KR20080087705A - Device and detect method for battery impedance measuring - Google Patents

Abstract

An apparatus and a method for measuring internal resistance of a battery are provided to prevent a battery set from being affected by a measurement process by using a pulse signal simply generated by a switching circuit as a measurement signal. An apparatus for measuring internal resistance of a battery includes an exciting unit(1) and a measuring unit(2). The exciting unit outputs a pulse DC measurement signal having constant current effective value, duty cycle, and frequency to the battery. The measuring unit extracts a voltage feedback signal related to the constant duty cycle and frequency from output of the battery to calculate the inner resistance of the battery. The exciting unit has a pulse DC signal generating unit to output the pulse signal having the constant duty cycle and frequency and a DC power circuit to generate constant current having the constant effective value.

Description

Apparatus for measuring internal resistance of charging power supply and its measuring method {DEVICE AND DETECT METHOD FOR BATTERY IMPEDANCE MEASURING}

The present invention relates to an apparatus for measuring internal resistance of a charging power supply and a method of measuring the same.

Rechargeable power supplies are widely applied in various fields such as science and technology research, production, public life, transportation, etc., and can store chemical energy or other forms of energy stored in operation through physical, chemical and biological changes such as electrochemical reactions. It converts into electrical energy and, when charging, converts electrical energy into chemical energy or other forms of energy and stores it in the charging power supply. The most popular charging power supply is the battery.

Internal resistance is an important parameter that reflects the performance of the battery. Currently, there are two methods of measuring internal resistance of a battery: direct current measurement and alternating current measurement.

The direct current measuring method discharges a large current in a short time with respect to a storage battery, acquires the change of the end voltage at the time of discharge of a battery, and measures an internal resistance. In the DC measurement method, instantaneous large current discharge should be performed on the battery during the internal resistance measurement, so there is a defect that the safety of the measurement process is not high. If a battery with very low performance is present in the battery, a system error occurs easily when instantaneous large current discharge is performed on the battery using direct current measurement. In order to measure the internal resistance of the battery using the direct current measurement method, it must be performed in the static or offline state and cannot be measured in the operating state.

Conventional alternating current measurement provides a constant frequency alternating current signal to the battery while the battery acquires a voltage feedback signal for the alternating current signal to measure the alternating current impedance of the battery. The AC measuring method can solve the problem existing in the DC measuring method to some extent. However, in the internal resistance measurement by the AC method, the AC signal is injected into the battery. In the measurement process, the actual system performs cross-charging and discharging of the battery. In the process of performing this method, the measurement signal becomes an actual interference signal to the battery, thereby increasing the harmonics of the battery system. In addition, by injecting an AC signal directly into the battery system, the signal is susceptible to charging harmonics of a charging device connected to the battery system and affects measurement accuracy. It is also not easy to generate an AC constant current signal.

It is an object of the present invention to provide a measuring device capable of measuring internal resistance of a charging power supply device capable of obtaining precise measurement results using simply generated measurement signals.

Another object of the present invention is to provide a measuring method capable of measuring internal resistance of a charging power supply device capable of obtaining precise measurement results using a simply generated measurement signal.

The present invention provides an excitation unit for outputting a pulsed DC measurement signal having a constant current effective value, a duty cycle and a frequency to a charging power supply to be measured, and the constant duty cycle and frequency among the outputs of the charging power supply to be measured. It provides a measuring device for the internal resistance of the charging power supply device including a measurement unit for extracting a voltage feedback signal of interest and calculates the internal resistance of the charging power supply of the measurement object.

The present invention also provides a pulsed DC measurement signal having a constant duty cycle and frequency for a charging power supply to be measured, and a voltage output related to the duty cycle and frequency at an output voltage of the charging power supply to be measured. It provides a measuring method of a charging power supply device including acquiring a signal and calculating an internal resistance of the charging power supply of the measurement target.

