DE102011113924A1 - Handheld device for measuring insulation resistance of high-voltage source for high voltage accumulator, has evaluation device which determines insulation resistance of high-voltage source from high and low ohm measurement values - Google Patents

Abstract

The handheld device (1) has probes (2a,2b) for contacting the reference compound and measuring points of high voltage source. A switching element (10) is provided for switching the handheld device between high impedance and low impedance partial measurement states. The evaluation device (12) is provided for automatically determining the insulation resistance of high-voltage source from high ohm measurement value and low ohm measurement value which are determined by measuring device (11) during high impedance and low impedance partial measurement states respectively. An independent claim is included for method for measuring insulation resistance of high-voltage source.

Description

Technical area:

The invention relates to a hand-held measuring device for measuring the insulation resistance of a high-voltage source with respect to a reference ground. The invention also relates to a method for measuring the insulation resistance with the hand-held measuring device and to the use of the hand-held measuring device for this method.

Background:

As part of technological development, high voltage sources are increasingly being used in the private sector as well. For example, electric or hybrid electric vehicles are equipped with high-voltage batteries, which have an operating voltage of 60 volts to 1,500 volts DC. Another technological area is the use of photovoltaic systems, which can also generate a DC voltage of over 1,000 volts due to the series connection of the photovoltaic modules.

For example from the ECE-R 100 There is a need to determine an insulation resistance of a high voltage source in a vehicle relative to the housing or other electrical ground. In the proposed measuring method, the resistance for both terminal poles of the high-voltage source is first measured in a high-resistance manner with respect to a ground and subsequently measured as low-resistance, and from this an insulation resistance between the terminal poles and the ground is determined.

To implement this provision, for example, in the document DE 103 04 234 A1 A method and apparatus for measuring insulation resistance in an electrical power system is described. This device is integrated in the energy system and has the advantage that the insulation resistance in the electrical energy system between a traction battery and a vehicle electrical system can be determined promptly.

For measuring such high voltage sources handheld devices for electricians or electronics are also quite common. Such hand-held measuring devices usually have two measuring tips, which can be manually set to two different measuring points during a measurement, wherein the hand-held measuring device can detect different electrical variables, such as a resistance, a voltage or a current, etc. and output them as a measured variable.

Description:

It is an aspect of the invention to propose a hand-held measuring device which has an extended range of functions. It is also an aspect of the invention to propose a method of measuring the insulation resistance of a high voltage source and the use of the handheld meter for this method.

For this purpose, a hand-held measuring device with the features of claim 1, a method with the features of claim 10 and a use with the features of claim 15 is proposed. Preferred or advantageous embodiments of the invention will become apparent from the dependent claims, the following description and the accompanying drawings.

The proposed measuring device is suitable and / or designed for measuring the insulation resistance of a high-voltage source with respect to a reference ground.

A hand-held measuring device is understood to mean, in particular, a measuring device intended for use. This can be expressed firstly by a low weight of less than 1 kilogram, preferably less than 500 grams and in particular less than 200 grams. The hand-held measuring device can have ergonomically shaped operating surfaces in order to simplify the operation of the hand-held measuring device to the user.

In particular, the hand-held instrument is designed to be energy-autonomous, so that it does not require any connection to a supply voltage during operation.

The high-voltage source is particularly preferably designed as a DC voltage source and preferably has a voltage of> 200 volts, preferably> 250 volts. As will be explained below, the high-voltage source may in particular be a high-voltage supply, in particular a high-voltage battery - also called a traction battery - in an electric or hybrid vehicle for providing the drive energy or, for example, a photovoltaic system.

In the former case, the reference ground is particularly preferably a housing of the high-voltage source and / or the ground or the negative pole of a 12-volt or 24-volt electrical system of the electric or hybrid vehicle. In the second-mentioned case, the reference mass may be a frame, a housing or an elevation of the photovoltaic modules in the photovoltaic system.

The hand-held measuring device comprises a first and a second measuring probe for contacting the reference mass or a measuring point of the high-voltage source. The measuring probes are particularly preferably designed as probe probes, in particular as test probes, and realized, for example, as metal tips. After-as will be explained later-the second measuring probe can be converted from one measuring point to another measuring point of the high-voltage source, it is particularly preferred that the second measuring probe is realized as a probe or test probe which is designed such that it is in operation must be actively pressed by a user against the measuring point to contact this non-positively and / or positively and produce sufficient electrical contact. In particular, the active pressing or frictional connection of the second measuring probe to the measuring point is absolutely necessary in order to establish an electrical contact.

