JP6270564B2 - Method for detecting battery detachment in battery charger and battery charger therefor - Google Patents

Description

  The present invention relates to a method for detecting battery detachment in a battery charging device and the battery charging device, and more particularly, from a magnetic AC generator attached to a rotating shaft of an internal combustion engine of a farm machine such as a combine and a tractor or a vehicle such as a motorcycle. The present invention relates to a battery detachment detection method in a battery charger that charges a battery based on the power of the battery.

  Agricultural machines such as combines and tractors driven by internal combustion engines and vehicles such as two-wheeled vehicles usually have a rechargeable battery for supplying power to electrically operated devices. Charging generally uses the movement of a rotating mechanism driven by the internal combustion engine. Patent Document 1 discloses a charging device for charging such a battery.

  In Patent Document 1, as a basic configuration of a battery charging device, a magnet type AC generator (1) that is driven by an internal combustion engine mounted on a vehicle to generate an AC voltage, a diode (Du, Dv, Dw, and Dx, Dy, Dz) are connected by a three-phase bridge connection, the input terminals (2u, 2v, 2w) are connected to the output terminals (1u, 1v, 1w) of the generator (1), and the DC output terminals ( 2p, 2n), the rectifier circuit (2) connected to the battery (3), and the terminal voltage of the battery (3) is detected, and when the instantaneous value of the detected terminal voltage exceeds the set value, the overvoltage An overvoltage detection circuit (6) for generating a detection signal, each cathode is connected in common to the output terminal (2n) on the negative side of the rectification circuit (2), and each anode is an input terminal (2u, 2) of the rectification circuit (2) 2v, 2w) The thyristors (Thw, Thv, Thw) as output short-circuit switch elements and the gates of the respective thyristors (Thw, Thv, Thw) according to the overvoltage detection signal from the overvoltage detection circuit (6). And a switch element trigger circuit (7) for providing a trigger signal. With such a configuration, when the instantaneous value of the terminal voltage of the battery (3) becomes equal to or higher than the set value defined by the overvoltage detection circuit (6), the output terminals of the generator 1 are short-circuited, thereby causing a rectifier circuit. Since the supply of the charging current from (2) to the battery (3) is stopped, the terminal voltage of the battery (3) can be adjusted so as not to exceed the set value.

  In addition, in the battery charging device disclosed in Patent Document 1, the ripple voltage included in the DC voltage applied to the battery (3), which is compared with the set value, is the rotational speed of the generator (1), etc. In order to solve the problem of being affected by the operating state of the generator, the winding specifications of the generator (1), the capacity of the battery (3), the type of the load (4), etc., the battery ( The average value of the terminal voltage of 3) is detected by the resistors (R3 and R4), the capacitor (C1), and the A / D converter (11), and compared with the detected average value, the set value (first The second setting value lower than the setting value is provided, and when the average value exceeds the second setting value, a trigger signal is given to the gate of each thyristor (Thw, Thv, Thw) (CPU (13) and Transis (TR2)) is provided (paragraphs [0038] to [0044]), the load (4) is connected, and power is supplied from the generator (1) to the load (4). Charging current supply on / off based on the set value is made to function.

  Moreover, in the battery charging device disclosed in Patent Document 1, as a supplementary feature, even if there is a variation in the peak value of the half wave of the AC output of the generator (1), it is based on the second set value. In order for the charging current supply on / off function to function normally, the CPU (13) is preferably configured to output an on command signal having a frequency sufficiently higher than the output frequency of the generator (1). (Paragraphs [0060] to [0064]). Further, when the internal combustion engine is in an acceleration state, the second set value is increased so as to prevent the charging current supply from being turned off. On the other hand, when the internal combustion engine is in a deceleration state, the second set value is set. It is said that it is preferable to configure in such a direction that the charging current supply is turned off and promoted to turn off (paragraphs [0046] to [0051]). Further, when the temperature of the lubricating oil of the internal combustion engine exceeds a predetermined value, it is preferable to increase the second set value (paragraphs [0052] and [0053]). Further, it is preferable that the second set value is increased when the ambient temperature of the battery (3) is low, and the second set value is decreased when the ambient temperature is high (paragraph [0054], [0055]).

