CN104718099B

CN104718099B - Control circuit for at least one contactor and method for operating at least one contactor

Info

Publication number: CN104718099B
Application number: CN201380054201.3A
Authority: CN
Inventors: C·齐瓦诺波洛斯; D·哈森科普
Original assignee: Robert Bosch GmbH; Samsung SDI Co Ltd
Current assignee: Robert Bosch GmbH; Samsung SDI Co Ltd
Priority date: 2012-10-18
Filing date: 2013-09-23
Publication date: 2020-09-01
Anticipated expiration: 2033-09-23
Also published as: CN104718099A; DE102012218988A1; WO2014060183A1

Abstract

The invention relates to a control circuit (30) for at least one contactor, comprising a first and a second connection (11, 12). The control circuit (30) further comprises a first and a second output (15, 16), via which the control circuit (30) can be connected to a first and a second connection of a control coil for the contactor. The control circuit (30) further comprises a voltage holding unit (10) which is connected to the first output (15) and is designed to provide a holding voltage for the control coil at the first output (15). According to the invention, the electrical connection (8) has a current regulation circuit (5) which is provided to regulate the current through the electrical connection (8) to a predetermined value. A method for operating at least one contactor is also provided.

Description

Control circuit for at least one contactor and method for operating at least one contactor

Technical Field

The invention relates to a control circuit for at least one contactor, comprising a voltage holding unit and a current regulation circuit, by means of which the current through the control coil of the contactor can be precisely regulated to a target value.

Background

It is clear that in the future, not only in stationary applications, but also for example in hybrid and electric vehicles, more battery systems will be used, for which very high demands are made with regard to reliability. The reason is that failure of the storage battery can cause a problem related to safety. In order to provide the power desired for the respective application, a large number of battery cells are usually connected in series, so that a high battery output voltage is obtained, which battery permanently contacts the respective supply connection of the device supplied by the battery without suitable measures and represents a danger for maintenance personnel or users. For this reason, contactors are usually provided to enable the electrical decoupling of the batteries. In motor vehicles with an electric control motor, contacts are attached to both the positive pole and the negative pole of the battery, which provide a high voltage for the battery and also have to be able to reliably disconnect the battery in the event of a short-circuit current of more than 1000A.

The switching on and off of the contactor is usually effected by means of electronic terminals or by means of a control circuit which supplies a current to a control coil of the contactor. Here, the control power is not so small as to be ignored. A much higher control current is required during the switching process in order to reliably pull the contactor into contact than in the closed state in order to subsequently maintain contact. For this reason, the control of the contactor is usually divided into two modes, a pull-in mode and a hold mode (or also a pull-in phase or a hold phase). It is specific to each mode that the magnitude of the control current is larger in the pull-in mode than in the hold mode. Referred to herein as a pull-in level and a hold level. Wherein the pull-in mode is only necessary for making (closing) the connector and has a relatively short duration. The contactor is in a power saving hold mode for a major part of the operating time. Therefore, the control circuit for controlling the contactor should be able to display two operating modes.

DE 102010041018 discloses a device for controlling a contactor, which comprises a current holding unit, which is designed to output a holding current for a control coil of the contactor to an output of its output side. With the device disclosed in DE 102010041018 a1, the contactor can be controlled in an advantageous manner during the pull-in phase and also during the hold phase at different voltage levels with a constant voltage.

However, the coil resistance of the relevant components, in particular the control coil of the contactor, in the device disclosed in DE 102010041018 a1, for example, has a temperature dependence and a manufacturing-related scattering of its component parameters. In addition, the holding voltage generated by the holding current unit is regulated to a value determined for the production time.

The relevant components (in particular those within the voltage holding circuit of the control circuit) must therefore be designed in such a way that the necessary holding current can be supplied even in the event of an excessively high temperature of the holding current unit. However, since the electrical conductivity of the components and thus the current flowing through the same, for example, the control coil of the contactor fluctuates as a function of temperature, it is necessary to dimension these components to be greater than would otherwise be necessary for the desired current. For example, the relevant components in the holding circuit of the device disclosed in DE 102010041018 a1 must therefore be dimensioned to be higher by 66%, which considerably increases the construction space required for these components and also the costs.