The hand-held measuring device has a switching device for switching over the hand-held measuring device between a high-impedance and a low-impedance partial measurement.

In the partial measurement, the voltage drop is measured at a measuring resistor, which is connected between the first and the second measuring probe. In the case of the high-impedance partial measurement, the measuring resistance is greater than in the case of the low-resistance partial measurement. Particularly preferably, the high-impedance resistor is greater than or equal to 5 megohms, in particular greater than or equal to 7 megohms and in particular greater than or equal to 10 megohms. The low-impedance measuring resistor is preferably less than or equal to 1 megohm, preferably less than or equal to 500 kilohms and in particular less than or equal to 100 kilohms.

The hand-held measuring device further comprises a measuring device, which is designed to determine a high-ohm value for the high-resistance partial measurement and a low-ohm value for the low-resistance partial measurement.

mit:

R_i

Isolationswiderstand

R₀

Messwiderstand für die niederohmige Messung

U₁

Spannung bei der hochohmigen Teilmessung

U₂

Spannung bei der niederohmigen Teilmessung

The hand-held measuring device also has an evaluation device, which is designed to automatically determine the insulation resistance between the measuring point of the high-voltage source and the reference ground from the high-ohm measurement value and the low-ohm measurement value. The determination of the insulation resistance from the high-ohm value and the low-ohm value is, for example, in the aforementioned ECE-R 100: Edition 1997 given and done via the simple equation:

With:

R _i

insulation resistance

R ₀

Measuring resistor for the low-resistance measurement

U ₁

Voltage in the high-impedance partial measurement

U ₂

Voltage in the low-impedance partial measurement

Alternatively, the insulation resistance can also be determined via a characteristic field or a look-up table or matrix in the evaluation device. It is also possible that the determination of the insulation resistance according to other formulas, eg. B. according to other standards, such. B. the ECE-R: Edition 2010 he follows. It is also possible that the hand-held device switching over between different methods or formulas for determining the insulation resistance is switchable.

The advantage of the invention is to be seen in that a relatively simple evaluation step in the determination of the insulation resistance is automatically taken over by the hand-held measuring device and thereby repeatedly occurring errors in a manual calculation or in a manual determination based on a characteristic field are excluded. Particularly advantageously, the hand-held device can be used in a workshop or in field operation, since in these environments usually a writing space for recording the low-ohm value and the Hochohmmesswerts and to calculate the insulation resistance is simply missing, so that these values are noted in the short term and possibly incorrectly reproduced and further processed.

At the same time, a measuring device is proposed by the hand-held measuring device which can operate independently of self-test devices integrated in the vehicles or in the photovoltaic systems and, if appropriate, can serve as a reference measurement for checking the integrated measuring devices.

In a preferred embodiment of the invention, the partial measurement is carried out by evaluating a measuring voltage which is applied between the two measuring probes, wherein the measuring voltage is designed as the operating voltage of the high voltage source. The measuring voltage is thus not provided by the hand-held measuring device, but is measured at the active high-voltage source. For example, as a first measuring point of the high voltage source, a positive pole and as second measuring point of the high voltage source uses a negative pole.

In a preferred embodiment of the invention, the hand-held device has a preferably integrated display device for displaying the insulation resistance. This display device may optionally have a traffic light function, so z. B. at a low insulation resistance, a red light and a sufficient insulation resistance a green light lights up and / or as a numeric display, such as an LCD panel, be formed.

In a particularly preferred constructional realization, the first measuring probe is arranged in a first handpiece and the second measuring probe is arranged in a second handpiece, wherein the two handpieces are preferably directly connected to each other via a measuring cable. This structural design has already proven to be very advantageous in conventional handheld devices. In operation, the first hand part is gripped with a first hand and the second hand part with a second hand and the measuring probes are set to the reference mass or the measuring point. By arranged between the hand parts measuring cable handpieces are connected to each other captive and at the same time have enough room to move each other.

