up.

In accordance with yet another aspect of the invention, there is provided a program element for controlling at least one rectifying element of a voltage converter which, when executed by a processor, is adapted to perform the method of controlling at least one rectifying element of a voltage converter.

The vehicle, the method, the computer-readable storage medium, and the program element according to the further aspects of the invention may have the same effects and advantages as the control device according to the one aspect of the invention.

The control device may be adapted to the switching unit, for example at least one switching element of Switching unit, and to drive the at least one rectifying element of the rectifying unit.

The control device may be designed to control the at least one rectifying element of the rectifying unit, but not the switching unit.

A "driving of the at least one rectifying element" is understood to mean that the control device generates a control signal for switching the rectification element on and / or off, which is supplied to the rectifying element.

One of the switching unit, for example of at least one switching element of the switching unit, "independent" driving the rectifying element is to be understood that the control device generates such a control signal for the at least one rectifying element that the switching times of the rectifying element of the rectifying unit not with the switching times of the switching unit are coupled.

The ability to control the rectifying element independently of the switching unit causes an increase in the efficiency of the voltage converter, since a time unfavorable or incorrect switching of the rectifying element is avoided due to a combination of the control signals of the switching unit and the rectifying element, which could lead to line losses.

In addition, a material stress of the rectifying element, which is based for example on a semiconductor material, is avoided in the case of its unfavorable or false switching, so that the life of the rectifying element is achieved. is increased. In this sense, also reduce the cost of replacing individual components or the total cost of a system in which the voltage converter is integrated.

The control device also allows a high degree of flexibility in the setting of the control of the at least one rectifying element, since the control of the at least one rectifying element is adjustable independently of the control of the switching unit.

The voltage converter is also structurally very simple, since signal processing elements omitted, which usually ensure a logical connection of the switching signals of the switching unit with those of the rectifying element of the rectification unit.

The voltage converter can be used in many ways, since the voltage converter can be designed, for example, with or without galvanic isolation.

The controller may also be readily implemented in all actively switched voltage transformer topologies, such as hard-switching, soft-switching or resonant-switching voltage transformer topologies, with active (synchronous) rectification.

The control device can be designed to control the at least one rectifying element with a time delay to the switching unit. Such a time offset between, for example, the switching times of the switching unit and the rectifying element ensures that an actuation of the switching unit does not provide optimal control of the rectifying element. can affect, so that the operation of the voltage converter is not adversely affected.

The time offset can be a dead time.

A time offset between a driving of the switching unit and a driving of the at least one rectifying element may be a time-fixed time offset. This allows a particularly simple control of the rectifying element, since a once predetermined control signal during the entire operation of the voltage converter does not need to be changed in order to achieve optimum control of the at least one rectifying element.

A time offset between a driving of the switching unit and a driving of the at least one rectifying element may be a time-variable time offset depending on a characteristic of the voltage converter. This measure offers a possibility of readjusting the rectifier element if a parameter of the voltage converter changes.

A parameter may be selected from a group consisting of an input voltage of the voltage converter, an input current of the voltage converter, an output voltage of the voltage converter, an output current of the voltage converter and a

Duty cycles of the at least one rectifying element to be selected. These parameters represent typical values of the voltage converter which are easily detectable and thus available as control parameters for controlling the at least rectifying element.

The control device may comprise an element for generating a control of the switching unit and an element for generating a control of the at least one rectifying element. point. This structurally very simple embodiment of the control device can generate a control signal for the switching unit and a time-offset control signal for the at least one rectifying element. The element for generating an activation of the at least one rectification element can be based on digital and / or use information about the actuation of the switching unit in order to provide the drive of the at least one rectification element.

The element for generating a control of the switching unit and / or the element for generating a control of the at least one rectifying element can be designed based on digital.

The rectification unit may have at least one further rectifying element, wherein the control device is designed to control the at least one further rectifying element independently of the switching unit. Voltage transformers can have a rectification unit with a plurality of rectifier elements, for example semiconductor switches. Actuation of the at least one and the at least one further rectifying element, independently of a triggering of the switching unit, causes both rectifying elements to switch to an optimum time. This can significantly increase the efficiency of the voltage converter.

The control device can be designed to control the at least one further rectifying element independently of the at least one rectifying element. As a result, the efficiency of the voltage converter is increased because each rectifying element can be optimally controlled.

In order to control the at least one further rectifying element, the control device may additionally or alternatively be connected to a Characteristic of the voltage converter to use information about a control of the at least one rectifying element.