Compared to a method of measuring the AC internal resistance of a battery using a conventional AC signal, the measuring device and the method provided by the present invention simply use a pulse signal that can be generated using a switching circuit as a measurement signal. In the measurement method, the defect that makes it difficult to generate an AC measurement signal can be overcome to avoid the effect of the measurement process on the battery set. At the same time, the inspection unit can more effectively output the effective feedback signal of the charging target power supply such as the accumulator, and the effect of the phase difference between the AC feedback signals of the charging power supply peaking up at different circulation orders during the cyclic measurement process can affect the measurement result. Effectively eliminated, the interference signal overlapping the charging power system of the charging device can be eliminated in the measurement process, and accurate measurement of the internal resistance of the charging power supply device can be realized. Accurate alternating current impedance of accumulators connected in series or used solely in a battery set by performing cross and unidirectional charging or discharging of the target battery under any use condition (charging, discharging, or offline). Measurement can be realized.

As used herein, the technical term "charging power supply" can be converted into chemical energy or other forms of energy and stored in the charging power supply at the time of charging through changes in physical, chemical and biological, etc. Refers to a power supply that can convert chemical or other forms of energy into electrical energy and output it. Representative of the charging power supply device is a storage battery, but is not limited to a storage battery. As used herein, the term "storage battery" refers to a battery in a broad range and includes lead-acid capacitors, nickel-cadmium batteries, lithium batteries, nickel-hydrogen batteries, lithium ion batteries and the like.

In the following detailed description to explain the principle of the present invention by the embodiment of the process of measuring the battery internal resistance, those skilled in the art using the present invention according to the contents disclosed herein the internal resistance of other types of charging power supply device It can be clearly understood that can be measured.

In the following, the present invention will be described in more detail with reference to the accompanying drawings and specific embodiments.

1 is a view showing the configuration of a measuring device of the internal resistance of the charging power supply device according to the present invention for measuring the internal resistance of the measurement battery set made by connecting a plurality of batteries in series. As can be seen in the figure, the measuring device includes an excitation part 1 and a measuring part 2, which are connected in parallel to both ends of a plurality of series-connected accumulators to be measured and pulsed with respect to the measuring battery set. Output DC measurement signal. The pulse direct current measurement signal has a constant duty cycle and frequency and a constant active current value.

The duty cycle and frequency of the pulsed DC measurement signal are selected according to the principles of power optimization and base wave frequency correlation. Too high a duty cycle and frequency will increase the effective value of the current at the same current peak value, increase the power consumption of the system during the measurement process, affect the accuracy of the measuring device and increase the cost of the system. If the duty cycle and frequency are too low, the amplitude of the feedback signal of the battery to the measurement signal can be reduced, increasing the difficulty of system measurement. For example, signals with frequencies of tens to hundreds of hertz (Hz) can be selected for lead-acid batteries, and signals with higher frequencies are used for other types of batteries such as nickel-hydrogen and nickel-cadmium. .

The selection of the effective current value of the pulsed DC measurement signal affects the amplitude of the feedback signal of the battery under measurement with respect to the measurement signal. If the effective current value is too large, the power consumption increases. If it is too small, the measurement difficulty of the feedback signal increases.

Those skilled in the art can understand that specific duty cycles and frequency and current effective values can be determined in a conventional manner for different specific measurement conditions and requirements based on the foregoing description.

In the specific embodiment shown in FIG. 1, the excitation section 1 is composed of a pulsed DC signal generating circuit and a DC power supply circuit, and both ends of the DC power supply circuit are respectively connected to both ends of the measurement battery set, and the pulsed DC signal The output terminal of the generation circuit is connected to the control terminal of the DC power supply circuit. In this embodiment, the pulse direct current signal generating circuit is a switching circuit and generates a pulse signal having a constant duty cycle and frequency. The DC power supply circuit generates a constant current having a constant effective value and outputs a pulse DC measurement signal having a constant duty cycle and frequency under the control of the pulse signal.

Those skilled in the art can use the configuration that can generate the pulse DC measurement signal by combining the pulse DC signal generation circuit and the DC power supply circuit to generate other pulse DC measurement signals as an excitation part of the present invention. Will understand clearly.