JP 2001-231180 A

  By the way, in the battery charging apparatus as disclosed in Patent Document 1, there is sometimes an unfavorable situation in which the battery is disconnected for some reason even when driving of the internal combustion engine is started. Such a situation can occur particularly when the vehicle is mounted on a motorcycle. Even in the case of such battery detachment, it can be basically determined by detecting the charge overvoltage as described above in the driving state.

  However, in a situation where many loads are connected, such a detection function does not work well. This is because the charging voltage does not rise to the set voltage for detecting the overvoltage even though a large amount of current flows through the load and the battery is disconnected. In addition, the pulsation may occur at a voltage lower than the set voltage for detecting overvoltage, which adversely affects those loads. Thus, when many loads are connected, there is a problem that not only battery disconnection cannot be detected but also the connected load is damaged due to generation of dangerous voltage outside the standard. there were.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a battery charging device for charging a battery based on electric power from a magnetic AC generator driven by an internal combustion engine. Even if the battery is disconnected without being detected, it is possible to accurately detect the internal combustion engine even in the driving state, and to protect the connected load from a dangerous voltage, and such a battery. The object is to provide a charging device.

  In order to achieve the above object, a battery detachment detection method according to the present invention is a battery charging device that charges a battery based on electric power from a magnetic AC generator driven by an internal combustion engine. The power supply to the battery from the magnet-type AC generator is forcibly stopped for a predetermined period periodically, and the battery is connected to the battery based on the terminal voltage attenuation characteristics within the predetermined period. The gist is to detect whether or not the battery charger is disconnected.

  Here, specifically, when the terminal voltage of the battery is attenuated by a predetermined voltage or more from the voltage at the start of the predetermined period before the predetermined period elapses, the battery is connected to the battery charging device. It is preferable to determine that it is out of the range.

  Alternatively, it is preferable to determine that the battery is disconnected from the battery charging device when the terminal voltage of the battery reaches a predetermined lower limit voltage before the predetermined period elapses.

  The predetermined period can be variably set. Further, it is preferable that each step is made effective when the internal combustion engine has a predetermined rotational speed or more.

  In order to achieve the above object, the battery charging device of the present invention is based on a battery to be charged, a magnet type AC generator driven by an internal combustion engine, and an AC voltage generated by the magnet type AC generator. A rectifier circuit for generating a direct current to be supplied to the battery, and when the terminal voltage of the battery reaches a predetermined voltage, the charging current from the rectifier circuit to the battery is interrupted to cut off the battery. A charging stop circuit for stopping charging and a terminal voltage of the battery are sequentially input, and in a driving state of the internal combustion engine, charging of the battery is forcibly stopped for a predetermined period periodically. A predetermined signal is output to the charge stop circuit, and the battery is disconnected based on the attenuation characteristics of the terminal voltage within the predetermined period. A microcomputer for detecting whether or not, and summarized in that comprises a.

  At this time, the microcomputer typically performs the acquisition of the terminal voltage, the setting of the predetermined period, the output of the predetermined signal, and the detection by a program that is periodically executed.

  According to the battery detachment detection method and its battery charging apparatus in the battery charging apparatus of the present invention, in the battery charging apparatus for charging the battery based on the electric power from the magnet type AC generator driven by the internal combustion engine, Even when the battery is disconnected, it can be accurately detected even in the driving state of the internal combustion engine, and the connected load can be protected from a dangerous voltage.

It is a block diagram which shows the structure of one Embodiment in the battery charging device of this invention. It is a flowchart which shows the process sequence of the microcomputer 37 in one Embodiment of the battery removal detection method of this invention. 5 is a flowchart showing details of a processing procedure of the microcomputer 37. It is a figure which shows the time transition of battery voltage moving average value VVA. It is a figure for demonstrating the reference | standard for determining battery detachment.