It should be noted that embodiments of the invention have been described with reference to different subject matters. In particular, some embodiments of the invention are described with apparatus claims and other embodiments of the invention with method claims. However, it will be readily apparent to those skilled in the art upon reading this application that, unless explicitly stated otherwise, in addition to a combination of features belonging to a type of subject matter, any combination of features is possible to differentiate Types of inventions include.

Further advantages and features of the present invention will become apparent from the following exemplary description of presently preferred embodiments. The individual figures of the drawing of this application are merely to be regarded as schematic and not to scale.

1 shows a voltage converter in the low setting position with a control device according to a first exemplary embodiment.

FIG. 2 shows time profiles of voltages and currents of a transformer unit and of rectifier elements of the voltage converter in FIG. 1 in an operation of the control device.

3 shows the control device in FIG. 1. FIG. 4 shows time profiles of voltages of switching elements and the rectification elements of the voltage converter in FIG. 1.

5 shows a further voltage converter with a control device according to a second exemplary embodiment.

FIG. 6 shows time profiles of voltages of a switching and rectifying element of the voltage converter in FIG. 5 in an operation of the control device.

FIG. 7 shows further time profiles of voltages of the switching and rectifying element of the voltage converter in FIG. 5 in a further operation of the control device.

It should be noted that features or components of different embodiments that are the same or at least functionally identical with the corresponding features or components of the embodiment, are provided with the same reference numerals. In order to avoid unnecessary repetitions, features or components already explained on the basis of a previously described exemplary embodiment will not be explained in detail later.

1 shows a voltage converter 10 with a switching unit 12, a transformer unit 14 and a rectifying unit 16. The switching unit 12 has four switching elements 18-24 in full-bridge topology, which are designed as field-effect transistors. Two rectifying elements 26, 28 of

Rectifying unit 16 are also formed as field effect transistors. Usually, the timing of the rectification elements 26, 28 connected via a logical link with the timing of the switching elements 18-24. A time profile of voltages and currents of the rectification elements 26, 28 thus results from the temporal

Course of voltages and currents of the switching elements 18-24, which are transmitted by means of the transformer unit 16 to the rectifying elements 26, 28. In order to produce no or low switching loss losses in the switching unit 12, the switching elements 18-24 are connected in their respective voltage zero crossing (ZVS).

As shown in Fig. 2, transmits the transformer unit 14 at a drive (push-pull, Phaseshift, etc.) of the switching elements 18-24 an AC voltage 30 and a

AC 32. In order to rectify this rectangular voltage 30 or this current 32 with simultaneous driving of the switching elements 18-24, the rectifying elements 26, 28 are driven so that shown in Fig. 2 temporal courses of gate voltages 34a, b and currents 36a, b of the rectifying elements 26, 28. The voltage converter 10 has time periods t ₂ <t <t ₃ and t ₅ <t <tβ current peaks of the rectifying elements 26, 28, which indicate short circuits of the voltage converter 10 during these time periods. Thereby, the semiconductor rectifying elements 26, 28 and in addition the semiconductor switching elements 18-24 and the windings of the transformer unit 14 are excessively stressed and the efficiency of the voltage converter 10 is reduced.

In order to counteract these short circuits, the voltage converter 10 has a control device 38 which has an element 40 for generating a control of the switching unit 12, in this case of control signals for the switching elements 18-24, as well as an electric motor. ment 42 for generating a control of the rectifying elements 26, 28, here a time offset of the control signals for the rectifying elements 26, 28 with respect to the control signals for the formwork elements 18-24, has (Fig. 1, 3).

4 shows the time profile of the voltages 44a-d of the switching elements 18-24, which result from the activation by the element 40. The control signals generated by the element 40 cause switching of the switching elements 18-24 in the voltage zero crossing. In this case, the control signals for the switching elements 18-24 are selected such that a fixed time offset T _AB or T _CD between the switch-on and switch-off of the switching elements 18, 20 and 22, 24 result. The voltages 44a, b and 44c, d of the switching elements 18, 20 and 22, 24 are shifted in time according to each other.

A signal with information about the control signals for the switching elements 18-24 is transmitted to the element 42 for generating the time offset of the drive signals for the rectifier elements 26, 28, so that the element 42 generate such drive signals for the rectifier elements 26, 28 can be that the voltages 46a, b of the rectifying elements 26, 28 are offset by T _0n and T _off with respect to the voltages 44a-d of the switching elements 18-24 and the transformer unit 14, respectively.

