KR101619328B1 - Apparatus for measuring isolation resistance and method thereof - Google Patents

Abstract

An embodiment of the present specification relates to an apparatus for measuring an insulation resistance and a method thereof. The apparatus for measuring an insulation resistance comprises: a first resistance, a measuring capacitor and a second resistance connected to a battery in series; first and second switches connecting or disconnecting a line between the battery and the first and second resistances; a third switch having one side connected between the first resistance and the measuring capacitor and the other side connected to a chassis ground of a vehicle; a fourth switch having one side connected between the measuring capacitor and the second resistance and the other side connected to the third switch and the ground; one side and the other side of common resistances connected in parallel to the first resistance and the second resistance, respectively; a voltage measuring circuit having both ends connected to the measuring capacitor to measure a capacitor voltage; and a control unit controlling the first and second switches according to whether dielectric breakdown occurs due to one side fault resistance by calculating a combined resistance in which the one side fault resistance, the one side common resistance and the first resistance are combined in parallel by using a battery voltage and a capacitor voltage measured by alternatively turning on the third switch or the fourth switch, when the one side fault resistance connected to the one side common resistance in parallel is generated.

Description

TECHNICAL FIELD [0001] The present invention relates to an insulation resistance measuring apparatus,

The present invention relates to an insulation resistance measuring apparatus and a method thereof, and more particularly, to an insulation resistance measuring apparatus and method capable of preventing a peak voltage generated when a switch for insulation resistance measurement is closed through a measuring capacitor .

In recent years, various devices such as industrial devices, home appliances and automobiles using high-voltage batteries have appeared, and especially in the field of automobile technology, the use of high-voltage batteries is becoming more active.

Automobiles that use internal combustion engines that use fossil fuels such as gasoline or heavy oil as the main fuel have a serious impact on pollution such as air pollution. Therefore, in recent years, efforts have been made to develop electric vehicles or hybrid electric vehicles (HEVs) to reduce pollution.

Electric vehicles (EVs) are vehicles that do not use petroleum fuels and engines but use electric batteries and electric motors. In other words, although an electric vehicle that drives a car by rotating an electric motor that is stored in a battery has been developed before a gasoline car, it has not been put into practical use due to problems such as a heavy weight of a battery and a time required for charging. Recently, And research for commercialization began in the 1990s.

On the other hand, hybrid technology (HEV) that uses electric vehicles, fossil fuels and electric energy adaptively is being commercialized as battery technology has been developed remarkably.

Since HEV uses both gasoline and electricity as power sources, it is receiving positive reviews in terms of fuel efficiency improvement and emission reduction. It is expected that HEV will play an intermediate role in evolving into a full electric vehicle because it is important to overcome the price difference with gasoline automobile by reducing the amount of secondary battery to one third of that of electric cars.

Since HEV and EV vehicles using such electric energy use a battery in which a plurality of rechargeable secondary cells are packed as a main power source, there is no exhaust gas and noise is small. have.

Since the performance of a battery using the electric energy directly affects the performance of the vehicle, it is necessary to measure the voltage of each battery cell, the voltage and current of the entire battery, and to efficiently manage charge and discharge of each battery cell However, a battery management system (BMS: Battery Management System) is required to monitor the state of a cell sensing IC that senses each battery cell and to control the corresponding cell stably.

Generally, a method for detecting a battery voltage in a battery management system (BMS) includes a method using an operational amplifier (OP Amp.) And a method using a relay and a condenser. Among them, a relay and a capacitor use a relay to charge a capacitor of a battery and convert the charging voltage into an analog / digital converter (A / D converter).

On the other hand, hybrid cars and electric vehicles using high voltage batteries have a system that automatically turns off the main high voltage battery in the event of an emergency. In this case, emergency refers to excessive short circuit or insulation breakdown due to short circuit caused by excessive short circuit or insulation break due to aging of the related parts, or component breakage due to external impact.