Disclosure of Invention

According to the invention, a control circuit for at least one contactor is proposed, which comprises a first and a second connection terminal, by means of which the control circuit can be connected to a plurality of poles of an energy store. Furthermore, the control circuit comprises at least one first output and at least one second output, via which the control circuit can be connected to a first and a second connection of a control coil for the contactor. The at least one second output is electrically connected to the second connection. The control circuit also comprises a voltage holding unit which is connected to the at least one first output and is designed to provide a holding voltage for the control coil at the at least one first output. According to the invention, the electrical connection has a current regulation circuit which is provided to regulate the current through the electrical connection to a predetermined value.

This is possible by means of the control circuit, which, with a constant holding voltage during the holding phase, regulates the current precisely for each temperature by means of the control coil of the contactor. The components of the control circuit, which are provided in the holding voltage circuit, for example, then do not have to be large, since a temperature-dependent increase or decrease of the current in the holding voltage circuit can be acted on by the current regulation circuit. Thereby enabling cost and manufacturing space savings.

In a preferred embodiment, the current regulation circuit comprises a transistor arranged in the electrical connection, wherein the transistor has a control electrode and is provided to be linearly controlled and to operate as a current source. By means of a plurality of transistors, a plurality of signals can be switched and amplified without having to carry out mechanical movements again. The plurality of transistors operate near an operating voltage. Which has small losses, very little heat generation and very small dimensions. Furthermore, transistors can be used well as current sources or for regulating the current, since the resistance of the switching line (Schaltstrecke) of the transistor is accurately adjustable.

In a preferred refinement of this embodiment, the transistor is implemented as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) or as a bipolar transistor. MOSFETs are cost-effective and very compact, i.e. can be realized with a high integration density. In addition, MOSFETs have fast switching times and stable amplification and response times. While bipolar transistors have a high voltage stability and equally a high switching speed. In addition, its conduction loss is linearly proportional to the current flowing therethrough and the collector-emitter saturation voltage.

Preferably, the current regulation circuit has a current measurement unit connected to the electrical connection. This makes it possible to measure the current in the electrical connection and the current through the control coil very precisely and to overcome deviations of the current from its nominal value.

In a preferred refinement of this embodiment, the current measuring unit is embodied as a shunt resistor. The circuit resistor or shunt is very cost-effective compared to other current measuring units or current sensors and is also capable of measuring currents very accurately.

In this embodiment or in a preferred refinement of any of the preceding embodiments, the current regulation circuit has a regulation unit which is connected to the current measurement unit and to the control electrode of the transistor and is provided for linear control of the transistor via the control electrode as a function of the current measured by the current measurement unit.

Preferably, the regulating unit is implemented as a feedback amplifier circuit having an output and two inputs, wherein the output of the feedback amplifier circuit is connected to the control electrode of the transistor, while one input of the feedback amplifier circuit is connected to the current measuring unit and the other input of the feedback amplifier circuit is connected to a constant potential.

Preferably, an input terminal of the feedback amplification circuit connected to a constant potential has a reference voltage source.

By means of this feedback amplifier circuit, the current measuring unit is connected to the control electrode of the transistor and can overcome the deviation of the current from the setpoint value directly by a change in the resistance of the switching line of the transistor. The current measured by the current measuring unit is not necessarily analyzed and transmitted first at great expense.

Preferably, the feedback amplification circuit is implemented as an operational amplifier. The operational amplifier is short-circuit stable, does not require frequency compensation, has a very large input voltage range, and absorbs little power.

In a preferred embodiment, the feedback amplifier circuit is implemented as an electronic circuit with discrete components. By the construction of discrete devices, cost advantages are obtained by the operational amplifier relative to the implementation of the feedback amplification circuit.

Preferably, the voltage holding unit is implemented as a switching converter. The switching converter is energy-saving and, due to its active current regulation, it is relatively insensitive to current or parameter fluctuations.