Particularly preferably, it is provided that the various devices, in particular the switching device, the measuring device and the evaluation device are arranged in one of the hand parts or distributed to the two hand parts. In this case, the hand-held measuring device consists only of the two handpieces and the measuring cable arranged in between.

In one possible embodiment, the switching device is designed as a manual switching device. This embodiment makes it possible to change the measuring resistor particularly preferably by a mechanical switching operation in the hand-held measuring device or to switch over from the high-impedance partial measurement to the low-impedance partial measurement. This embodiment is considered to be particularly robust. In one possible embodiment, a handset has a control button for switching, so that the user can conveniently switch the hand-held measuring device while the measuring probes lie against the reference mass or at the measuring point.

In one possible alternative, the switching device is designed as an automatic switching device, so that the switchover between the partial measurements takes place automatically within the scope of a measuring procedure.

In a particularly preferred embodiment of the invention, the evaluation device is designed to receive a first insulation resistance at a first measurement point and a second insulation resistance at a second measurement point and automatically determine the lower insulation resistance and - optionally complement - output. In this embodiment, a further measuring step, as this example, in the ECE-R 100 is required, taken from the hand-held device. Namely, the provision requires that the insulation resistance of a first pole of the high voltage source and of a second pole of the high voltage source be determined in each case with respect to the reference ground, wherein the lower insulation resistance represents the critical value. The automation of this evaluation step leads again to a simplification of the measurement and thus reduces the error rate of the measurement, as already discussed above.

In a particularly preferred embodiment of the invention, the hand-held measuring device comprises a control device, wherein the control device converts a fully automatic or a partially automatic measuring procedure for measuring the insulation resistance.

• a) Kontaktieren des Messpunkts und der Referenzmasse mit den Messsonden,
• b) Starten der vollautomatischen Messprozedur,
• c) Aufnahme des Hochohmmesswerts oder des Niederohmmesswerts,
• d) Automatisches Umschalten des Handmessgeräts,
• e) Aufnahme des anderen Ohmmesswerts,
• f) Automatisches Bestimmen des Isolationswiderstands.

In a first alternative embodiment, the switching device is formed automatically. A possible fully automatic measurement procedure looks as follows:

• a) contacting the measuring point and the reference mass with the measuring probes,
• b) starting the fully automatic measuring procedure,
• c) recording the high-ohm reading or the low-ohm reading,
• d) automatic switching of the hand-held measuring device,
• e) recording the other ohm reading,
• f) Automatic determination of the insulation resistance.

The user therefore only has to position the probes correctly, the measurement is carried out completely automatically. The measurement can be started, for example, by pressing a button on one of the two hand parts.

• a) Positionieren der beiden Messsonden auf einem ersten Messpunkt (erster Pol) und der Referenzmasse,
• b) Durchführung der Messung des Isolationswiderstands gemäß der vorhergehenden Alternative mit den Schritten b)–f),
• c) Umsetzen der zweiten Messsonde auf den zweiten Messpunkt (zweiter Pol),
• d) Wiederholung der Messprozedur der vorhergehenden Alternative mit den Schritten b)–f),
• e) Bestimmung des niedrigeren Isolationswiderstands aus den beiden Messungen.

A second alternative of the fully automatic measuring procedure can be implemented, for example, as follows:

• a) positioning the two measuring probes on a first measuring point (first pole) and the reference mass,
• b) carrying out the measurement of the insulation resistance according to the preceding alternative with the steps b) -f),
• c) converting the second measuring probe to the second measuring point (second pole),
• d) repetition of the measuring procedure of the preceding alternative with the steps b) -f),
• e) Determination of the lower insulation resistance from the two measurements.

In a semi-automatic measuring procedure, the manual switching device is particularly preferably used. Instead of an automatic switching of the hand-held measuring device (step d) of the preceding alternatives), a manual switching of the hand-held measuring device is implemented.

Another object of the invention relates to a method for measuring the insulation resistance with the hand-held measuring device, as described above or according to one of the preceding claims.

The method comprises the steps described below, which are preferably carried out in the order shown. In modified embodiments, steps can also be reversed.