When an emergency occurs in the vehicle, a command to cut off the main power from the higher-level parts for controlling the high-voltage parts such as the BMS (Battery Management System) and the HCU (Hybrid Control Unit) is issued and the power is interrupted. In this case, the high voltage related parts are monitored by voltage or current of the line connecting the power supply through a series of programs or sensors, so that when voltage or current outside the normal range is detected, or leakage current is over the allowable value, The main power is cut off through CAN communication or signal transmission.

Thus, measurement of insulation resistance is very important in a hybrid vehicle using a high-voltage battery.

Here, there is a method of measuring the leakage current between a high-voltage battery and a hybrid vehicle to destroy the insulation and force the direct current to flow. This method has a disadvantage in that the insulation breaks down while measuring the insulation resistance.

To solve this problem, there is a method of connecting a coupling capacitor between a high voltage battery and a hybrid vehicle, and applying an AC signal to the coupling capacitor to measure an insulation resistance component. However, this method has a disadvantage in that it requires a circuit to pass through the same circuit for charging and discharging the coupling capacitor. Therefore, the conventional dielectric breakdown measuring circuit has a small voltage fluctuation range There is a problem that accurate judgment is difficult.

In addition, the conventional dielectric breakdown measuring circuit can measure the dielectric breakdown of each of the positive electrode and the negative electrode of the high voltage line connected to the battery, but can not measure the dielectric breakdown when the dielectric breakdown occurs simultaneously in the positive electrode and the negative electrode have.

In addition, the conventional dielectric breakdown measuring circuit may cause a peak voltage due to the switching of the switch for measuring the insulation resistance. Because of this peak-to-peak voltage, the variation in the voltage across the measurement resistance can be large. As a result, errors in the measurement of the insulation resistance for the insulation breakdown measurement may occur.

Embodiments of the present invention provide an insulation resistance measuring apparatus and a method of measuring an insulation resistance based on a voltage applied to a measurement capacitor and capable of preventing a peak voltage generated when a switch for insulation resistance measurement is closed do.

In addition, the embodiments of the present invention can accurately calculate the insulation resistance so that the composite resistance, in which the anode or the cathode common resistance and the anode or cathode resistance are connected in parallel, is calculated and the insulation between the high voltage line of the hybrid car or the electric vehicle and the chassis ground It is an object of the present invention to provide an insulation resistance measuring apparatus and method which can measure an insulation breakdown even when an anode or a cathode of a high voltage line connected to a battery is destroyed by insulation or an anode and a cathode are insulation destroyed by measuring breakdown.

According to a first aspect of the present disclosure there is provided a battery comprising: a first resistor, a measurement capacitor, and a second resistor serially connected to the battery; First and second switches connecting or disconnecting the line between the battery and the first resistor and the second resistor; A third switch having one side connected between the first resistor and the measuring capacitor and the other side connected to the chassis ground of the vehicle; A fourth switch having one side connected between the measuring capacitor and the second resistor and the other side connected to the third switch and the ground; One and the other common resistors connected in parallel with the first resistor and the second resistor, respectively; A voltage measuring circuit connected at both ends to the measuring capacitor to measure a capacitor voltage; And a second common resistor connected in parallel to the first common resistor and the third common resistor, wherein the third switch or the fourth switch is alternately turned on, and the one-side fault resistance, And a control unit for controlling the first and second switches according to whether the insulation resistance is broken due to the one-side fault resistance by calculating a combined resistance obtained by combining the first resistors in parallel.

Wherein the control unit turns on and off the third and fourth switches respectively when a positive polarity breakdown resistance connected in parallel with the positive common resistance is generated between the positive terminal of the battery and the first resistance, The anode breakdown resistance can be calculated by using the voltage across the common cathode resistance and the measured capacitor voltage in which the voltage is distributed in proportion to the cathode common resistance.

The control unit turns off and on the third and fourth switches, respectively, when a cathode fault resistance connected in parallel with the cathode common resistance occurs between the anode terminal and the second resistance of the battery, The cathode fault resistance can be calculated using the voltage across the anode common resistance divided by the voltage proportional to the anode common resistance and the measured capacitor voltage.