Furthermore, a method for operating at least one contactor is provided, comprising at least one control coil for controlling the at least one contactor and a voltage holding unit, which is connected to the at least one control coil and is designed to cause a current through the at least one control coil by means of a holding voltage generated at an output of the voltage holding unit. Furthermore, the method for operating at least one contactor comprises a current regulation circuit which is electrically conductively connected to the control coil and is designed to regulate the current through the at least one control coil to a predetermined value, wherein the method comprises the following method steps: a pull-in current flowing through the at least one control coil is provided by the voltage holding unit. A holding current flowing through the at least one control coil is provided by the voltage holding unit. The amount of current flowing through the at least one control coil is measured. Adjusting, by the current adjustment circuit, the current flowing through the at least one control coil to a predetermined value according to an amount of current flowing through the at least one control coil.

In a preferred refinement of the method for operating at least one contactor, the current regulation circuit further comprises a transistor, which is electrically conductively connected to the at least one control coil, and wherein, in the step of regulating the current through the at least one control coil to a predetermined value, the regulation of the current is effected by the current regulation circuit by linear control of the transistor.

Preferred refinements of the invention are given in the subclaims and set forth in the description.

Drawings

Various embodiments of the invention are further illustrated in the figures and the following description. Wherein:

FIG. 1 illustrates a prior art control circuit;

FIG. 2 illustrates an embodiment of a control circuit according to the present invention; and

fig. 3 shows a special embodiment of a control circuit according to the invention for controlling two contactors.

Detailed Description

A prior art control circuit 30 is shown in fig. 1. The control circuit 30 for controlling the contactor is connected via a first and a

second connection

11, 12 to a voltage source 60, only the control coil 50 of the contact being shown here, the voltage source 60 supplying the control circuit 30, but also supplying the current controlled by the control circuit 30 for controlling the contactor. The control coils 50 of the contactors are connected to the control circuit 30 via a first and a

second output

15, 16. The control circuit 30 has first and second switches 41, 42 connected between respective poles of a voltage source 60 and respective poles of a control coil 50. If both switches 41, 42 are closed at the same time, the control coil 50 is directly connected to the voltage source 60 and begins to flow a maximum current which is sufficiently large to enable the contactor to pull in, so that the contactor goes into a conducting state.

Furthermore, the control circuit 30 has a voltage holding unit 10, the voltage holding unit 10 also being supplied by the voltage source 60. The voltage holding unit 10 provides a holding voltage which is used in a holding phase following the pull-in phase to keep the contactor closed. Since here, unlike the mass inertia of the motor contactor that needs to be overcome during the pull-in phase, a smaller current is sufficient to keep the contactor in the closed state, power can advantageously be saved. In the holding phase, the first switch 41 is therefore opened again (and the voltage holding unit 10 is activated if necessary), so that the control coil 50 is only flowed through by the holding current. The holding current flows through a diode 45, which diode 45 is connected between the voltage holding unit 10 and the control coil 50 and has the function of blocking the current flow in the output of the voltage holding unit 10.

In addition, a freewheeling diode 46 is provided in fig. 1, which provides a freewheeling current path for the current flowing in the control coil 50 when the holding current is switched off. The disengagement phase begins by the second switch 42 also being opened and, if necessary, additionally deactivating the voltage holding unit 10. Since this control coil 50, due to its inductance, blocks the change in the current flowing through it, it also generates a current flow after its disconnection from the supply voltage, which current flow then switches on the freewheeling diode 46 and the diode 45 due to the series circuit. Since the second connection of the control coil 50 must conduct current, a correspondingly high negative voltage is generated here, which results in the zener diode serving as terminal voltage element 47 being broken down. The current in the control coil 50 is rapidly reduced so that the magnetic field of the control coil 50 is also reduced and the corresponding contactors are disengaged, whereby these contactors are opened.

The first switch 41, the second switch 42 and, if necessary, the holding voltage source 10 are controlled by the control unit 35.