  The inventor of the present invention searches for a method for detecting battery disconnection in the driving state of the internal combustion engine, and when the supply of charging current is forcibly stopped, the battery is normal in the attenuation characteristic of the battery voltage thereafter. It was found that there is a difference between the case where the battery is connected and the case where the battery is disconnected, and that the battery disconnection can be detected accurately by sequentially examining the attenuation characteristics in the driving state.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an embodiment of a battery charging device according to the present invention. The battery charging device shown in FIG. 1 generally includes a battery 1 that is repeatedly charged and discharged according to the driving state of an internal combustion engine (not shown) on which a vehicle is mounted and power supply to a load (not shown), and an internal combustion engine. A magnetic AC generator 2 that is driven by an engine to generate a three-phase AC voltage, and plays a central role in controlling charging of the battery 1 based on the AC voltage from the magnet AC generator 2, and the battery 1 is disconnected. Whether or not to supply the electric power for generating the necessary 5V voltage in the charge control circuit unit 3 while switching the operation / stop of the internal combustion engine and the charge control circuit unit 3 for performing detection control of whether or not And a key switch 4 for switching between them.

  Here, in detail, the charge control circuit unit 3 includes a rectifier circuit 31 having the same configuration and function as the rectifier circuit (2) disclosed in Patent Document 1, and an overvoltage detection circuit (6) disclosed in Patent Document 1. The overvoltage detection circuit 32 having the same configuration and function, and the same configuration and function as the switch element trigger circuit (7) of Patent Document 1, and a signal from the overvoltage detection circuit 32 and a microcomputer 37 to be described later A charge stop trigger signal generation circuit 33 that generates a charge stop trigger signal based on the periodic forced stop signal HS, and a voltage adjustment circuit having the same configuration and function as the thyristor group (Thu, Thv, THw) of Patent Document 1 34, a pulse generation circuit 35 that outputs four pulses each time the magnet type AC generator 2 makes one rotation based on the rectified output waveform change of the rectifier circuit 31, and the battery 1 A rectangular voltage that can be input by a tachometer (not shown) connected to the voltage conversion circuit 36 for converting the child voltage into a range that can be captured by the microcomputer 37 (to be described later), the microcomputer 37 described in detail later, and the charge control circuit unit 3. A waveform shaping circuit 38 for forming a waveform, a driver circuit 39 for generating a signal capable of driving a charge lamp (not shown) connected to the charge control circuit unit 3, and supplied from the battery 1 via the key switch 4. And a 5V standard voltage generation circuit 40 that generates a standard voltage of 5V based on the generated power.

  Here, the rectifier circuit 31 charges the battery 1 by converting the three-phase AC voltage from the magnetic AC generator 2 into a DC voltage and supplying a charging current to the battery 1. The overvoltage detection circuit 32 detects the terminal voltage of the battery 1 and outputs an overvoltage detection signal to the charge stop trigger signal generation circuit 33 when the instantaneous value of the detected terminal voltage exceeds a predetermined set value. When the charge stop trigger signal generation circuit 33 receives the overvoltage detection signal from the overvoltage detection circuit 32, the charge stop trigger signal generation circuit 33 gives a trigger signal for turning on each thyristor constituting the voltage adjustment circuit 34, whereby each output terminal of the magnet type AC generator 2. Since the gap is short-circuited, the supply of the charging current to the battery 1 is stopped, and the terminal voltage of the battery 1 is suppressed to a predetermined value or less.

  In particular, the converted voltage obtained by converting the terminal voltage of the battery 1 into a voltage range that can be input to the microcomputer 37 by the voltage conversion circuit 36 is input to the first input port IN 1 of the microcomputer 37. The microcomputer 37 has therein an analog / digital (A / D) converter (not shown) that inputs the converted voltage, quantizes it every predetermined time, and samples it as a digital value. The predetermined time is, for example, 1 millisecond. Then, for example, a CPU (Central Processing Unit, not shown) of the microcomputer 37, every time a digital voltage value is output from the A / D converter, an average value (hereinafter referred to as “the following”, for example, four digital voltage values). Battery voltage moving average value VVA ") and obtained as an index of the terminal voltage of the battery 1. The average of the four latest digital voltage values can be obtained, for example, by preparing four storage variables and sequentially shifting the digital voltage values by a so-called FIFO method. Here, the reason why the predetermined number of average values is taken is to absorb error fluctuations (high frequency components). The predetermined time “1 ms” and the average number “4” are merely examples, and may be set to a preferable value as appropriate.