When the control unit turns on and off the third and fourth switches, the voltage across the measured measuring capacitor may have the same value as the voltage across the common cathode resistance.

When the control unit turns off and on the third and fourth switches, the voltage across the measured measuring capacitor may have the same value as the voltage across the common anode resistance.

According to a second aspect of the present invention, there is provided a method of measuring an insulation resistance in an insulation resistance measuring apparatus including a first resistor, a measurement capacitor, and a second resistor connected in series to a battery, 1 resistor, a measurement capacitor and a second resistor; A third switch having one side connected between the first resistor and the measuring capacitor and the other side connected to the chassis ground of the vehicle, and a second switch having one side connected between the measuring capacitor and the second resistor and the other side connected to the third switch and the ground Measuring a capacitor voltage by alternately turning on and off a fourth switch to be connected; Calculating a combined resistance in which one side fault resistor, one side common resistor and a first resistor are combined in parallel using the measured capacitor voltage and the battery voltage when one side fault resistor connected in parallel with the one side common resistor occurs; And calculating a one-side common resistance and a one-side fault resistance connected in parallel with the first resistor from the calculated combined resistance.

The method includes determining whether the breakdown is an insulation breakdown according to the calculated breakdown resistance, maintaining the connection of the first and second switches if the breakdown is not broken according to the determination result, and disconnecting the first and second switches The method comprising the steps of:

Wherein the step of calculating the one-side fault resistance includes turning on and off the third and fourth switches, respectively, when an anode fault resistance connected in parallel with the anode common resistance occurs between the anode terminal and the first resistor of the battery, OFF), it is possible to calculate the anode breakdown resistance by using the voltage caught by the cathode common resistance and the measured capacitor voltage, the voltage of which is proportional to the common resistance and the cathode common resistance.

Wherein the step of calculating the one-side fault resistance comprises: turning off the third and fourth switches when the negative terminal resistance is connected in parallel with the negative common resistance between the negative terminal and the second resistor of the battery, ON), the cathode fault resistance can be calculated using the voltage across the anode common resistance, which is proportional to the combined resistance and the anode common resistance, and the measured capacitor voltage.

When the third and fourth switches are turned on and off, respectively, the voltage across the measured measuring capacitor may have the same value as the voltage across the common cathode resistance.

When the third and fourth switches are turned off and turned on respectively, the voltage across the measured measuring capacitor may have the same value as the voltage across the common anode resistance.

Embodiments herein can prevent peak voltages that occur when the switch for insulation resistance measurement is closed by measuring the insulation resistance based on the voltage across the measurement capacitor.

In addition, the embodiments of the present invention can accurately calculate the insulation resistance so that the composite resistance, in which the anode or the cathode common resistance and the anode or cathode resistance are connected in parallel, is calculated and the insulation between the high voltage line of the hybrid car or the electric vehicle and the chassis ground By measuring the breakdown, the breakdown of the insulation can be measured even if the anode or cathode of the high voltage line connected to the battery is destroyed or at the same time the anode and the cathode are broken.

1 is a block diagram of an insulation resistance measuring apparatus according to an embodiment of the present invention.
2 is an explanatory diagram of a switching operation for measuring an anode fault resistance according to an embodiment of the present invention.
3 is an explanatory diagram of a switching operation for measuring a cathode fault resistance according to an embodiment of the present invention.
4 is a flowchart illustrating a method of measuring insulation resistance according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the embodiments, descriptions of techniques which are well known in the technical field to which this specification belongs and which are not directly related to this specification are not described. This is for the sake of clarity without omitting the unnecessary explanation and without giving the gist of the present invention.

For the same reason, some of the components in the drawings are exaggerated, omitted, or schematically illustrated. Also, the size of each component does not entirely reflect the actual size. In the drawings, the same or corresponding components are denoted by the same reference numerals.

1 is a block diagram of an insulation resistance measuring apparatus according to an embodiment of the present invention.