Fig. 2 shows an embodiment of the control circuit 30 according to the invention. The control circuit 30 according to the invention can be connected to a plurality of poles of an energy store, for example, a battery or a battery system, via the first and

second connection

11, 12. The control circuit 30 according to the invention is connected to the two connections or poles of the control coil via the first and

second output

15, 16. In other words, the output 15 of the control circuit 30 can be connected to a first end of the control coil of the contactor, and the second output 16 of the control circuit 30 can be connected to a second end of the control coil of the contactor. The second output 16 is electrically conductively connected to the second connection 12 via the electrical connection 8. Furthermore, the control circuit 30 comprises a voltage holding unit 10, which is optionally connected on the input side to the first connection 11 of the control circuit 30 and on the output side to the first output 15 of the control circuit 30. Furthermore, the voltage holding unit 10 is provided for supplying or supplying a holding voltage for controlling the coil at a first output 15 of the control circuit 30. In the control circuit 30 according to the invention, the voltage holding unit 10 is not necessarily connected to one of the

connections

11, 12. It is also possible to implement a plurality of control circuits 30 according to the invention, wherein the control circuits according to the invention are connected neither to the first connection nor to the

second connection

11, 12 of the control circuit 30.

According to the invention, the electrical connection 8 between the second output 16 and the second connection 12 has a current regulation circuit 5 which is provided to regulate the current through the electrical connection 8 to a predetermined value. In other words, it is possible by means of the current regulating circuit 5 to influence or vary the current by means of a control coil connected to the control circuit 30 and to regulate this current to a defined value without the holding voltage set by the voltage holding unit 10 having to be varied for this purpose. The change or setting of the current through the control coil or through the electrical connection 8 may not require an influence or action on the voltage holding unit 10,

fig. 3 shows a special embodiment of a control circuit 30 according to the invention for controlling two contactors. The control circuit 30 of this embodiment in fig. 3 corresponds here largely to that shown in fig. 1. Via the first and

second connection

11, 12, the control circuit 30 is connected to an energy store 60, which in this exemplary embodiment is embodied purely as a low-voltage battery. In this embodiment, the second pole of the energy store 60 is additionally connected purely by way of example to ground. The exemplary embodiment of the control circuit 30 according to the invention shown in fig. 3 furthermore has a first output 15 and two second outputs 16. The first output is connected to the first connection of each contact or to the first ends of two control coils 50, which are embodied identically in this exemplary embodiment. The second connection of one contactor or the second end of the control coil 50 is connected to one of the second plurality of output terminals 16 of the control circuit 30, while the second connection of the other contactor or the second end of the other control coil 50 is connected to another of the second plurality of output terminals 16 of the control circuit 30. The two second outputs 16 of the control circuit 30 are each connected to a second connection 12 of the control circuit 30 via an electrical connection 8. In other words, the second output 16 of the control circuit 30 is connected via the electrical connection 8 to the second connection 12 of the control circuit 30, while the further second output 16 of the control circuit 30 is connected via the further electrical connection 8 to the second connection 12 of the control circuit 30. The control circuit 30 also has a voltage holding unit 10, which is implemented as described in fig. 1 and is connected in the control circuit 30. In other words, the voltage holding unit 10 has two inputs, via which the voltage holding unit 10 is connected in this exemplary embodiment to the first and

second connection

11, 12 and via which it is connected to the two poles of the energy store 60. Furthermore, the output of the voltage holding unit 10 is connected to the first output 15 of the control circuit 30, as in fig. 1, via an optional diode 45. The electrical connection between the diode 45 and the control circuit 30, between the voltage holding unit 10 and its first output 15, is connected with an optional freewheeling diode 46, as in fig. 1. The cathode of freewheeling diode 46 is connected to the electrical connection between voltage holding unit 10 and its first output 15, while the anode of this freewheeling diode is connected to a local ground of control circuit 30. In the exemplary embodiment of fig. 3, the first connection 11 of the control circuit 30 is connected via an optional switching device 41 to the first output 15 of the control circuit 30 and thus to the first connection or first end of the control coil 50. The control coil 50 is also directly connected to the poles of the energy store 60 via an optional switching device 41. By closing the switching device 41, a maximum current flows through the control coil 50 at the electrical connection 8 which is conducted between the second output terminal 16 and the connection terminal 12, so that the contactor is engaged, thereby switching the contactor into the conductive state. Furthermore, this embodiment of the control circuit 30 according to the invention has an optional control unit 35, by means of which not only the optional switching device 41 but also the voltage holding unit 10 is controllable.