In the method, the two probes are set to the reference ground or to the first measuring point of the high voltage source, wherein the contacting is done by the user hand-held. After contacting, the high-ohm value or the low-ohm value is recorded as a function of the measuring method set in the switching device. After one of the ohm readings has been taken, the switching device is switched so that a change takes place between the high-resistance and the low-resistance partial measurement. In a next step, the ohm reading is recorded, which was not recorded before. Based on the low-ohm reading and the high-ohm reading, the insulation resistance is automatically determined. After recording the second ohm reading, the contacting of the probes can be resolved again.

In one possible development of the invention, the same steps are carried out at a second measuring point of the high-voltage source in order to determine a second insulation resistance. The steps of the method may be performed in the order as set forth in the preceding claim, but a different order may be chosen. So it is z. For example, it is possible to determine the first and second insulation resistance only after completion of the recording of the high-ohm measurement value or the low-ohm measurement value of the second measurement point.

In a continuation of the method, it is provided that an automatic comparison of the first insulation resistance with the second insulation resistance is performed and the value of the lower insulation resistance is output.

It is particularly preferred if the method for measuring the insulation resistance of a high voltage source, in particular a high voltage battery - also called traction battery - is used in an electric or hybrid vehicle, wherein the high voltage source is designed to provide the drive energy. By the method, the reliability of the electric or hybrid vehicle can be increased.

In another alternative of the method, the high voltage source is designed as a photovoltaic system, wherein the insulation resistance between a first and a second pole of photovoltaic modules on the one hand and a frame, housing or a Aufständerung the photovoltaic system on the other hand is measured.

A final subject relates to the use of the hand-held measuring device as described above or according to one of the preceding figures in a method as described above or in one of the preceding claims and / or for measuring the insulation resistance in a high-voltage source, in particular high-voltage accumulator , in an electric or hybrid vehicle to provide the drive power or a photovoltaic system.

Further features, advantages and effects of the invention will become apparent from the following description of a preferred embodiment of the invention and the accompanying figures. Showing:

1 a schematic representation of a hand-held measuring device as an embodiment of the invention;

2a , b shows a schematic circuit diagram for illustrating a high-resistance and a low-resistance partial measurement for an insulation resistance measurement at a first pole at a high-voltage source;

3a , b shows a schematic circuit diagram for illustrating a high-resistance and a low-resistance partial measurement for an insulation resistance measurement at a second pole at a high-voltage source;

4 a flowchart for explaining the measuring procedure for measuring the insulation resistance at the high voltage source with the hand-held device.

Corresponding or identical parts are each provided with the same reference numerals in the figures.

The 1 shows a highly schematic representation of a hand-held device 1 , which is designed for insulation resistance measurement at a high voltage source. The hand-held device 1 is designed as a 2-pole measuring device and has two measuring probes 2a , b on, each on a handpiece 3a respectively. 3b are arranged. The probes 2a , b are as contact tips z. B. formed of metal. They may be formed as peaks, as shown schematically, in alternative embodiments these are measuring probes 2a , b, for example, mushroom-shaped.

The two hand parts 3a , b are via a measuring cable 4 connected to each other via which a measuring current can flow or over which a measuring voltage can be applied.

The two hand parts 3a , b have ergonomically shaped brackets 5a , b on what a simple gripping and holding the hand parts 3a to enable b in use. For example, the brackets 5a , b formed from a soft rubber or have corrugations on.

The hand-held device 1 is designed to carry out the measurement of the insulation resistance, as described below with reference to 2a , b or 3a , b is explained.

In the 2a is a high voltage source 6a , shown as a high voltage accumulator in an electric or hybrid vehicle for providing drive energy. Such high voltage batteries 6 typically have an operating voltage between 60 volts and 300 volts DC. The high voltage accumulator 6 has a plus pole 7a and a negative pole 7b on, over which the high voltage accumulator 6 with an energy system 8th the electric or hybrid vehicle is connected. The energy system 8th is electrically isolated to a housing of the power system 8th or a body of the electric or hybrid vehicle as a reference mass 9 arranged. The aim of insulation resistance measurement is to measure the resistance between the energy system 8th and the reference mass 9 to investigate.

For this purpose, in a first step, the first probe 2a with the reference mass 9 and the second probe 2 B with the negative pole 7b contacted. The contacting is done manually, ie the probes 2a , b be on the case or the body as a reference mass 9 or the negative pole 7b put on and pressed.