  On the other hand, the microcomputer 37 forces a charging operation to the battery 1 for a predetermined time (hereinafter referred to as “battery removal determination period TP”) every predetermined cycle (hereinafter referred to as “battery removal determination execution period EC”). The peripheral circuit is controlled to stop automatically. The battery detachment determination process execution cycle EC and the battery detachment determination period TP can be realized by the microcomputer 37 setting and counting each counter. Therefore, as a method for forcibly stopping the charging operation in the battery detachment determination period TP, as shown in FIG. 1, the charging stop trigger signal generation circuit 33 is supplied from, for example, the third output port OUT3 of the microcomputer 37 during that period. Thus, a signal equivalent to the overvoltage detection signal output by the overvoltage detection circuit 32 (hereinafter referred to as “periodic forced stop signal HS”) may be output.

  Accordingly, FIG. 4 shows a temporal transition of the battery voltage moving average value VVA when the battery detachment determination period TP is provided for each battery detachment determination process execution cycle EC. Since the charging operation is stopped during the battery detachment determination period TP, the battery voltage moving average value VVA exhibits a decreasing curve as shown in FIG. Here, when the battery 1 is detached, the inventor of the present invention has a large degree of the attenuation (in the figure, TP2 is a determination period when the battery 1 is detached). It has been found that if the degree is verified with an appropriate threshold, it can be determined whether or not the battery 1 is detached.

  Here, when battery detachment occurs, the terminal voltage of the battery 1 exhibits a phenomenon in which the terminal voltage fluctuates within a range that does not reach a predetermined set value (overvoltage determination voltage) set by the overvoltage detection circuit 32. Therefore, the battery voltage moving average value VVA in the microcomputer 37 also has a wobbling waveform as shown in FIG. 4 after the battery is disconnected. By the way, the start of the battery detachment determination period TP is irrelevant to the period and value of the fluctuation, and therefore, the attenuation of the battery voltage moving average value VVA starts with a high value of the fluctuation or conversely with a low value. It begins or is mixed. Therefore, in the embodiment of the present invention, as a reference for determining that the battery 1 is detached on the basis of the degree of attenuation of the battery voltage moving average value VVA, the following two are considered in consideration of variations in voltage at the start of the decrease. The standard was adopted.

  That is, the first is to cope with a case where the decay of the battery voltage moving average value VVA due to the start of the battery detachment determination period TP starts from a relatively high value. In this case, as shown in FIG. 5A, when the battery voltage moving average value VVA at the start of the battery detachment determination period TP is set to the period start voltage SV, before the battery detachment determination period TP ends. When the battery voltage moving average value VVA is attenuated by a predetermined amount (hereinafter referred to as “attenuation amount determination voltage ACV”) from the period start voltage SV, it is determined that the battery 1 is disconnected. In the figure, at time t1 before the end of the battery detachment determination period TP, the attenuation amount determination voltage ACV has already been attenuated.

  A second countermeasure is to deal with a case where the decay of the battery voltage moving average value VVA due to the start of the battery detachment determination period TP starts from a relatively low value. In this case, as shown in FIG. 5B, the battery voltage moving average value VVA has a predetermined lower limit value (hereinafter referred to as “lower limit determination voltage LCV”) before the battery removal determination period TP ends. Is reached, it is determined that the battery 1 is disconnected. When the attenuation of the battery voltage moving average value VVA starts from a relatively low value, there is a possibility that each control circuit may fall below the limit voltage at which each control circuit operates normally before it is attenuated by the attenuation amount determination voltage ACV. Accordingly, in this case, the lower limit determination voltage LCV is set as a voltage slightly higher than the limit voltage at which each control circuit operates normally, and if the lower limit determination voltage LCV is reached before the battery removal determination period TP ends. Make sure that the battery is disconnected. This figure shows that the lower limit determination voltage LCV has already been reached at time t2 before the end of the battery detachment determination period TP.