1, an insulation resistance measuring apparatus 100 according to an embodiment of the present invention includes a first resistor R1, a second resistor R2, a measurement capacitor Cm, Third and fourth switches SW3 and SW4, a voltage measuring circuit 110, and a control unit 120. The first and second switches SW1 and SW2,

Unlike FIG. 1 of this specification, when the insulation resistance is measured using the measurement resistance, the peak voltage generated when the switch for measuring the insulation resistance is closed can not be prevented. That is, an actual system including the battery Vb or the fuel cell may be configured such that the voltage level applied to the measurement resistor varies depending on the state of charge of the battery Vb, the power generation state of the fuel cell, Lt; / RTI > Such high voltage fluctuation may cause a large measurement error when measuring the insulation resistance using the voltage across the measurement resistance.

However, as shown in FIG. 1 according to an embodiment of the present invention, the insulation resistance measuring apparatus 100 may include a measurement capacitor (not shown) capable of preventing a peak voltage generated when the third switch SW3 or the fourth switch SW4 is closed, By measuring the insulation resistance through the voltage applied to the battery Cm, the measurement error can be reduced to more accurately measure the insulation breakdown between the battery Vb and the chassis ground.

The specific configuration and operation of each component of the insulation resistance measuring apparatus 100 of FIG. 1 will be described below.

First, the battery Vb may be a hybrid battery or a high voltage battery mounted in an electric vehicle. The battery Vb may be a high-voltage battery, or may be implemented as a single battery, or a battery pack in which a plurality of batteries are connected in series. This is because, in order to generate a high voltage, it is more efficient to generate a high voltage by serially connecting a plurality of batteries generating a low voltage rather than directly generating a high voltage with a single battery in a method commonly used in electric vehicles. The fuel cell may be replaced by a battery. The battery Vb may include various kinds of batteries requiring measurement of insulation resistance. At this time, the high voltage lines connected to the positive terminal (+) and the negative terminal (-) of the battery (Vb) are electrically insulated.

As shown in FIG. 1, a positive common resistance Ry + and a negative common resistance Ry- are formed in series, and a chassis ground (GND) grounded to the chassis of the vehicle is connected between these common resistors. The chassis ground is an object to be insulated from the battery (Vb) and the fuel cell system and the battery and the fuel cell. When the system using the battery and the fuel cell is an automobile, the vehicle body may become chassis ground.

The insulation resistance measuring apparatus 100 is connected to the battery Vb through the first and second switches SW1 and SW2.

The first resistor R1, the measurement capacitor Cm and the second resistor R2 are connected in series to the battery Vb. Here, the first resistor R1 and the second resistor R2 may be formed of a plurality of resistors, respectively. When the first resistor R1 is composed of a plurality of resistors, one side of the third switch SW3 may be connected between the plurality of resistors. When the second resistor R2 is composed of a plurality of resistors, one side of the fourth switch SW4 may be connected between the plurality of resistors.

The first switch SW1 connects or disconnects the line between the battery Vb and the first resistor R1. Further, the second switch SW2 connects or disconnects the line between the battery Vb and the second resistor R2. The first and second switches SW1 and SW2 are provided on the circuit connected in series to open and close the circuit. The first and second switches SW1 and SW2 may be provided on a line connecting the positive terminal of the battery Vb and the first resistor R1 or may be connected to the negative terminal of the battery Vb and the second resistor R2, And the like. Thus, the operation of the first and second switches SW1 and SW2 allows current to flow through the resistance and the measurement capacitor Cm.

The first and second switches SW1 and SW2 are connected to a line connecting the positive terminal of the battery Vb and the first resistor R1 and a line connecting the negative terminal of the battery Vb and the second resistor R2 Respectively. That is, the first resistor R1, the measuring capacitor Cm and the second resistor R2, and the voltage measuring circuit 110 are connected to each other by opening and closing the circuit by providing two first and second switches SW1 and SW2, And the like can be protected.

The first and second switches SW1 and SW2 and the third and fourth switches SW3 and SW4 may be photo-MOS relays.

