DE102007035825A1 - Electrical device with a semiconductor device - Google Patents

Abstract

The invention relates to an electrical device 1 with a power semiconductor 3 and means for protecting the power semiconductor 3 from thermal overload. The electrical device 1 comprises a measuring device 4 for detecting the current i <SUB> LH </ SUB> flowing through the power semiconductor 3 and a monitoring device 5 which supplies the current i <SUB> LH </ SUB> flowing through the power semiconductor 3 and in which the loss energy E <SUB> loss </ SUB> of the power semiconductor 3 is determined based on a model of the power semiconductor 3 and the supplied current i <SUB> LH </ SUB>. In dependence on the determined loss energy E <SUB> loss </ SUB>, the current i <SUB> LH </ SUB> is controlled by the power semiconductor 3.

Description

State of the art

The The invention relates to an electrical device with a semiconductor device according to the preamble of claim 1. Furthermore, the invention relates a method for the control of an electrical device according to the preamble of claim 2. In particular, it may be This is an electric induction machine, which is used in hybrid and Electric vehicles can be used as a prime mover. For The operation of such a rotary field machine are pulse inverters used. A pulse inverter includes semiconductor components in the form of power semiconductors, such as MOSFET transistors or IGBT (Insulated Gate Bipolar Transistor - Bipolar Transistor with insulated gate electrode). To this power semiconductors as possible to make good use of, they are as close as possible their power limit operated. The resulting heat loss heats the power semiconductors and must be dissipated because the power semiconductors are not above their limit temperature can be operated, otherwise they will be destroyed.

It is known for the dissipation of heat loss Use heat sink and so-called heat pipes. These are additional, cost-causing Components that also have a comparatively large amount of space claim and therefore not in confined spaces without can be used further.

Out DE 102 27 008 A1 Furthermore, a cooling device for semiconductor modules with a cooling rail for receiving at least one, in particular actively cooled semiconductor module is known, with at least one first channel in the radiator rail for passing a particular liquid cooling medium and at least one second channel in the radiator rail for supplying and / or recycling the cooling medium to / from the semiconductor module.

It is also known, the temperature of a power semiconductor to monitor and load the power semiconductor reduce when the temperature exceeds a predetermined threshold. The load can be reduced by the Power semiconductors flowing current is reduced. These Solution requires a temperature sensor that either directly on the power semiconductor itself or in the immediate vicinity Must be mounted near. When the power semiconductor is used in a high voltage environment, the output signal of the Temperature sensor also via a potential separation be passed to an evaluation, what an additional Effort required.

Disclosure of the invention

Technical task

Of the Invention is based on the object at a device of generic type the protection of a power semiconductor to improve.

Technical solution

outgoing from an electrical device of the generic type This object is achieved by the features mentioned in claim 1 solved. An improvement in the protection of a power semiconductor results according to the invention in particular by that the electrical device is a measuring device for the detection of the current flowing through the power semiconductor Electricity includes that the electrical device further comprises a monitoring device which is the one flowing through the power semiconductor Power is supplied and in the on the basis of a power semiconductor simulating Model and the current supplied the loss energy of the Power semiconductor is determined and that depending from the determined energy loss of the current through the power semiconductor is controlled.

One inventive method for the control an electrical device with a power semiconductor and Means for protecting the power semiconductor from thermal overload is characterized in that by the power semiconductor flowing current is detected, that is a reading of that Power supplied to a monitoring device is, in which on the basis of a simulating the power semiconductor Model and the supplied reading of the current the loss energy of the power semiconductor is determined, and that depending from the determined energy loss of the current through the power semiconductor is controlled.

Especially advantageous for the power semiconductor in this case Value for the permanently allowed current set, and the energy lost in the monitoring device a relationship explained in more detail below, when the current flowing through the power semiconductor is greater than the permanently allowed Electricity.

