JP2016082840A - Battery charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a function for outputting a rotation detection signal including rotational speed information of an engine in a battery charger for charging a battery with output of a magnet type AC generator that is driven by the engine.SOLUTION: A battery charger comprises: a pulse signal generation circuit 203 for generating a pulse signal each time, when one of positive and negative half waves of an AC voltage outputted from the magnet type AC generator is defined as a detection object half wave, it is detected that a voltage of the detection object half wave reaches a preset detection value; an output voltage detection circuit 204 for detecting an output voltage of the generator; and rotation detection signal generation means 205C for generating the rotation detection signal of a pulse waveform including information about the rotational speed of the engine calculated from a generation interval of the pulse signals which are generated by the pulse signal generation circuit if the output voltage detected by the output voltage detection circuit exceeds a preset reference value.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a battery charging device that charges a battery by the output of a magnetic AC generator.

  In a machine equipped with an engine, for example, as shown in Patent Document 1, when a battery voltage does not reach a set reference value, a battery is output with an output of a magnet type AC generator driven by the engine. I try to charge it. Also, in a machine equipped with an engine, when it is necessary to display the rotation speed of the engine on a tachometer, as shown in Patent Document 2, a pulse is generated every time the crankshaft of the engine rotates by a certain angle. Is provided, and a signal for driving the tachometer is generated from the output of the crank angle sensor.

  However, in a small machine that requires simplification of configuration, such as an agricultural machine, the rotational speed of the engine is detected without using a crank angle sensor, and information on the detected rotational speed is included. It may be necessary to output the rotation detection signal to the outside in order to drive the tachometer or the like. Therefore, as shown in Patent Document 3, a dedicated detection coil for detecting the rotational speed is provided in the magnet type AC generator attached to the engine, and the positive half-wave output voltage of the detection coil is provided. Has been proposed to detect the engine rotation speed (rpm) from the time from when each detection operation is performed until the next detection operation is performed. .

  In the invention disclosed in Patent Document 3, when noise is included in the output voltage of the detection coil, there are a plurality of detection operations for detecting that the output voltage has reached the detection value during the half-wave period of the output voltage. In order to prevent erroneous detection of the rotation speed, the half-wave waveform of the output voltage of the detection coil is shaped into a continuous waveform in which the noise voltage and main voltage cannot be distinguished by charging and discharging the capacitor. A waveform shaping circuit is provided.

JP 2005-198426 A JP-A-5-52859 JP 2000-258445 A

  The output voltage of the alternator used to charge the battery preferably has a sinusoidal waveform, but the voltage waveform of the magnet type alternator includes the number of stator poles, the stator winding method, the rotor Due to various factors such as the number of poles, an ideal sine wave is often not obtained. As shown in FIG. 8A, the positive and negative half waves have a trapezoidal shape, or as shown in FIG. In the middle of the peak of the positive and negative half-waves, the central part of the peak is raised, or as shown in FIG. 5C, the central part of the peak is recessed and formed between the two peak parts. Or a waveform having two peaks with different peak values and one valley formed between the peaks as shown in FIG. Often.

  As shown in FIGS. 8 (C) and (D), when the generator outputs an alternating voltage that exhibits a waveform in which a plurality of peaks appear successively, a detection value in which the output voltage of the generator half-wave is set. When the detection speed is detected every time the engine reaches the value of the generator, and the rotation speed of the generator is determined from the time from when each detection action is performed until the next detection action is performed, In the process of increasing the output voltage, a state in which the detection operation is performed a plurality of times during the half-wave period of the output voltage may occur, and the rotational speed of the engine may be erroneously detected.

  In the invention disclosed in Patent Document 3, when the noise voltage is included in the output voltage of the detection coil for detecting the rotational speed provided in the generator, the detection operation is performed when the noise voltage reaches the detection value. In order to prevent erroneous detection of the rotation speed, a waveform shaping circuit is provided that shapes the noise voltage and the main voltage so as to form a continuous waveform. The circuit shapes the output signal of the dedicated detection coil for detecting the rotational speed, and has a circuit configuration for low current considering the combination with the detection coil. Then, since heat generation becomes large, it cannot be used by being connected to a generator that outputs a large current like a magnet type AC generator that charges a battery.

  An object of the present invention is to accurately detect the rotation speed from the output voltage of a magnet type AC generator that outputs a large current to charge a battery and output a rotation detection signal including information on the engine rotation speed to the outside. It is an object of the present invention to provide a battery charging device that can be used.