According to the invention, the plurality of electrical connections 8 between the second output 16 and the connection 12 of the control circuit 30 each have a current regulation circuit 5, which is provided to measure the current through the respective electrical connection 8 and to set or regulate it to a predetermined value. For purposes of observation, the two current regulating circuits 5 of this embodiment in fig. 3 are different and implemented in accordance with the present invention. The control circuit 30 according to the invention can also be implemented in such a way that a plurality of current regulation circuits 5 are identically implemented. Common to both current regulation circuits 5 is that they both have a transistor 4. In this case, a plurality of transistors 4 with switching lines are located in each of the electrical connections 8. Each of the plurality of transistors 4 has a control electrode. Furthermore, the current control circuits 5 each have a current measuring unit 3 connected to the respective electrical connection 8, which is provided in each case for measuring the current flowing through the respective electrical connection 8. When the current measuring units 3 in the two current regulation circuits 5 are embodied as shunt resistors, the transistors 4 in the current regulation circuits 5 are embodied purely exemplarily as MOSFETs, while the transistors 4 of the further current regulation units 5 are embodied purely exemplarily as bipolar diodes. The transistor 4 of the current regulation unit 5 is provided to be controlled linearly and to operate as a current source. In other words, transistor 4 is provided to operate in the linear region of its characteristic curve, so that the resistance with the corresponding switching line can be variably adjusted. The implementation of the transistor as a MOSFET or a bipolar diode, or of the current measuring unit 3 as a shunt resistor, is purely exemplary selectable in this embodiment. The control circuit 30 according to the invention can also be implemented in such a way that the transistor 4 or the current measuring unit 3 is implemented additionally.

In this exemplary embodiment, each of the plurality of current regulation units 5 also has a regulation unit 2, which is connected to the current measurement unit 3 and to the control electrodes of the transistors 4 within the respective current regulation circuit 5 and is provided for linearly controlling the respective transistor by its control electrode as a function of the current measured by the respective current measurement unit 3 or for operating it as a current source. In this exemplary embodiment, a plurality of control units 2 are each connected to a measuring connection of a shunt resistor. In other words, the plurality of regulating units 2 are able to apply control signals to the control electrodes of the plurality of transistors 4, respectively, depending on the current measured by the respective current measuring unit 3, the control signals corresponding to the magnitude of the current through the respective electrical connection 8. The resistance of the switching line of the transistor 4 can therefore be reduced or increased by the control of the regulating unit 2 depending on the current through the respective electrical connection 8. The current through the electrical connection 8 and thus the current through the control coil 50 connected to the electrical connection 8 via the second connection 16 is thereby regulated or regulated.

In the embodiment of fig. 3, two regulating units 2 are purely exemplarily implemented as feedback amplifying circuits. In this case, the feedback amplifier circuit is embodied purely by way of example as an electronic circuit in the current regulation circuit 5 with MOSFETs, which has discrete components. The electronic circuit is also comprised of individual, individual and discrete components or assemblies.

The electronic circuit of the current regulating circuit 5 is connected to the gate of the MOSFET. Alternatively, in the case of a MOSFET to implement the transistor 4, a diode can be connected in parallel with the switching line of the MOSFET, the cathode of which, as in this exemplary embodiment, can be connected purely exemplarily to the respective second output 15, and the anode of which is connected to the second connection 12. In a further current regulation circuit 5 with a bipolar transistor, the feedback amplifier circuit is embodied purely by way of example as an operational amplifier, the output of which is connected to the base of the bipolar transistor, while the inverting input of the operational amplifier is connected purely by way of example to the measuring connection of the shunt resistor and the non-inverting input is connected to a constant potential, in this embodiment locally. In addition, the non-inverting input of the operational amplifier has in this exemplary embodiment a reference voltage source, by means of which a reference potential for the regulation current can be transmitted to the feedback amplifier circuit.

Whether implemented as a plurality of regulating units 2 or as a feedback amplifying circuit, is a purely exemplary choice in this embodiment. The plurality of control circuits 30 according to the invention can also be realized with a current regulation circuit 5 having a plurality of regulation units 2 implemented in other ways. The regulation unit 2 embodied as a feedback amplification circuit can also be implemented in the control circuit 30 according to the invention in a manner different from that shown in the exemplary embodiment.