Furthermore, a limit value is advantageously predetermined for the energy loss, exceeding which the current flowing through the power semiconductor is controlled to the current that is permissible as a permanent current. When the current flowing through the power semiconductor is smaller than the permissible current, the loss energy becomes advantageous determined according to a second, explained in more detail below relationship.

Advantageous a limit value for the energy loss is also defined when it falls below the current flowing through the power semiconductor current to one above the permanently permissible current lying Power is controlled.

Advantageous be the inventive device and the inventive method for protection a pulse inverter of an electric or hybrid vehicle used.

there the monitoring device can advantageously locally remote from the power semiconductor to be protected be, since its only a reading of the power semiconductor must be supplied to flowing electricity. any Restrictions on the installation space in the immediate Neighborhood of the power semiconductor must therefore not be taken into account.

Especially Advantageously, the monitoring device can also be used as a software module a control program for an electrical device be realized with a power semiconductor.

Further Benefits result from the description, the drawing and the Dependent claims.

Brief description of the drawings

embodiments The invention will be described in more detail below with reference to the drawing explained. Showing:

1 a block diagram of an electrical device with a power semiconductor;

2 a flowchart.

Embodiments of the invention

Embodiments of the invention are explained in more detail below with reference to the drawing. 1 shows a block diagram of an electrical device 1 with at least one power semiconductor 3 , The power semiconductor 3 is with a power source 2 connected to the power semiconductor 3 powered. Next is the power semiconductor 3 with a measuring device 4 connected by the power semiconductor 3 flowing current i _LH detected. The measuring device 4 is with a monitoring device 5 connected, in turn, the output side with the power source 2 connected is. In the monitoring device 5 is a model of the power semiconductor 3 deposited. Based on this model and that of the measuring device 4 detected current through the power semiconductor 3 determines the monitoring device 5 in the power semiconductor 3 resulting power loss E _Loss . Depending on the determined power loss controls the monitoring device 5 via the power source 2 the power semiconductor 3 supplied power.

This method will be described below with reference to in 2 illustrated flowchart explained further. step 20 is assumed as a starting point. In the step 21 becomes the power semiconductor 3 energized, causing it, as a result of the resulting heat loss, heated. In the step 22 is using the measuring device 4 by the power semiconductor 3 flowing current is detected. In step 23 it is checked if the by the power semiconductors 3 flowing current is smaller, equal to or greater than a permanently permissible current value i _{LH_Dauer} . Is that the power semiconductors 3 supplied current i _LH greater than the permanent allowable current i _{LH_Duration} , this reading of the current in the step 25 the monitoring device 5 supplied on the basis of the stored in her model of the power semiconductor 3 and the measured value of the current supplied to it in the power semiconductor 3 resulting power loss E _Loss calculated. In the step 28 it is checked whether the power loss exceeds a predetermined limit. If this is the case, in the step 30 , via the appropriate control of the power source 2 , the power semiconductor 3 supplied current reduced to the permanently permissible current value i _{LH_Dauer} .

When in the step 23 turns out that by the power semiconductor 3 flowing current is less than the permanent allowable current, this reading is in the step 24 the monitoring device 5 fed on the basis of the stored in her model of the power semiconductor 3 and the measured value of the current supplied to it in the power semiconductor 3 resulting power loss E _Loss calculated. In the step 26 It checks if the monitoring device 5 determined power loss E _{loss takes} the value zero. If this is the case, in the step 29 , via the appropriate control of the power source 2 , the power semiconductor 3 supplied current to a permanently permissible current value i _{LH_Dauer} exceeding value i _{LH_Grenz} increased.

Will in the step 23 found that the measured current i _LH through the power semiconductor 3 is essentially as large as the permanent allowable current i _{LH_Duration} , then becomes the step 27 reconciled. This means that in the monitoring device 5 no contribution to the loss energy is calculated.