The 4 shows a flowchart illustrating the flow of the measurement, this contacting step with the reference numeral 100 is designated.

In a next step 200 is carried out a high-impedance partial measurement, wherein a voltage U1 is determined, which drops at a first measuring resistor, not shown, in series between the negative pole 7b and the reference mass 9 is switched. This first measuring resistor is in the hand-held measuring device 1 integrated and has a value of z. B. 10 megohms.

In a next step 300 ( 4 ), the type of measurement is switched by a second measuring resistor R0 also in series between the negative pole 7b and the reference mass 9 , however, is set in parallel to the first measuring resistor, as shown in the 2 B is shown. The second measuring resistor R0 is smaller than the first measuring resistor and has, for example, a value <1 megohm.

In one step 400 a low-resistance partial measurement is carried out, wherein the voltage U2 which drops at the second measuring resistor R0 is measured.

It should be noted that the measuring voltage, which is the handheld 9 for the partial measurements, by the high voltage accumulator 6 provided.

In a next step 500 ( 4 ), the insulation resistance Ri_minus between the negative pole 7b and the reference mass 9 determined according to the following equation:

In the 3a , b is the circuit design for measuring the insulation resistance Ri_plus between the positive pole 7a and the reference mass 9 shown, wherein the measurement analogous to the measurement of the insulation resistance Ri_minus of the negative pole 7b takes place so that on the description to the 2a , b or the 4 is referenced. The insulation resistance Ri_plus between the positive pole 7a and the reference mass 9 is determined according to the following equation:

After determining the first insulation resistance Ri_minus between negative pole 7b and reference mass 9 and the second insulation resistance Ri_plus between positive pole 7a and reference mass 9 In an optional, further method step, the lower resistance value is determined.

bzw.Instead of the formulas mentioned, it is also possible to use formulas which take into account the first measuring resistor R1:

respectively.

The hand-held device 1 has a switching device for carrying out the method 10 on which the switching between the high-impedance ( 2a and 3a ) and the low-resistance ( 2 B and 3b ) Partial measurement allows. This switching can, for example, and as in the 1 shown schematically by pressing a button, in modified embodiments, the switching can also happen automatically.

Furthermore, the hand-held device includes 1 a measuring device 11 which determines the high-ohm value U1 or U1 'and the low-ohm value U2 or U2'. An evaluation device 12 is designed to automatically determine the insulation resistance Ri_minus, Ri_plus from the high-ohm measurement value U1, U1 'and the low-ohm value U2, U2' and optionally additionally on a display device 13 display.

The hand-held device 1 is characterized by a very simple and compact design. So all the necessary components are on the two hand parts 3a , b distributed, which only over the measuring cable 4 connected to each other.

In possible embodiments of the invention, the measurement of one of the insulation resistors Ri_minus, Ri_plus can also be fully automatic. For this the measuring probes become 2a , b on one of the poles 7a , b and on the reference mass 9 The acquisition of the high-ohm value U1 or U1 ', the low-ohm value U2 or U2' and the switching of the type of measurement is automated, so that after starting the measurement procedure, the user only has to wait for the indication of the insulation resistance value Ri_minus or Ri_plus.

While at least one embodiment has been disclosed in detail above, it is to be appreciated that a variety of variations of the invention exist. It should also be appreciated that the at least one embodiment is merely exemplary in nature and is not intended to limit the scope, fields of application, or configuration. Rather, the present disclosure should be a pleasant roadmap for implementing at least one embodiment. Thus, it should be recognized that various variations in the function or arrangement of elements of the at least one embodiment may be employed without departing from the scope defined by the claims and their legal equivalents.