  The present invention includes a rectifier that rectifies the output of a magnetic AC generator driven by an engine and supplies the rectifier to a battery, and a battery charge control circuit that controls the rectifier so that the voltage across the battery is kept within a set range. Targeted battery chargers.

  The battery charging device according to the present invention has a detection value in which a half-wave voltage to be detected is set as a half-wave with one of the positive and negative half-waves of the AC voltage output from the generator as a detection target. A pulse signal generation circuit for generating a pulse signal each time it is detected, an output voltage detection circuit for detecting an output voltage of the generator, and an output voltage detected by the output voltage detection circuit exceeds a reference value Output voltage determining means for determining whether the output voltage is detected, and the pulse signal generating circuit is generated when the output voltage detecting means determines that the output voltage detected by the output voltage detecting circuit exceeds a reference value And a rotation detection signal generating means for generating a rotation detection signal including information on the rotation speed of the engine obtained from the pulse signal to be generated.

  If comprised as mentioned above, without attaching a rotation sensor to an engine, the rotation speed detection signal used in order to detect the rotation speed of an engine directly from the output of the magnet type AC generator for battery charging, and to operate a tachometer etc. Can be output externally.

  Further, as described above, if the rotation detection signal generating means is configured to output the rotation detection signal only when the output voltage detected by the output voltage detection circuit exceeds the set reference value, a plurality of rotation detection signal generating means are configured. When the generator outputs an alternating voltage that exhibits a waveform having a peak and at least one valley, rotation is detected during the half-wave period to be detected by setting the reference value to an appropriate value. Even if the output waveform of the generator exhibits various waveforms that deviate from the sine waveform, it is possible to prevent the engine rotation speed from being erroneously detected due to multiple occurrences of the signal. It is possible to generate a rotation detection signal in which is accurately reflected and to operate an external device such as a tachometer accurately.

  In one aspect of the present invention, each time the pulse signal generation circuit generates a pulse signal, the rotation detection signal generation means includes the latest n pulses (n is an integer of 3 or more) generated by the pulse signal generation circuit. An average value of time intervals between signals is calculated, and a rotation detection signal is generated at a time interval proportional to the calculated average value.

  If comprised in this way, the rotation detection signal in which the average value of the engine rotational speed was reflected can be obtained, without being influenced by the instantaneous fluctuation | variation of the engine rotational speed.

  When the magnet type AC generator is configured to output a multiphase AC voltage, the pulse signal generation circuit is configured to output one of the positive and negative half-waves of any one-phase AC voltage output from the generator. It is preferable that the half wave be a detection target half wave.

  Also, when the magnet type AC generator is configured to output a multiphase AC voltage, the output voltage detection circuit is configured to detect the average value of the half wave of the output voltage of all phases of the generator. Is preferred.

  In each of the above aspects, the reference value used for determining whether or not to output the rotation detection signal from the rotation detection signal generation unit is preferably set to be less than the lower limit value of the voltage setting range at both ends of the battery.

  In one aspect of the present invention, when the generator is configured such that a plurality of peaks and at least one valley appear in each half-wave waveform of the output voltage, the reference value is set to the battery voltage. When the trough that appears in the output voltage waveform after the half-wave voltage of the output voltage of the generator exceeds the detected value once does not fall below the detected value. The value is set to a value equal to or greater than the voltage value of the generator output voltage detected by the output voltage detection circuit.

  According to the present invention, the rotational speed of the engine can be directly calculated from the output of the magnet type AC generator used for charging the battery without attaching a rotation sensor or the like to the engine and without providing a dedicated detection coil in the generator. Rotation detection signals used to detect and operate external devices can be output to the outside, so that the engine rotation can be done without complicating the structure around the engine or the generator structure. A rotation detection signal including speed information can be provided to an external device (for example, a tachometer).

  In the present invention, an output voltage detection circuit for detecting the output voltage of the generator and an output voltage determination means for determining whether or not the output voltage detected by the output voltage detection circuit exceeds a reference value are provided. Since the rotation detection signal is output only when the output voltage detected by the output voltage detection circuit exceeds the reference value, the AC voltage exhibits a waveform in which a plurality of peaks and at least one valley appear. When the generator outputs, the reference value is set to an appropriate value, so that multiple rotation detection signals are generated during the half-wave period for which the output voltage of the generator is to be detected. It is possible to prevent a situation in which the rotation speed is erroneously detected. Therefore, even when the output voltage waveform of the generator exhibits various waveforms that deviate from the sine waveform, it always generates a rotation detection signal that accurately reflects the rotation speed of the engine and accurately operates external devices such as a tachometer. Can be made.