PhotomOS relay is a type of photocoupler that is combined with light using LED and closes when receiving light. PhotoMOS relays have a faster response time and higher sensitivity than general mechanical relays, have a long lifetime and do not have chattering phenomena (for example, repeated on and off several times in a very short time without turning on and off at once) More accurate measurement results can be obtained.

The third switch SW3 has one side connected between the first resistor R1 and the measuring capacitor Cm and the other side connected to the chassis ground of the vehicle.

The fourth switch SW4 has one side connected between the measuring capacitor Cm and the second resistor R2 and the other side connected to the third switch SW3 and the chassis ground.

That is, a branch is formed between the first resistor R1 and the measurement capacitor Cm and between the measurement capacitor Cm and the second resistor R2. The third and fourth switches SW3 and SW4 and the measuring capacitor Cm are connected in parallel. The line connecting the third switch SW3 and the fourth switch SW4 is grounded to form a chassis ground.

One side common resistance Ry + or Ry- is connected in parallel with the first resistor R1. The other common resistance Ry- or Ry + is connected in parallel with the second resistor R2. Here, one side common resistance (Ry + or Ry-) may have tens to several hundreds of M [Omega].

The voltage measuring circuit 110 is connected at both ends to the measuring capacitor Cm to measure the capacitor voltage Vcap. The voltage measurement circuit 110 may include an operational amplifier (Op Amp) to measure the capacitor voltage Vcap.

The control unit 120 controls the overall operation of the insulation resistance measuring apparatus 100. To this end, the control unit 120 controls the switching of the first to fourth switches SW1 to SW4 or receives the measured capacitor voltage Vcap from the measurement capacitor Cm through the voltage measurement circuit 110.

On the other hand, a failure may occur between the battery Vb and the chassis of the vehicle. Then, one side fault resistance (Rf + or Rf-) can be generated by being connected in parallel with the one side common resistance (Ry + or Ry-) and the first resistor (R1). In Fig. 1, the one-side fault resistance (Rf + or Rf-) is shown by a dotted line. For example, the one-side fault resistance (Rf + or Rf-) may be several to several tens of kilohms. The anode breakdown resistor Rf + connected between the anode of the battery Vb and the chassis ground may be represented by an equivalent resistance of the insulation resistance that may occur between the anode of the battery Vb and the chassis ground. Similarly, the cathode fault resistance Rf- connected between the cathode of the battery Vb and the chassis ground may represent an equivalent resistance of the insulation resistance that may occur between the cathode of the battery Vb and the chassis ground.

The insulation resistance measuring apparatus 100 divides the breakdown resistance between the battery Vb and the chassis ground into an anode and a cathode so that the breakdown resistance across the battery Vb can be separately measured. This is to make it easy to understand the safety problem and the location of the insulation breakdown when the breakdown resistance occurs.

The control unit 120 alternately turns on the third switch SW3 or the fourth switch SW4 when one side fault resistor Rf + or Rf- connected in parallel with the common resistor Ry + or Ry- ) To calculate a combined resistance (Rf + // Ry + // R1) using the measured capacitor voltage (Vcap) and battery voltage (Vb). Here, the synthetic resistor is a resistor (Rf + // Ry + // R1 or Rf- // Rf +) obtained by combining the one side resistance Rf + or Rf-, the one side common resistance Ry + or Ry- Ry - // R2). Then, the controller 120 calculates the one-side fault resistance Rf + or Rf- by using the calculated combined resistance, the other common resistance Ry- or Ry +, the measured battery voltage Vb, and the capacitor voltage Vcap . The control unit 120 can control the first and second switches SW1 and SW2 according to whether the insulation failure is caused by the calculated one-side fault resistance (Rf + or Rf-).