In summary, in the We significantly differentiate the following situations:

Case A:

The current in the power semiconductor i _LH is greater than the permanently allowed current i _{LH_Dauer} .

Now the energy of loss is calculated according to the following relation: e loss = E Verlust_Alt + ∫P loss (i LH - i LH_Dauer ) dt (1)

If now E _loss > E _{loss_limit} then the current flowing through the power _{semiconductor is} reduced to the permanently allowable current i _{LH_Duration} .

Case B:

The current i _LH flowing through the power semiconductor is exactly the same as the permanently permissible current i _{LH_Dauer} . In this case is not with an overload of the power semiconductor 3 to count.

Case C:

The by the power semiconductor 3 flowing current i _LH is less than the permanently permissible current I _{LH_Dauer} . Now the loss energy is calculated according to the following relationship: e loss = E Verlust_Alt - ∫P loss (i LH - i LH_Dauer ) dt (2)

If E _loss = 0, then the maximum possible current i _{LH is increased} to the short-term possible limit current i _{LH_Grenz} . The calculation of the loss energy is stopped.

i_LH:

Strom durch den Leistungshalbleiter;

i_{LH_Dauer}:

Strom durch den Leistungshalbleiter, der dauerhaft fließen kann ohne den Leistungshalbleiter zu beschädigen;

i_{LH_Grenz}:

Grenzstrom durch den Leistungshalbleiter, der kurzzeitig fließen kann ohne den Leistungshalbleiter zu beschädigen;

E_Verlust:

Verlustenergie;

E_{Verlust_Alt}:

im jeweils letzten Zyklus berechnete Verlustenergie;

E_{Verlust_Grenz}:

Grenze der Verlustenergie, die nicht überschritten werden soll;

P_Verlust(i_LH – i_{LH_Dauer}):

Verlustleistung, die abhängig ist von der Differenz des Stroms durch den Leistungshalbleiter und dem dauerhaft möglichen Strom durch den Leistungshalbleiter.

In the aforementioned relationships (1) and (2),

i _LH :

Current through the power semiconductor;

i _{LH_Duration} :

Current through the power semiconductor that can flow permanently without damaging the power semiconductor;

i _{LH_Grenz} :

Limiting current through the power semiconductor, which can flow for a short time without damaging the power semiconductor;

E _loss :

Loss of energy;

E _{loss_old} :

Loss energy calculated in the last cycle;

E _{loss_limit} :

Limit of the loss energy that should not be exceeded;

P _loss (i _LH - i _{LH_Duration} ):

Power loss, which is dependent on the difference of the current through the power semiconductor and the permanently possible current through the power semiconductor.

Especially advantageous are the electrical device and the method used for their control in conjunction with a pulse-controlled inverter, the Part of the energy supply of an electric or hybrid vehicle is.

Particularly advantageous is the monitoring device 5 realized as a software module of a control program for the control of the electrical device.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 10227008 A1 [0003]

Claims (10)