  From the above viewpoint, the criteria for setting the attenuation determination voltage ACV, the lower limit determination voltage LCV, and the battery removal determination period TP will be described next. Therefore, the degree of fluctuation of the above-described fluctuation phenomenon of the battery voltage moving average value VVA seen after occurrence of battery detachment, that is, the amplitude, depends on the capacity connected to the load (hereinafter referred to as “capacitive load”). Specifically, the amplitude is large when the capacitive load is small, and the amplitude is small when the capacitive load is large. Therefore, the degree of attenuation when entering the battery detachment determination period TP while the battery 1 is disconnected increases when the capacity load is small, and conversely decreases when the capacity load is large.

  Here, the larger the load capacity is, the smaller the attenuation amount is. Therefore, the possibility of attenuation by the attenuation amount determination voltage ACV is reduced within the battery detachment determination period TP. That is, there is a high possibility that the battery disconnection cannot be normally detected even though the battery 1 is disconnected. On the other hand, if the battery detachment determination period TP is lengthened in consideration of this, the charging ability as a normal battery charger (proportional to the battery detachment determination period TP / battery detachment determination process execution cycle EC) stops charging. Because the period becomes longer, it falls off accordingly. Furthermore, if the battery disconnection determination process execution cycle EC is lengthened, the charging ability can be prevented from being lowered by extending the battery disconnection determination process execution period EC. The time until the disconnection can be detected becomes longer, the unstable state becomes longer, and the influence on the system is increased accordingly. From the above, it is preferable that the attenuation amount determination voltage ACV and the battery detachment determination period TP are determined from the test results in consideration of the load capacity assumed in each vehicle (system). Further, as described above, the lower limit determination voltage LCV is set to a voltage slightly higher than the limit voltage at which each control circuit operates normally.

  As described above, although depending on each vehicle (system), as a typical value, the battery detachment determination process execution cycle EC is 2 seconds and the battery detachment determination period TP20 msec. The period TP / battery removal determination process execution cycle EC is 1%.

  Next, in the present embodiment of the present invention, the microcomputer 37 performs the periodic operation as described above when the rotational speed of the internal combustion engine is equal to or higher than a predetermined rotational speed (hereinafter referred to as “effective rotational speed”). A battery detachment determination process is performed with a battery detachment determination period TP. Therefore, as described above, the microcomputer 37 receives a pulse train corresponding to one rotation of the magnet type AC generator 2 with four pulses from the pulse generation circuit 35 at the second input port IN2, and the time interval between these pulses. From this, the rotational speed of the magnet type AC generator 2 is calculated, and further multiplied by a certain ratio (reduction ratio when the magnet type AC generator 2 is driven) is obtained as the rotational speed of the engine. The information on the rotational speed of the engine is sequentially output from the first output port OUT1, sent to the tachometer via the waveform shaping circuit 38, and displayed as the rotational speed of the engine.

  Here, as described above, the battery detachment determination process is made effective only when the rotational speed of the internal combustion engine is equal to or higher than the effective rotational speed for the following reason. That is, when the engine has a sufficient rotation speed, in other words, when the power generation capacity of the magnetic AC generator 2 is sufficiently effective, and the battery is disconnected, the output of the magnet AC generator 2 and the load This is because the consumed power is balanced, and a staggered voltage is applied to the load, so that it is necessary to avoid such a situation. Conversely, when the engine is stopped or unstable, it is necessary to protect the detection of battery disconnection.

  Further, as shown in FIG. 1, the microcomputer 37 additionally sends a signal indicating the state via the driver circuit 39 to the charge lamp for indicating whether or not the battery 1 is being charged. Supply.

  FIG. 2 is a flowchart showing a processing procedure of the microcomputer 37 in one embodiment of the battery detachment detecting method of the present invention, and FIG. Hereinafter, the processing procedure will be described in order with reference to FIGS. 4 and 5 along the flowcharts shown in the drawings.