It is the block diagram which showed the whole structure of one Embodiment of this invention. FIG. 2 is a circuit diagram illustrating an example of a specific configuration of each unit illustrated in FIG. 1. It is the block diagram which showed the structure of the rotation detection signal generation part which the microcomputer implement | achieves in embodiment of this invention. It is a time chart for demonstrating operation | movement of embodiment of this invention. It is another time chart for demonstrating operation | movement of embodiment of this invention. It is another time chart for demonstrating operation | movement of embodiment of this invention. 2 is a time chart for explaining an operation in a case where a rotation detection signal is output unconditionally without determining the output voltage in the embodiment shown in FIG. 1. (A) thru | or (D) are the wave form diagrams which showed the various output voltage waveforms of the magnet type AC generator.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an overall configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a magnet rotor in which a permanent magnet is attached to a rotor yoke to form a field, and magnetic poles of the magnet rotor. It is a well-known magnet type AC generator provided with the stator comprised by winding an electric power generation coil around the armature core which has a magnetic pole part which opposes. The rotor of the generator 1 is attached to the crankshaft of the engine directly or via a transmission, and the stator is attached to an engine case or the like. The magnet type AC generator 1 used in the present embodiment has a UVW three-phase generator coil in its stator, and outputs a three-phase AC voltage having a frequency proportional to the rotational speed of the engine from the generator coil. .

  In FIG. 1, reference numeral 2 denotes a battery charging device that charges a battery by supplying a DC voltage obtained by rectifying the output of a magnet type AC generator driven by an engine to a battery 3. The battery charging device 2 includes AC input terminals 2u, 2v and 2w to which a three-phase AC voltage output from the magnet AC voltage 1 is input, and a positive output terminal connected to the positive terminal and the negative terminal of the battery 3, respectively. 2a, a negative output terminal 2b, a battery voltage input terminal 2c connected to the positive terminal of the battery 3 via the key switch 4, and a rotation detection signal output terminal 2d for outputting a rotation detection signal applied to the tachometer 5. doing.

  The battery charging device 2 keeps the voltage at both ends of the battery 3 within the set range, and the rectifier 201 that rectifies the three-phase AC voltage input to the input terminals 2u to 2w from the magnet type AC generator 1 driven by the engine. And a battery charge control circuit 202 for controlling the rectifier 201 as basic components.

  The rectifier 201 is composed of a rectifier circuit having a function of controlling an output voltage in accordance with a control signal given from the outside, for example, a rectifier circuit constituted by a mixed bridge circuit of a diode and a thyristor.

  The battery charge control circuit 202 detects the voltage (battery voltage) across the battery 3 and controls the rectifier circuit of the rectifier 201 so as to keep the detected battery voltage within a set range.

  As described above, the battery charging device 2 includes the rectifier 201 that rectifies the output of the magnet type AC generator 1 driven by the engine and supplies the rectifier to the battery, and the rectifier so as to keep the voltage across the battery 3 within the set range. The battery charging control circuit 202 that controls 201 is configured as a basic component, but in this embodiment, the battery charging device 2 has a function of outputting a rotation detection signal including information on the rotation speed of the engine to the outside. For this purpose, a pulse signal generation circuit 203, an output voltage detection circuit 204, a rotation detection signal generation unit 205, a power supply circuit 206, and a rotation detection signal output circuit 207 are further provided.

  The pulse signal generation circuit 203 is configured to detect one of the positive and negative half waves of the one-phase voltage Vu of the three-phase AC voltage output from the magnetic AC generator 1 as a half wave. Each time it is detected that the half-wave voltage reaches a set detection value, a pulse signal is generated.

  The output voltage detection circuit 204 is a circuit that detects the output voltage of the generator 1. In this embodiment, the output voltage detection circuit detects the average value of the half-waves of the output voltages of all phases of the generator 1. Configured as follows.