Furthermore, it is also possible to realize a plurality of control circuits 30 according to the invention, which are provided for controlling more than two contactors, i.e. are connected with more than two control coils 50. Furthermore, the associated plurality of transistors 4 in the current regulation circuit 5 of the control circuit 30 according to the invention can be provided for switching operation or switching regulation, i.e. for switching operation, in addition to linear operation. By means of this embodiment, the plurality of transistors 4 can be completely switched on, i.e. conductively connected or blocked, for example in the pull-in phase or pull-out phase of the contactor.

Claims

1. A control circuit (30) for at least one contactor, comprising:

-a first and a second connection (11, 12) by means of which the control circuit (30) can be connected to a plurality of poles of the energy storage;

-at least one first and one second output (15, 16), via which the control circuit (30) can be connected to a first and a second connection of a control coil for a contactor, wherein the at least one second output (16) is connected to the second connection (12) via an electrical connection (8);

-a voltage holding unit (10) connected to the at least one first output (15) and configured to provide a holding voltage for the control coil at the at least one first output (15);

it is characterized in that the preparation method is characterized in that,

the electrical connection (8) has a current regulation circuit (5) comprising a transistor (4), wherein the transistor (4) is provided for operating in the linear region of its characteristic curve in order to regulate the resistance of the switching line of the transistor (4) and to regulate the current through the electrical connection (8) to a predetermined value.

2. The control circuit (30) as claimed in claim 1, wherein the transistor (4) is arranged in the electrical connection (8), wherein the transistor (4) has a control electrode and is arranged to be controlled linearly and to operate as a current source.

3. The control circuit (30) according to claim 2, wherein the transistor (4) is implemented as a metal oxide semiconductor field effect transistor, MOSFET, or a bipolar transistor.

4. The control circuit (30) according to any one of the preceding claims, wherein the current regulating circuit (5) has a current measuring unit (3) connected with the electrical connection (8).

5. The control circuit (30) as claimed in claim 4, wherein the current measuring unit (3) is implemented as a shunt resistor.

6. The control circuit (30) as claimed in claim 2, wherein the current regulating circuit (5) has a regulating unit (2) which is connected with the current measuring unit (3) and the control electrode of the transistor (4) and is provided for linearly controlling the transistor (4) as a function of the current measured by the current measuring unit (3) via the control electrode of the transistor.

7. The control circuit (30) as claimed in claim 6, wherein the regulating unit (2) is implemented as a feedback amplification circuit having an output and two inputs, wherein the output of the feedback amplification circuit is connected to the control electrode of the transistor (4) and one input of the feedback amplification circuit is connected to the current measuring unit (3) and the other input of the feedback amplification circuit is connected to a constant potential.

8. The control circuit (30) of claim 7, wherein the feedback amplification circuit is implemented as an operational amplifier.

9. The control circuit (30) of claim 7, wherein the feedback amplification circuit is implemented as an electronic circuit with discrete devices.

10. The control circuit (30) according to any of claims 1-3, wherein the voltage holding unit (10) is implemented as a switching converter.

11. A method for operation of at least one contactor, comprising:

-at least one control coil for controlling at least one contactor;

-a voltage holding unit (10) connected to at least one control coil and configured to induce a current through the at least one control coil by means of a holding voltage generated at an output of the voltage holding unit;

-a current regulating circuit (5) which is electrically conductively connected to the control coil and is designed to regulate the current through the at least one control coil to a predetermined value, wherein the method comprises the following method steps:

-providing a pull-in current (S1) through the at least one control coil by the voltage holding unit (10);

-providing a holding current (S2) through the at least one control coil by the voltage holding unit (10);

-measuring (S3) an amount of current flowing through the at least one control coil;

-adjusting (S4), by the current adjustment circuit (5), the current flowing through the at least one control coil to a predetermined value depending on the amount of current flowing through the at least one control coil,

wherein the current regulating circuit (5) comprises a transistor (4) which is electrically conductively connected to the at least one control coil and

wherein in the step of adjusting (S4) the current through the at least one control coil to a predetermined value, the transistor (4) operates in the linear region of its characteristic curve to adjust the resistance of the switching line of the transistor (4) and to adjust the current through the electrical connection (8) to the predetermined value.