LIST OF REFERENCE NUMBERS

1

handheld instrument

2a, b

probe

3a, b

handpiece

4

Leads

5a, b

ergonomically shaped brackets

6

Hochspannungsakkumulator

7a

positive pole

7b

minuspol

8th

energy system

9

reference mass

10

switchover

11

measuring device

12

evaluation

13

display

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10304234 A1 [0004]

Cited non-patent literature

• ECE-R 100 [0003]
• ECE-R 100: Edition 1997 [0017]
• ECE-R: Edition 2010 [0018]
• ECE-R 100 [0027]

Claims (15)

Handheld measuring device ( 1 ) for measuring the insulation resistance (Ri_minus, Ri_plus) of a high voltage source ( 6 ) compared to a reference mass ( 9 ) with a first measuring probe ( 2a ) for contacting the reference mass ( 9 ), with a second measuring probe ( 2 B ) for contacting a measuring point ( 7a , b) the high voltage source ( 6 ), with a switching device ( 10 ) for switching the hand-held measuring device ( 1 ) between a high-impedance and a low-resistance partial measurement, with a measuring device ( 11 ), which is designed to determine a high-ohm value (U1, U1 ') in the case of the high-resistance partial measurement and a low-ohm value (U2, U2') in the case of the low-resistance partial measurement, and to an evaluation device ( 12 ), which is designed to automatically determine the insulation resistance (Ri_minus, Ri_plus) from the high-ohm value (U1, U1 ') and the low-ohm value (U2, U2'). Handheld measuring device ( 1 ) according to claim 1, characterized in that the partial measurement is carried out by evaluation of a measuring voltage, wherein the measuring voltage as the operating voltage of the high voltage source ( 6 ) is trained. Handheld measuring device ( 1 ) according to claim 1 or 2, characterized by a display device ( 13 ) for indicating the insulation resistance (Ri_minus, Ri_plus). Handheld measuring device ( 1 ) according to one of the preceding claims, characterized in that the first measuring probe ( 2a ) in a first hand part ( 3a ) and the second measuring probe ( 2 B ) in a second handpiece ( 3b ), wherein the two hand parts ( 3a , b) via a measuring cable ( 4 ) are preferably connected directly to each other. Handheld measuring device ( 1 ) according to claim 4, characterized in that the switching device ( 10 ), the measuring device ( 11 ) and the evaluation device ( 12 ) in one of the hand parts ( 3a , b) arranged or on the two hand parts ( 3a , b) are distributed. Handheld measuring device ( 1 ) according to one of the preceding claims, characterized in that the switching device as a manual switching device ( 10 ) is trained. Handheld measuring device ( 1 ) according to one of claims 1 to 5, characterized in that the switching device ( 10 ) is formed as an automatic switching device. Handheld measuring device ( 1 ) according to one of the preceding claims, characterized in that the evaluation device ( 12 ) is formed, a first insulation resistance (Ri_minus) at a first measuring point ( 7b ) and a second insulation resistance (Ri_plus) at a second measuring point ( 7a ) and automatically determine the lower insulation resistance and - optionally supplementary - output. Handheld measuring device ( 1 ) according to one of the preceding claims, characterized by a control device, wherein the control device converts a fully automatic or semi-automatic measuring procedure for measuring the insulation resistance (Ri_minus, Ri_plus). Method for measuring an insulation resistance (Ri_minus) with the hand-held measuring device ( 1 ) according to one of the preceding claims, characterized by the steps: - contacting the first measuring probe with the reference mass ( 100 ); Contacting the second measuring probe with a first measuring point of the high voltage source ( 100 ); - recording the high-ohm reading or low-ohm reading ( 200 ); - Switching the hand-held measuring device ( 300 ); - recording the low-ohm value or the high-ohm value ( 400 ); - automatic determination of the insulation resistance ( 500 ). Method according to claim 10, characterized by a processing of the steps of claim 10 at a second measuring point ( 7b ) of the high voltage source ( 6 ) for determining a second insulation resistance (Ri_plus). A method according to claim 11, characterized by an automatic comparison of the first insulation resistance (Ri_minus) with the second insulation resistance (Ri_plus). Method according to one of claims 10 to 12, characterized in that the high voltage source ( 6 ), in particular as a high-voltage accumulator, is designed in an electric or hybrid vehicle for providing the drive energy. Method according to one of claims 10 to 12, characterized in that the high voltage source ( 6 ) is designed as a photovoltaic system. Use of the hand-held measuring device ( 1 ) according to one of claims 1 to 9 for measuring the insulation resistance (Ri_minus, Ri_plus) at a high voltage source ( 6 ), in particular high-voltage accumulator, in an electric or hybrid vehicle to provide the drive energy or a photovoltaic system.

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