  The rotation detection signal generation unit 205 includes a microcomputer MC having input ports IN1 and IN2 and an output port OUT1, and pulses output from the pulse signal generation circuit 203 to the input ports IN1 and IN2 of the microcomputer, respectively. The signal and the output of the output voltage detection circuit 204 are input. The rotation detection signal generation unit 205 is an engine obtained from the generation interval of the pulse signal generated by the pulse signal generation circuit 203 when the output voltage of the generator detected by the output voltage detection circuit 204 exceeds the set reference value. A rotation detection signal Sr having a pulse waveform including information on the rotation speed is output from the output port OUT1 of the microcomputer MC.

  When the key switch 4 is closed, the power supply circuit 206 receives a voltage across the battery 3 as an input and outputs a constant DC power supply voltage (for example, 5 V) necessary for operating the microcomputer MC. The rotation detection signal output circuit 207 is composed of, for example, an amplifier circuit, and rotates the rotation detection signal Sr output from the output port OUT1 by the microcomputer as the rotation detection signal Sr ′ at a level necessary for driving an external load. Output from the detection signal output terminal 2d to the outside. The rotation detection signal Sr ′ can be supplied to an appropriate load that requires engine rotation speed information. In this embodiment, the rotation detection signal Sr ′ is supplied to the tachometer 5.

  Referring to FIG. 2, an example of a more specific configuration of each part of the configuration shown in FIG. 1 is shown. The magnetic AC generator 1 has three-phase power generation coils Au, Av, and Aw on its stator, and voltages Vu, Vv, and Vw generated in these power generation coils are input to the rectifier 201. In the rectifier 201 shown in FIG. 2, the upper side of the bridge is configured by thyristors Su, Sv, and Sw, and the lower side of the bridge is configured by diodes Du, Dv, and Dw connected in series to the thyristors Su, Sv, and Sw, respectively. It consists of a full-bridge rectifier circuit.

  In the illustrated rectifier 201, the connection points of the anodes of the thyristors Su, Sv, and Sw and the cathodes of the diodes Du, Dv, and Dw are connected to the AC input terminals 2u, 2v, and 2w, respectively, and the thyristors Su, Sv, and Sw The common connection point of the cathode and the common connection point of the anodes of the diodes Du, Dv, and Dw are connected to the positive output terminal 2a and the negative output terminal 2b, respectively. The gates of the thyristors Su, Sv, and Sw of the rectifier 201 are connected to gate signal output terminals 202 u, 202 v, and 202 w provided in the battery charge control circuit 202.

  The battery charge control circuit 202 detects the voltage across the battery 3 (battery voltage), and simultaneously applies a gate signal to the thyristors Su, Sv and Sw when the detected battery voltage falls below the lower limit value of the setting range. The supply of the gate signal to the thyristors Su, Sv and Sw is stopped when the detected battery voltage exceeds the upper limit of the setting range.

  When the battery voltage falls below the lower limit of the set voltage range and a gate signal is applied from the battery charge control circuit to the thyristors Su, Sv and Sw, a forward voltage is applied between the anode and cathode of the thyristors Su to Sw. The thyristor is turned on, and charging current is supplied from the generator 1 to the battery 3 through the rectifier 201. Further, when the supply of the gate signal from the battery charge control circuit 202 to the thyristors Su to Sw is stopped when the battery voltage exceeds the set upper limit of the voltage range, the thyristors Su to Sw have their anode potentials at the cathodes. On the other hand, when it becomes a negative potential and the anode current becomes less than the holding current, it is turned off and the supply of the charging current to the battery is stopped. With these operations, the battery voltage is kept within the set range.

  The pulse signal generation circuit 203 receives a one-phase AC voltage among the three-phase AC voltages output from the generator 1 as a half wave with one of the positive and negative half waves of the AC voltage as a detection target. Each time it is detected that the half-wave voltage to be detected has reached a set detection value, a pulse signal is generated. The pulse signal generation circuit 203 used in the present embodiment sets the half-wave voltage as a detection value in which the positive half-wave of the U-phase AC voltage Vu output from the generator 1 is a detection target. It is configured to generate a pulse signal when reached.