Electrical device ( 1 ) with a power semiconductor ( 3 ) and means for protecting the power semiconductor ( 3 ) against thermal overload, characterized in that the electrical device ( 1 ) An institution ( 4 ) for the detection by the power semiconductor ( 3 ) flowing current (i _LH ) comprises that the electrical device ( 1 ) a monitoring device ( 5 ) Which of the power semiconductors ( 3 ) flowing current (i _LH ) is supplied and in the on the basis of a power semiconductor ( 3 ) model and the current supplied the loss energy (E _loss ) of the power semiconductor ( 3 ) is determined and that in dependence on the determined energy loss (E _loss ) of the current (i _LH ) by the power semiconductor ( 3 ) is controlled. Method for controlling an electrical device ( 1 ) with a power semiconductor ( 3 ) and means for protecting the power semiconductor ( 3 ) before thermal overload, characterized in that the by the power semiconductor ( 3 ) current (i _LH ) is detected, that a measured value of this current (i _LH ) of a monitoring device ( 5 ) is supplied, in which on the basis of a power semiconductor ( 3 ) model and the supplied measured value of the current (i _LH ) the loss energy (E _loss ) of the power semiconductor ( 3 ), and that in dependence on the determined energy loss (E _loss ) of the current (i _LH ) by the power semiconductor ( 3 ) is controlled. Method according to one of the preceding claims, characterized in that for the power semiconductor ( 3 ) a value for the permanently permissible current (i _{LH_Dauer} ) is set, and that the loss _energy (E _loss ) in the monitoring _device ( 5 ) is determined according to the following relationship when the power semiconductor ( 3 ) flowing current (i _LH ) is greater than the permanently permissible current: e loss = E Verlust_Alt + ∫P loss (i LH - i LH_Dauer ) Dt, with i _LH : current through the power semiconductor; i _{LH_Duration} : current through the power semiconductor, which can flow permanently without damaging the power semiconductor; i _{LH_Grenz} : _limiting current through the power semiconductor, which can flow for a short time without damaging the power semiconductor; E _loss : loss energy; E _{Loss_Old} : _{Loss energy} calculated in the last cycle; E _{loss_limit} : limit of the loss _energy that should not be exceeded; P _loss (i _LH - i _{LH_Duration} ): _Power loss, which depends on the difference of the current through the power semiconductor and the permanently possible current through the power semiconductor. Method according to one of the preceding claims, characterized in that a limit value (E _{loss_limit} ) is specified for the _energy loss (E _loss ) and that, when the limit value (E _{loss_limit} ) is exceeded, the value determined by the power semiconductor (E 3 ) flowing current (i _LH ) is controlled as the permanently permissible current (i _{LH_Dauer} ). Method according to one of the preceding claims, characterized in that for the power semiconductor ( 3 ) a value for the permanently permissible current (i _{LH_Dauer} ) is set, and that the loss _energy (E _loss ) in the monitoring _device ( 5 ) is determined according to the following relationship when the power semiconductor ( 3 ) flowing current (i _LH ) is smaller than the permanently permissible current (i _LH ): e loss = E Verlust_Alt - ∫P loss (i LH - i LH_Dauer ) Dt, with i _LH : current through the power semiconductor; i _{LH_Duration} : current through the power semiconductor, which can flow permanently without damaging the power semiconductor; i _{LH_Grenz} : _limiting current through the power semiconductor, which can flow for a short time without damaging the power semiconductor; E _loss : loss energy; E _{Loss_Old} : _{Loss energy} calculated in the last cycle; E _{loss_limit} : limit of the loss _energy that should not be exceeded; P _loss (i _LH - i _{LH_Duration} ): _Power loss, which depends on the difference of the current through the power semiconductor and the permanently possible current through the power semiconductor. Method according to one of the preceding claims, characterized in that for the loss _energy (E _loss ) a limit value (E _{loss_limit} ) is specified and that _{falls below} the limit value (E _{Verlust_Grenz} ) by the power semiconductor (E 3 ) flowing current (i _LH ) is controlled to a current above the permanently permissible current (i _{LH_Dauer} ) current (i _{LH_Grenz} ). Method according to one of the preceding claims, characterized in that for the power semiconductor ( 3 ) a value for the permanently permissible current (i _LH ) is set, and that in the monitoring device ( 5 ) no determination of the loss energy (E _loss ) and no control by the power semiconductor ( 3 ) current flowing (i _LH ) is performed when the by the power semiconductor ( 3 ) flowing current (i _LH ) essenli corresponds to the permissible current (i _{LH_Dauer} ). Device according to one of the preceding claims, characterized in that the monitoring device ( 5 ) is implemented as a software module. Device according to one of the preceding claims, characterized by their use in a pulse inverter an electric or hybrid vehicle. Method according to one of the preceding claims, characterized by its application in the control of a pulse inverter in an electric or hybrid vehicle.