At this time, the voltage applied to the measuring capacitor Cm may vary depending on opening and closing of the third switch SW3 and the fourth switch SW4. It can also be influenced by the anode common resistance Ry + and the cathode common resistance Ry-. That is, the capacitor voltage Vcap applied to the measuring capacitor Cm measured through the voltage measuring circuit 110 when only the third switch SW3 is closed and the capacitor voltage Vcap applied to the voltage measuring circuit The capacitor voltage Vcap applied to the measurement capacitor Cm measured through the resistor Rd may be correlated to the anode common resistance Ry + and the cathode common resistance Ry-. The controller 120 uses the capacitor voltage Vcap measured when only the third switch SW3 is closed and the capacitor voltage Vcap measured when only the fourth switch SW4 is closed to determine the insulation breakdown of the high- Can be measured.

Here, one side in FIG. 1 represents the polarity of either the positive (+) or negative (-) side, and the other side shows the opposite polarity to any one of the polarities, but can be represented by the opposite polarity. As described above, the insulation resistance measuring apparatus 100 of the present invention can measure the insulation resistance when one of the positive electrode and the negative electrode of the high voltage line connected to the battery Vb is insulated, and at the same time, The insulation resistance can be measured.

Hereinafter, for explanation of this specification, one side common resistance Ry + or Ry- is defined as the anode common resistance Ry + and the other side common resistance Ry- or Ry + is defined as the cathode common resistance Ry- do. The one-side fault resistance (Rf + or Rf-) is defined as the anode fault resistance (Rf +), and the other-side fault resistance is defined as the cathode fault resistance (Rf-).

Thus, the controller 120 can determine that the insulation breakdown occurs when the measured anode or cathode breakdown resistance (Rf + or Rf-) is lower than a specific resistance value.

2 is an explanatory diagram of a switching operation for measuring an anode fault resistance according to an embodiment of the present invention.

The case where the positive polarity common resistance Ry + and the positive polarity negative polarity resistance Rf + connected in parallel are generated will be described in detail.

2, when the positive polarity resistance Rf + connected in parallel with the positive common resistance Ry + is generated between the positive terminal of the battery Vb and the first resistor R1, 3 and the fourth switches SW3 and SW4 are turned ON and OFF respectively so that the voltage across the anode common resistance Ry- obtained by dividing the voltage in proportion to the combined resistance and the cathode common resistance Ry- Vy-) is used to calculate the anode breakdown resistance (Rf +) as shown in the following equation (1).

When the control unit 120 turns on and off the third and fourth switches SW3 and SW4 respectively, the voltage across the measurement capacitor Cm measured by the voltage measurement circuit 110 becomes negative Has the same value as the voltage (Vy-) caught by the common resistor Ry-.

Here, Vy- is the voltage across the cathode common resistance Ry-, Vb is the measured battery voltage, Rf + is the anode fault resistance, Ry- is the cathode common resistance, Ry + is the anode common resistance, and Vcap is the voltage across the measurement capacitor Cm The applied voltage represents the capacitor voltage.

3 is an explanatory diagram of a switching operation for measuring a cathode fault resistance according to an embodiment of the present invention.

Next, a case where a negative-electrode breakdown resistor Rf- connected in parallel with the negative common resistor Ry- occurs will be described in detail.

3, when the negative terminal resistance Rf- connected in parallel with the negative common resistance Ry- is generated between the negative terminal of the battery Vb and the second resistor R2, And the voltage across the positive common resistance Ry +, which is a voltage divided in proportion to the composite resistance Ry +, by turning off the third and fourth switches SW3 and SW4, respectively, Vy +) is used to calculate the cathode resistance Rf- as shown in the following equation (2).

Here, when the control unit 120 turns off and on the third and fourth switches SW3 and SW4, the voltage across the measuring capacitor Cm measured by the voltage measuring circuit 110 becomes positive Has the same value as the voltage (Vy +) across the common resistance Ry +.

Here, Vy + is the voltage across the anode common resistance Ry +, Vb is the measured battery voltage Vb, Rf- is the cathode fault resistance Rf-, Ry + is the anode common resistance Ry + Ry-) and Vcap represents a capacitor voltage (Vcap) across the measurement capacitor (Cm).

4 is a flowchart illustrating a method of measuring insulation resistance according to an embodiment of the present invention.