  The illustrated pulse signal generation circuit 203 includes an NPN transistor Tr1 whose emitter is grounded and a collector connected to the output terminal of the power supply circuit 206 through a resistor R1, a resistor R2 connected between the base and emitter of the transistor Tr1, and a transistor The first Zener diode ZD1 whose anode is connected to the base of Tr1 through the resistor R3, the second Zener diode ZD2 connected between the cathode of the Zener diode ZD1 and the ground, and one end of the cathode of the first Zener diode ZD1 Is connected to the U-phase input terminal 2u and the resistor R5 is connected to the collector of the transistor Tr1, and the collector voltage of the transistor Tr1 is detected through the resistor R5. Microprocessors constituting the signal generator 205 Is input to the input port IN1 of the processor.

  The U-phase AC voltage Vu output from the generator 1 is input to the illustrated pulse signal generation circuit 203, and when the positive half-wave voltage (FIG. 4A) of the AC voltage Vu reaches the detection value. The Zener voltage of the Zener diode ZD1 is set so that the Zener diode ZD1 becomes conductive. Therefore, when the positive half-wave voltage of the U-phase AC voltage Vu is less than the detection value, no base current is supplied to the transistor Tr1, so that the transistor Tr1 is in an off state and the collector potential is at a high level (5 V). It is in the state of. When the positive half-wave voltage of the U-phase AC voltage Vu reaches the detection value, the Zener diode ZD1 is turned on, so that a base current is applied to the transistor Tr1 and the transistor is turned on. It drops from 5V to almost 0V. Therefore, as shown in FIG. 4B, the collector of the transistor Tr1 maintains a high level during the period when the positive half-wave voltage of the AC voltage Vu is less than the detected value and during the negative half-wave period of the AC voltage Vu. Thus, a signal maintaining approximately 0 V is obtained during the period when the positive half-wave voltage of the AC voltage Vu is equal to or higher than the detection value.

  A change in the collector potential of the transistor Tr1 is input to the input port IN1 of the microcomputer MC through the resistor R5. A voltage signal input to the input port IN1 of the microcomputer MC is assumed to be Vin1. As shown in FIG. 3, the microcomputer MC recognizes the fall of the voltage signal Vin1 from the high level to the 0 level as a pulse signal, and each time the pulse signal is recognized, the pulse signal generation circuit 203 The pulse interval average value calculating means 205A for calculating the average value of the time interval between the output pulse signals and the output voltage of the generator detected by the output voltage detection circuit 204 are compared with the reference value, and the detected output An output voltage determination means 205B for prohibiting the output of the rotation detection signal when the voltage is equal to or lower than the reference value and allowing the output of the rotation detection signal when the detected output voltage exceeds the reference value; When the voltage determination means 205B permits the output of the rotation detection signal (when the output voltage of the generator exceeds the reference value), the pulse interval average value calculation means 205A It is programmed to configure a rotation detection signal generating means 205C for generating a rotation detection signal of the pulse waveform in the operation time interval in proportion to the pulse frequency than.

  The pulse interval average value calculation means 205A stores, for example, the time (pulse signal generation interval) from the time when the previous pulse signal is generated to the time when the current pulse signal is generated every time each pulse signal is generated. The average value (moving average value of the pulse signal generation intervals) of the most recent n stored pulse signals (n is an integer of 3 or more) is calculated. The rotation detection signal generation means 205C outputs a pulse waveform signal repeatedly generated at a time interval proportional to the calculated average value (including a time interval equal to the calculated average value) from the output port OUT1 as a rotation detection signal. .

  FIG. 5 shows an example of processing performed in the process in which the microcomputer MC calculates the average value of the pulse signal generation intervals and outputs the rotation detection signal. Each time the microcomputer detects the fall of the voltage signal Vin1 (FIG. 5A) input to the input port IN1 at times txa, txb,... (Each time it recognizes that a pulse signal has occurred) As shown in FIG. 5 (B), the time from the previous pulse signal generation time to the current pulse signal generation time is calculated as pulse signal generation intervals t1, t2, t3,. By storing the generation interval, integrating (adding) time interval data t1, t2,... Tn between the latest n pulse signals, and dividing the integrated value by the number of integrated data. The average value of the time intervals between the pulse signals is calculated and stored. The pulse interval average value calculation means 205A is configured by these processes.