The time offset T _0n and T _off is a fixed, predetermined value that is manually selected based on the circuit _{topology of} the voltage converter 10. The value of the time offset T _0n and T _off can also be determined from a voltage and current pattern of the components of the voltage converter 10 or from an input and output voltage V _H v and V _LV in an earlier operation of the voltage converter 10. FIG. 5 shows a further voltage converter 10 in the step-down position, which has no galvanic insulation, so that a switching unit 12 is connected directly to a rectification unit 16. A switching element 18 of the

Switching unit 12 and a rectifying element 26 of the rectifying unit 16 are formed as a MOSFET.

A control device 38 of the voltage converter 10 has an element 40 for generating a control of the switching element 18, as well as an element 42 for generating a control of the rectifying element 26. The elements 40, 42 work digitally based.

The control signals for the switching element 18 cause such a switching of the switching unit 12, that results in a voltage waveform 44 of the switching element 18 shown in FIG. 6. The element 42 generates for the rectification element 26 such a clock signal that a voltage curve 34 of the rectification element 26 is _displaced by a fixed time offset T _0n , T _off to the voltage curve 44 of the switching element 18. _During operation of the voltage converter 10, these time _offsets (dead times) T _0n , T _off are fixed values for switching the rectification element 26 on and off. Moreover, these values are T _0n , T _off for the switch-on and switch-off _{times of} the switching element 18 and the rectifying element 26 the same.

Alternatively, the element 42 can control the rectification element 26 in such a way that switching on and off of the switching element 18 and of the switching element 18 switched on and off by time-variable values T _0n , T _off

Rectifying element 28 takes place (FIG. 7). In the illustrated embodiment, T _0n and T _{off are} different in length. The time _offsets (dead times) T _0n and T _off can be determined _{depending on the} power, so that they are determined for example by an output current of the voltage converter 10, an input or output voltage of the voltage converter 10 or a duty cycle of the switching element 18 or the rectifying element 26.

The separate time-digital displacement of the control signals for the rectifying element 26 causes an intrinsic diode of the rectifying element 26 to participate only minimally in the rectification in the voltage converter 10.

Claims

claims

A control device for controlling at least one rectifying element (26, 28) of a voltage converter (10), wherein the voltage converter (10) has a switching unit (12) and a rectifying unit (16) with the at least one rectifying element (26, 28), wherein the control device (38) is designed to control the at least one rectifying element (26, 28) independently of the switching unit (12).

2. Control device according to claim 1, wherein the control device (38) is adapted to control the at least one rectifying element (26, 28) offset in time to the switching unit (12).

3. Control device according to claim 1 or 2, wherein a time offset (T _0n , T _off ) between a driving of the switching unit (12) and a driving of the at least one rectifying element (26, 28) is a time-fixed time offset.

4. _{Control device} according to claim 1 or 2, wherein a time offset (T _0n , T _off ) between a driving of the switching unit (12) and a driving of the at least one rectifying element (26, 28) a time-variable time offset depending on a characteristic of the Voltage converter (10) is.

5. Control device according to claim 4, wherein the characteristic variable from a group consisting of an input voltage (V _H v) of the voltage converter (10), an input current of the voltage converter (10), an output voltage (V _LV ) of the voltage converter (10), a Output current of the voltage converter (10) and a duty cycle of the at least one rectifying element (26, 28) is selected.

6. Control device according to one of claims 1 to 5, wherein the control device (38) comprises a member (40) for generating a control of the switching unit (12) and an element (42) for generating a control of the at least one rectifying element (26, 28). having.

7. Control device according to one of claims 1 to 6, wherein the rectification unit (16) has at least one further rectifying element (26, 28), wherein the control device (38) is adapted to the at least further rectifying element (26, 28) independently to be controlled by the switching unit (12).

8. Control device according to claim 7, wherein the control device (38) is adapted to control the at least one further rectifying element (26, 28) independently of the at least one rectifying element (26, 28).

9. vehicle, with a control device (38) according to one of claims 1 to 8 for controlling at least one

Rectifying element (26, 28) of a voltage converter (10) of the vehicle.

10. The vehicle of claim 9, wherein the vehicle is selected from the group consisting of an automobile, a passenger car, a truck, a bus, a train, an aircraft and a ship.

11. A method for controlling at least one rectifying element of a voltage converter, wherein the voltage converter has a switching unit and a rectifying unit with the at least one rectification element, wherein the at least one rectifying element (26, 28) is controlled independently of the switching unit (12).

A computer readable storage medium storing a program for controlling at least one rectifying element (26, 28) of a voltage converter (10) adapted to perform the method of claim 11 when executed by a processor.

A program element for controlling at least one rectifying element (26, 28) of a voltage converter (10) adapted to perform the method of claim 11 when executed by a processor.