  The process of the microcomputer 37 shown in FIG. 2 is a process that is periodically executed by using, for example, a timer interrupt. Therefore, first, it is determined whether or not the battery is determined to be detached (step S1). If it is already determined that the battery has been removed at that time (Yes in step S1), the following battery detachment detection control process does not need to be performed and the process immediately returns. On the other hand, if it is not determined that the battery is disconnected at that time (negative determination in step S1), the process proceeds to step S2, and it is determined whether or not the rotational speed of the internal combustion engine at that time is equal to or higher than the effective rotational speed. To do. If it is determined that the rotational speed of the engine is not equal to or higher than the effective rotational speed (negative determination in step S2), the control data is initialized and returned in step S3. On the other hand, when it is determined that the rotational speed of the engine is equal to or higher than the effective rotational speed (positive determination in step S2), the process proceeds to step S4. The method for detecting the engine rotational speed by the microcomputer 37 is as described above. When the engine rotational speed is equal to or higher than the effective rotational speed, the reason for making the following battery removal detection control process effective is also described above. Street.

  In step S4, the cycle counter for defining the battery detachment determination process execution cycle EC is updated (for example, +1). Then, at that time, it is determined whether or not one cycle of the battery detachment determination process execution cycle EC has been completed (step S5). This can be determined by whether or not the period counter has reached a predetermined value. From another viewpoint, the cycle counter is updated in step S4 each time the battery detachment detection control process is executed. Therefore, the length of the battery detachment determination process execution cycle EC is set by the variable setting of the predetermined value. This can be variably set.

  Therefore, when it is determined in step S5 that one cycle of the battery detachment determination process execution cycle EC has been completed (positive determination, see FIG. 4), in other words, the current time is a new battery detachment determination process execution cycle EC. If it is determined that the start point is the start point, a battery detachment determination period start process in step S6 is performed. The detailed procedure of the battery detachment determination period start process is shown in FIG. Referring to the figure, in the battery detachment determination period start process, first, the period counter is initialized (for example, cleared to 0) (step S61). Next, the battery voltage moving average value VVA at that time is stored and saved as the period start voltage SV (step S62). Next, a flag for indicating that the battery removal determination period TP is in progress is set (step S63), and the determination period counter is initialized (for example, cleared to 0) (step S64). Then, the charging of the battery 1 is stopped (step S65). As described above, the forced charge stop by the microcomputer 37 is performed by the microcomputer 37 outputting the periodic forced stop signal HS to the charge stop trigger signal generation circuit 33 from the third output port OUT3.

  On the other hand, if it is determined in step S5 that one cycle of the battery detachment determination process execution cycle EC has not ended, the process proceeds to step S7, and whether or not the time is within the battery detachment determination period TP. judge. This determination can be made by verifying whether or not the flag for indicating that the battery removal determination period TP is in progress is set. When it is determined that the current time is not within the battery detachment determination period TP (negative determination, see FIG. 4), the process returns as it is. On the other hand, when it is determined that the current time is within the battery detachment determination period TP (positive determination, see FIG. 4), the process proceeds to step S8.

  In step S8, the current (current) battery voltage moving average value VVA is detected. For this, what the microcomputer 37 calculates, for example, every 1 msec as described above may be taken in. Next, a voltage that is attenuated from the period start voltage SV is calculated by subtracting the detected current battery voltage moving average value VVA from the period start voltage SV stored at the start of the battery detachment determination period (step S9). Then, it is determined whether or not the voltage corresponding to the attenuation has reached the attenuation determination voltage ACV (step S10). When the attenuation voltage has reached the attenuation determination voltage ACV (affirmative determination, see FIG. 5A), the process proceeds to a process after battery removal detection in step S13. On the other hand, if the attenuation voltage has not yet reached the attenuation determination voltage ACV (negative determination), it is determined in step S11 whether or not the current battery voltage moving average value VVA has reached the lower limit determination voltage LCV. To do. When the current battery voltage moving average value VVA has reached the lower limit determination voltage LCV (affirmative determination, see FIG. 5B), the process proceeds to a process after battery detachment detection in step S13. On the other hand, when the current battery voltage moving average value VVA has not yet reached the lower limit determination voltage LCV (negative determination), the process proceeds to the battery detachment determination period end determination process in step S12.

  A detailed procedure of the battery detachment determination period end determination process in step S12 is shown in FIG. Referring to the figure, in the battery detachment determination period end determination process, first, the determination period counter is updated (for example, +1) (step S121). Then, at that time, it is determined whether or not the battery detachment determination period TP has ended (step S122). This can be determined by whether or not the determination period counter has reached a predetermined value. From another point of view, the determination period counter is updated in step S121 while it is within the battery detachment determination period TP in step S7 and no battery detachment is detected. Thus, the length of the battery detachment determination period TP can be variably set.