  In the example shown in FIG. 5, every time each pulse signal is generated, as shown in FIGS. 5C and 5D, the time interval between the four latest pulse signals (pulse signal generation interval). And the integrated value is divided by 4 to calculate the average value of the time intervals between the pulse signals. For example, at time txe, as shown in FIG. 5C, by dividing the integrated value t1 + t2 + t3 + t4 of the data t1, t2,. An average value Te of the pulse signal generation intervals generated during the period txe is calculated, and at time txf, as shown in FIG. 5D, the integrated value of the pulse signal generation interval data t2, t3,. By dividing t2 + t3 + t4 + t5 by the number of data 4, the average value Tf of the generation intervals of the pulse signals generated during the period from time txb to txf is calculated. Similarly, at times txa to txd, average values Txa to Txd of the generation intervals of the latest n pulse signals are calculated. These average values are inversely proportional to the rotational speed of the engine.

  In the example shown in FIG. 2, the output voltage detection circuit 204 includes diodes D11 to D13 having anodes connected to the AC input terminals 2u to 2w through resistors R11 to R13 and cathodes connected in common, and diodes D11 to D13. A voltage dividing circuit composed of a series circuit of resistors R14 and R15 connected between the common connection point of the cathode and the ground, a diode D14 having an anode connected to the voltage dividing point of the voltage dividing circuit, and a cathode and a ground of the diode D14 The capacitor C1 is connected between the capacitor C1 and the Zener diode ZD3 connected in parallel with both ends of the capacitor C1 facing the ground side. The voltage at both ends of the capacitor C1 is input to the input port IN2 of the microcomputer. Yes. A voltage input to the input port IN2 of the microcomputer is Vin2.

  The illustrated output voltage detection circuit 204 outputs a voltage proportional to the average value Vav of the three-phase AC output voltages of the generator 1 to both ends of the capacitor C1. In the illustrated output voltage detection circuit 204, the average value of the output voltage of the generator 1 is set so that it can be determined whether or not the average value of the AC output voltage of the generator 1 has reached the reference value. The voltage dividing ratio of the voltage dividing circuit composed of the series circuit of the resistors R14 and R15 and the Zener voltage of the Zener diode ZD3 are set so that the Zener diode ZD3 is not conducted until the reference value is exceeded. The Zener diode ZD3 is provided to prevent an excessive voltage from being input to the input port IN2 of the microcomputer when the output voltage of the generator 1 rises.

  In the present embodiment, when the output voltage waveform of the generator 1 exhibits a waveform in which a plurality of peaks and at least one valley appear in each half wave, as shown in FIGS. In order to prevent a rotation detection signal from being generated a plurality of times during each half-wave period of the generator output voltage and erroneously detecting the rotation speed, an output voltage detection circuit 204 and an output voltage determination unit 205B are provided and output. The rotation detection signal is output from the rotation detection signal generating means 205C only when the output voltage of the generator detected by the voltage detection circuit exceeds the set reference value.

  As shown in FIG. 4C, the output voltage determination unit 205B compares the generator output voltage average value Vav detected from the voltage signal Vin2 input from the output voltage detection circuit 204 with a reference value, While the average value Vav of the output voltage is below the reference value, the output of the rotation detection signal is prohibited as shown in FIG. 4D, and the average value of the output voltage exceeds the reference value at time ty. Sometimes output of rotation detection signal is permitted.

  The rotation detection signal generation unit 205C sets the potential of the output port OUT1 to a high level at the timing of generating the rotation detection signal when the output voltage determination unit 205B permits the output of the rotation detection signal and averages the pulse intervals. The time k * Tav (k is a proportional constant determined by the number of rotation detection signals generated per engine revolution) proportional to the average value Tav of the latest pulse generation intervals calculated by the value calculation means 205A is generated. The interval Tint is calculated, and a timer in the microcomputer is started to measure the calculated generation interval Tint.

  The rotation detection signal generation means 205C also calculates the pulse width Tw = α * Tint / 100 of the rotation detection signal by multiplying the calculated generation interval Tint (= k * Tav) by a predetermined duty ratio α (%). The timer is then started to measure this pulse width Tw. When the timer completes the measurement of the pulse width, the potential of the output port OUT1 is lowered from 5V to 0V to make the rotation detection signal 0 level, and then the generation interval Tint at which the timer is set is completed. Further, the potential of the output port OUT1 of the microcomputer is set to a high level. As a result, as shown in FIG. 5E, a rotation detection signal Sr having a pulse waveform that repeatedly occurs at the set duty ratio α is generated.