A method of calculating the anode fault resistance (Rf +) in the insulation resistance measuring apparatus (100) will be described first, and a method of calculating the cathode fault resistance (Rf-) will be described below.

First, the steps S402 to S416 for calculating the anode fault resistance (Rf +) will be described as follows.

The insulation resistance measuring apparatus 100 turns on the first and second switches SW1 and SW2 (S402).

The first and second switches SW1 and SW2 are closed to measure the insulation breakdown of the high voltage line connected to the positive terminal and the negative terminal of the battery Vb so that the battery Vb and the first resistor R1, So that the measuring capacitor Cm and the second resistor R2 are connected so that the voltage is applied to the resistors and the measuring capacitor Cm.

Then, the insulation resistance measuring apparatus 100 turns on the third switch SW3 (S404).

Thereafter, the insulation resistance measuring apparatus 100 measures the capacitor voltage Vcap caught by the measurement capacitor Cm (S406).

That is, the insulation resistance measuring apparatus 100 measures the voltage across the measuring capacitor Cm through the voltage measuring circuit 110 while the third switch SW3 is closed and the fourth switch SW4 is opened. At this time, when the third and fourth switches SW3 and SW4 are turned ON and OFF, respectively, the voltage across the measured measuring capacitor Cm becomes equal to the voltage caught by the cathode common resistance Ry- Respectively.

Next, the insulation resistance measuring apparatus 100 measures the battery voltage Vb through the voltage measuring circuit 110 (S408).

Then, the insulation resistance measuring apparatus 100 calculates a combined resistance (Rf + // Ry + // R1) in which the anode fault resistance (Rf +) is synthesized in parallel (S410).

Thereafter, the insulation resistance measuring apparatus 100 calculates the anode fault resistance Rf + (S412).

Then, the insulation resistance measuring apparatus 100 confirms whether the insulation between the battery Vb and the chassis ground is dielectric breakdown (S414).

If it is determined in step S414 that the insulation breakdown occurs, the insulation resistance measuring apparatus 100 turns off the first and second switches SW1 and SW2 (S416).

On the other hand, if it is determined that the insulation breakdown is not detected (S414), the insulation resistance measuring apparatus 100 turns off the third switch SW3 and turns on the fourth switch SW4 (S418).

Thereafter, the insulation resistance measuring apparatus 100 measures the capacitor voltage Vcap caught by the measurement capacitor Cm (S420). When the third and fourth switches SW3 and SW4 are turned off and turned on respectively, the voltage across the measured measuring capacitor Cm has the same value as the voltage across the anode common resistance Ry +.

Next, the insulation resistance measuring apparatus 100 measures the battery voltage Vb through the voltage measuring circuit 110 (S422).

Then, the insulation resistance measuring apparatus 100 calculates a combined resistance Rf - // Ry - // R2 in which the cathode fault resistance Rf- is synthesized in parallel (S424).

Thereafter, the measuring device calculates the negative electrode breakdown resistance Rf- from the calculated combined resistance Rf - // Ry - // R2 (S426).

Next, the insulation resistance measuring apparatus 100 confirms whether the insulation between the battery Vb and the chassis ground is insulation breakdown (S428).

In the case of insulation breakdown (S428), the insulation resistance measuring apparatus 100 turns off the first and second switches SW1 and SW2 (S430).

On the other hand, if it is determined that the insulation breakdown is not detected (S428), the insulation resistance measuring apparatus 100 determines that the insulation resistance of the battery Vb is not insulation breakdown and terminates the insulation resistance measurement process.