  Therefore, if it is determined in step S122 that the battery detachment determination period TP has not ended (No determination), the process directly returns. On the other hand, when it is determined that the battery detachment determination period TP has ended (affirmation determination, see FIG. 4), the above-described flag for indicating that the battery detachment determination period TP is in progress is then reset (step S123). Then, the charging of the battery 1 is resumed (step S124). This can be done by stopping the periodic forced stop signal HS output to the charge stop trigger signal generation circuit 33.

  On the other hand, FIG. 3C shows a detailed procedure of the processing after battery detachment detection in step S13. Referring to the figure, in the battery detachment determination post-process, first, the aforementioned flag for indicating that the battery detachment determination period TP is in effect is reset (step S131). Then, the charging of the battery 1 is completely stopped thereafter (step S132).

  As described above, according to the battery detachment detection method in the battery charger of the present invention and the embodiment of the battery charger, even if the battery 1 is unexpectedly removed, even when the internal combustion engine is driven, Can be accurately detected to protect the connected load from dangerous voltages.

  The battery detachment detection method of the present invention is a battery charging method for charging a battery based on electric power from a magnet type AC generator attached to a rotating shaft of an internal combustion engine of a farm machine such as a combine and a tractor or a vehicle such as a motorcycle. Can be used in equipment.

DESCRIPTION OF SYMBOLS 1 Battery 2 Magnet type AC generator 3 Charge control circuit part 31 Rectifier circuit 32 Overvoltage detection circuit 33 Charge stop trigger signal generation circuit HS Periodic forced stop signal 34 Voltage adjustment circuit 35 Pulse generation circuit 36 Voltage conversion circuit 37 Microcomputer 38 Waveform Shaping circuit 39 Driver circuit 40 5V standard voltage generation circuit 4 Key switch EC Battery detachment determination process execution cycle TP Battery detachment determination period ACV Attenuation amount determination voltage LCV Lower limit determination voltage

Claims (7)

In a battery charger for charging a battery based on electric power from a magnet type AC generator driven by an internal combustion engine,
In the driving state of the internal combustion engine, forcibly stopping the supply of power from the magnet type AC generator to the battery for a predetermined period,
A battery detachment detection method, comprising: detecting whether or not the battery is detached from the battery charging device based on an attenuation characteristic of a terminal voltage of the battery within the predetermined period.   When the terminal voltage of the battery is attenuated by a predetermined voltage or more from the voltage at the start of the predetermined period before the predetermined period elapses, it is determined that the battery is disconnected from the battery charging device. The battery detachment detecting method according to claim 1.   2. The battery according to claim 1, wherein when the terminal voltage of the battery reaches a predetermined lower limit voltage before the predetermined period elapses, it is determined that the battery is disconnected from the battery charging device. The method for detecting battery detachment as described.   4. The battery detachment detection method according to claim 1, wherein the predetermined period can be variably set.   5. The battery detachment detection method according to claim 1, wherein each step is validated when the internal combustion engine has a predetermined rotation speed or more. A battery to be charged,
A magnet type AC generator driven by an internal combustion engine;
A rectifier circuit that generates a direct current to be supplied to the battery based on an alternating voltage generated by the magnet type AC generator;
A charge stop circuit for cutting off the charging current from the rectifier circuit to the battery and stopping charging the battery when the terminal voltage of the battery reaches a predetermined voltage;
While sequentially inputting the terminal voltage of the battery, in a driving state of the internal combustion engine, a predetermined signal is sent to the charge stop circuit so as to forcibly stop charging the battery for a predetermined period. A microcomputer that outputs and detects whether or not the battery is disconnected based on the attenuation characteristics of the terminal voltage within the predetermined period;
A battery charging device comprising: 7. The microcomputer according to claim 6, wherein the microcomputer performs the acquisition of the terminal voltage, the setting of the predetermined period, the output of the predetermined signal, and the detection by a program that is periodically executed. Battery charger.

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