As shown in FIG. 1, the measuring unit 2 is connected in parallel to both ends of each of the batteries in the measurement capacitor set, receives the output of each battery, and extracts a signal related to the predetermined duty cycle and frequency therefrom. In the specific embodiment shown in Fig. 1, the measuring unit 2 includes a simulating circuit, a detection circuit (composed of a chop-wave circuit and a band pass filter circuit), an analog-digital conversion circuit, and a microprocessor (single unit). Chip microcomputer). The simulating circuit is connected to both ends of each battery, and the output terminal of the simulating circuit is connected to the input of the shock wave circuit, and the output of the shock wave circuit is connected to the input terminal of the band pass filter circuit, and the band pass filter circuit. The output terminal of is connected to the input terminal of the analog-to-digital conversion circuit, and the output terminal of the analog-to-digital conversion circuit is connected to the input terminal of the single chip microcomputer.

In the above embodiments, the digital processing is provided with a simplicity circuit, an analog-to-digital conversion circuit, and a single chip microcomputer. Single-chip microcomputers can be any type of microprocessor or computer, all that is needed is a computing function. Alternatively, analog signals can be used directly. In this case, a simple circuit, an analog-to-digital conversion circuit, and a single-chip microcomputer are not required. The pulsed DC measurement signal and the output from the measurement unit 2 output from the excitation unit 1 using a known method in the art. The required internal resistance signal can be obtained directly from the voltage signal.

Since the above-described configuration circuits can all use well-known techniques in the art, detailed descriptions of the structure and function thereof are omitted. However, it is well known to extract a signal having a desired duty cycle and frequency from the measured signals, and the above-described embodiments are intended to explain the purpose of the present invention, but not to limit the present invention. Since the main contents of the present invention are not to extract a signal, any circuit or device capable of processing a measurement signal and extracting a signal having a desired duty cycle and frequency may be used as the measurement unit of the present invention.

2 is a view showing the configuration of a measuring device for internal resistance of a charging power supply device according to the present invention for measuring internal resistance of a single storage battery. As shown, the configuration is similar to that of FIG. 1 except that the excitation section 1 and the measurement section 2 are connected in parallel between the positive electrode and the negative electrode of the battery, respectively.

1 and 2, in the method for measuring the internal resistance of the charging power supply apparatus of the present invention, a pulse signal having a constant duty cycle and frequency is generated through a pulse direct current signal generating circuit of the excitation unit 1 during actual measurement. And simultaneously control the DC power supply circuit of the excitation section 1 to generate a current signal having a constant effective value, and output a pulsed DC measurement signal using the harmony of the two signals to generate the storage battery (Fig. 2) or It is provided in the battery set (FIG. 1), and a current signal having a constant effective value is injected or extracted with respect to the measuring battery (or battery set).

According to a different pulse signal method, the measurement unit 2 uses a signal extraction method corresponding thereto. This signal is used to measure the characteristic impedance of the battery in relation to the pulse signal frequency. By using the measuring circuit's simplification circuit, it acquires the change of the voltage signal at the time of injecting or extracting a current signal having a constant effective value for each battery in the measuring battery, and also performs the wave-wave circuit, the band pass filter circuit and the analog-digital The conversion circuit effectively filters out the interference signal and scattering signal, and removes the dance signal which is too large in amplitude and the frequency excitation signal from the excitation signal generated at the base and the feedback signal related to the control signal frequency. The feedback signal is transmitted to a single chip computer for processing, and the battery AC impedance associated with the injection signal frequency is calculated.

According to another exemplary embodiment of the present invention, the excitation unit outputs a pulse DC measurement signal having a duty cycle and a frequency associated with each other, and extracts a signal related to the duty cycle and the frequency from the output of the battery or the battery set as the measurement unit, respectively. Based on these signals, the internal resistance of the battery or the battery set to be measured can be calculated to further improve the measurement accuracy of the internal resistance.

According to yet another embodiment of the present invention, in the case shown in FIG. 1, the battery set to be measured is divided into at least two sets, and each battery group includes at least one storage battery. In this embodiment, by using one or a plurality of excitation portions, a plurality of pulse direct current measurement signals having the same or different duty cycles and frequencies can be provided to each of the battery tanks to further improve the measurement accuracy of the internal resistance.