It will be understood by those skilled in the art that the present specification may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present specification is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the present specification Should be interpreted.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is not intended to limit the scope of the specification. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100: Insulation resistance measuring device
110: Voltage measurement circuit
120:
R1 and R2: first and second resistors
Cm: Measuring capacitor
SW1 to SW4: First to fourth switches
Ry + And Ry-: anode and cathode common resistance
Rf + And Rf-: anode and cathode fault resistance

Claims (11)

A first resistor connected in series to the battery, a measurement capacitor and a second resistor;
First and second switches connecting or disconnecting the line between the battery and the first resistor and the second resistor;
A third switch having one side connected between the first resistor and the measuring capacitor and the other side connected to the chassis ground of the vehicle;
A fourth switch having one side connected between the measuring capacitor and the second resistor and the other side connected to the third switch and the ground;
One and the other common resistors connected in parallel with the first resistor and the second resistor, respectively;
A voltage measuring circuit connected at both ends to the measuring capacitor to measure a capacitor voltage; And
When the one side resistance connected in parallel with the one common resistance is generated, the third or fourth switch is alternately turned on, and the one side resistance, the one side common resistance, A control unit for controlling the first and second switches according to whether the insulation resistance is broken due to one side fault resistance,
And an insulation resistance measuring device. The method according to claim 1,
The control unit
When a positive polarity breakdown resistance connected in parallel with the positive common resistance is generated between the positive terminal of the battery and the first resistance, the third and fourth switches are turned on and off, respectively, Wherein the anode breakdown resistance is calculated using the voltage across the common cathode resistor and the measured capacitor voltage. The method according to claim 1,
The control unit
When a cathode fault resistance connected in parallel with the cathode common resistance occurs between the anode terminal and the second resistance of the battery, the third and fourth switches are turned off and on, respectively, Wherein the negative terminal resistance is calculated by using the voltage across the positive common resistance divided by the voltage proportional to the voltage and the measured capacitor voltage. The method according to claim 1,
Wherein when the control unit turns on and off the third and fourth switches, the voltage across the measured measuring capacitor has the same value as the voltage across the common cathode resistance. The method according to claim 1,
And the voltage across the measured measuring capacitor has the same value as the voltage across the common anode resistance when the control unit turns off and on the third and fourth switches, respectively. A method of measuring an insulation resistance in an insulation resistance measuring apparatus including a first resistor connected in series to a battery, a measurement capacitor, and a second resistor,
Connecting a first resistor, a measurement capacitor and a second resistor in series to the battery;
A third switch having one side connected between the first resistor and the measuring capacitor and the other side connected to the chassis ground of the vehicle, and a second switch having one side connected between the measuring capacitor and the second resistor and the other side connected to the third switch and the ground Measuring a capacitor voltage by alternately turning on and off a fourth switch to be connected;
Side resistor and the first resistor are connected in parallel by using the measured capacitor voltage and the battery voltage when the one side resistance connected in parallel with the one common resistor connected in parallel with the first resistor is generated Calculating a resulting composite resistance; And
Calculating a one-side common resistance from the calculated composite resistance and a one-side fault resistance connected in parallel with the first resistance
Wherein the insulation resistance measuring method comprises the steps of: The method according to claim 6,
Determining whether the breakdown is an insulation breakdown according to the calculated breakdown resistance, maintaining the connection of the first and second switches if the breakdown is not caused according to the determination result, and blocking the first and second switches if the breakdown is insulation
Further comprising the steps of: The method according to claim 6,
The step of calculating the one-side fault resistance
When a positive polarity breakdown resistance connected in parallel with the positive common resistance is generated between the positive terminal of the battery and the first resistance, the third and fourth switches are turned on and off, respectively, Wherein the anode breakdown resistance is calculated using a voltage across the common cathode resistor and a measured capacitor voltage, the voltage being proportional to the anode current. The method according to claim 6,
The step of calculating the one-side fault resistance
When a cathode fault resistance connected in parallel with the cathode common resistance occurs between the anode terminal and the second resistance of the battery, the third and fourth switches are turned off and on, respectively, Wherein the negative terminal resistance is calculated using the voltage across the positive common resistor and the measured capacitor voltage. The method according to claim 6,
Wherein the measured voltage across the measured capacitor has the same value as the voltage across the common cathode resistance when the third and fourth switches are turned ON and OFF, respectively. The method according to claim 6,
Wherein when the third and fourth switches are turned OFF and ON respectively, the voltage across the measured measuring capacitor has the same value as the voltage across the anode common resistance.

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