According to another embodiment of the present invention, the excitation unit generates a pulse direct current measurement signal and at the same time generates a control signal. The control signal includes a multiple of the frequency (1/3, 1/2, 1, N) of the characteristic impedance of the battery whose pulse generator has a certain duty cycle (typically 30% to 70%) and whose frequency is to be measured. That is, it can occur through the sending of a pulse signal (including the same frequency, division frequency and multiple frequency). When the signal level is 1, the connected battery is discharged or charged. When the signal level is 0, the discharge or charging is stopped.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above-described embodiments, which can be variously modified and modified by those skilled in the art to which the present invention pertains. Modifications are possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will belong to the scope of the present invention.

1 is a view showing the configuration of a measuring device of the internal resistance of the charging power supply device according to the present invention for measuring the internal resistance of the measurement battery set configured by connecting a plurality of batteries in series.

2 is a view showing the configuration of a measuring device for internal resistance of a charging power supply device according to the present invention for measuring internal resistance of a single storage battery.

Claims (10)

An excitation unit for outputting a pulsed DC measurement signal having a constant current effective value, a duty cycle, and a frequency to the charging power supply to be measured; And, A measurement unit configured to extract a voltage feedback signal related to the predetermined duty cycle and frequency from the output of the charging power supply of the measurement target and calculate an internal resistance of the charging power supply of the measurement target; Apparatus for measuring the internal resistance of the charging power supply characterized in that it comprises. The method of claim 1, wherein the excitation portion A pulse direct current signal generating circuit for outputting a pulse signal having the predetermined duty cycle and frequency; A DC power supply circuit which receives the output of the pulsed DC signal generating circuit and generates a constant current having a predetermined effective value, The output of the DC power supply circuit is a pulsed current measurement signal is provided to the charging power supply of the measurement target, characterized in that the charging power supply device internal resistance measuring device. The method of claim 1, wherein the measuring unit A simulating circuit for simulating the output voltage of the charging power supply of the measurement target; A detection circuit configured to receive a voltage simpling signal output from the simulating circuit and to detect the voltage simpling signal to extract a voltage signal associated with the predetermined duty cycle and frequency; An analog to digital conversion circuit for receiving a voltage signal output from the detection circuit and converting the voltage signal into a digital voltage signal; And A microprocessor for receiving the digital voltage signal and calculating an internal resistance of the charging power supply of the measurement target based on the pulsed DC signal of the excitation unit; Apparatus for measuring the internal resistance of the charging power supply characterized in that it comprises. The method of claim 3, The detection circuit is a measuring device for the internal resistance of the charging power supply, characterized in that it comprises a V-wave circuit and a band pass filter circuit. The method of claim 1, Wherein the excitation section outputs a plurality of pulsed direct current signals having a duty cycle and a frequency associated with each other. The method of claim 1, The measuring unit includes a plurality of input terminals, the measuring apparatus of the internal resistance of the charging power supply, characterized in that for receiving the output of each of the charging power supply of the set of the charging power supply of the measurement target consisting of a plurality of charging power supply. (a) providing a pulsed DC measurement signal having a predetermined duty cycle and frequency to the charging power supply to be measured; And (b) calculating an internal resistance of the charging power supply to be measured by acquiring a voltage output signal related to the duty cycle and the frequency from the output voltage of the charging power supply to be measured; Method of measuring the internal resistance of the charging power supply comprising a. The method of claim 7, wherein The charging power supply to be measured is a set of charging power supplies formed by connecting a plurality of charging power supplies in series. Before performing step (a), the charging power supply unit is divided into at least two sets. At least one charging power supply, And measuring a pulse direct current signal having a predetermined duty cycle and frequency for each charging power supply group in step (a). The method of claim 7, wherein In the step (a), the charging power supply unit has a predetermined duty cycle and generates a control signal which is a multiple of the characteristic impedance frequency of the internal resistance to be measured so as to control the charging power supply to proceed or stop discharging or charging. A method of measuring internal resistance of a charging power supply, characterized in that the cross-injection or extraction of a current signal having a constant effective value for the charging power supply is performed. The method of claim 7, wherein The charging power supply of the measurement target is a set of charging power supply is made by connecting a plurality of charging power supply in series, and extracting the voltage output signal related to the duty cycle and frequency from the output voltage of each charging power supply in step (b) Method for measuring the internal resistance of the charging power supply characterized in that for calculating the internal resistance of each charging power supply.

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