  The number of rotation detection signals generated during one revolution of the engine can be appropriately set according to the load (in this embodiment, a tachometer) that supplies the rotation detection signal. For example, when the generator 1 is configured with 12 poles and the generator is driven via a pulley or the like by the engine, when the generator 1 rotates twice while the engine rotates once, the pulse signal generation circuit 203 generates 6 pulse signals during one revolution of the generator, and 12 pulse signals during one revolution of the engine. In this case, for example, if the tachometer is configured to display one rotation when receiving twelve pulses, a pulse signal is generated while the generator 1 makes one rotation with the proportionality constant k = 1. By configuring the rotation detection signal generating means so as to generate a pulse signal having the same frequency as the pulse signal output from the circuit 203 as the rotation detection signal, the engine speed can be displayed on the tachometer.

  The duty ratio α of the rotation detection signal is set to an appropriate value according to the request on the tachometer side. In the example shown in FIG. 5, the duty ratio α is set to 50%.

  In the above embodiment, the output voltage detection circuit 204 and the output voltage determination unit 205B are omitted so that the rotation detection signal generation means 205C generates the rotation detection signal even when the output voltage of the generator is equal to or lower than the reference value. If it is configured, as shown in the left half of FIG. 7 (A), a waveform having two peaks Vu1 and Vu2 and one valley formed between the peaks. When the generator 1 outputs the AC voltage Vu, the pulse signal generation circuit 203 performs the detection operation when the two peaks of the half wave of the output voltage Vu reach the detection values at times tx1 and tx2, respectively. Since the voltage Vin1 input to the input port IN1 of the microcomputer falls twice during the half wave period of the output voltage Vu, the microcomputer outputs as shown in the left half of FIG. Half-wave period of voltage It recognizes the two pulse signal at the time tx1 and tx2 to. Therefore, the rotational speed detected by the pulse signal recognized by the microcomputer becomes higher than the actual rotational speed, and the actual rotational speed is reflected as shown in the left half of FIG. The rotation detection signal Sr is generated at an interval smaller than the generation interval, and the engine rotation speed is detected to be higher than the actual rotation speed.

  As the rotational speed of the generator 1 increases, the output voltage Vu increases as shown in the right half of FIG. 7, and the voltage Vu is at a timing before the timing at which the peak portion Vu1 of the output voltage Vu is generated. Reaches the detection value and the valley does not fall below the detection value, the pulse signal is recognized only once in each half wave of the output voltage Vu, so that the rotation detection signal Sr is normal. To occur.

  On the other hand, when the rotation detection signal is generated only when the output voltage of the generator 1 exceeds the set reference value as in this embodiment, the reference value is set to an appropriate value. As shown in FIG. 6, the microcomputer causes the voltage signal Vin1 to fall only once in each half wave of the output voltage Vu as in the period after time ty in FIG. Since only the rotation detection signal Sr in which the engine speed is accurately reflected in the generation interval is generated, it is possible to prevent a situation in which the engine speed is erroneously detected. be able to.

  Normally, the generator output voltage is set to exceed the battery voltage at the normal rotation speed. Therefore, in order to minimize the range in which the rotation detection signal is not output, the reference value is the lower limit of the battery voltage setting range. Set it below the value. In addition, when the generator is configured such that a plurality of peaks and at least one valley appear in each half-wave waveform of the output voltage, the above reference value is set to the lower limit value of the battery voltage setting range. The output voltage detection circuit 204 is below when the trough appearing in the output voltage waveform does not fall below the detection value after the half-wave voltage of the generator output voltage Vu once exceeds the detection value. Is set to a value equal to or higher than the voltage value detected by.

  In the above example, the output voltage detection circuit 204 detects the average value of the three-phase AC voltage output from the generator 1, but the average value of the AC voltage of one of the three phases is determined. The output voltage detection circuit 204 may be configured to detect.

  In the above embodiment, the magnet type AC generator 1 is configured to output a three-phase AC voltage, but the number of phases of the magnet type AC generator is arbitrary.

  In the above embodiment, every time the pulse signal generation circuit generates a pulse signal, the average value of the time intervals between the latest n (n is an integer of 3 or more) pulse signals generated by the pulse signal generation circuit. The rotation detection signal generator 205 is configured to generate a rotation detection signal at a time interval proportional to the calculated average value, but the timing at which each pulse signal is generated without calculating the average value. The rotation detection signal generation unit 205 may be configured to generate the rotation detection signal at a time interval proportional to the time difference between the first pulse signal and the timing at which the previous pulse signal is generated.

  In the above embodiment, when the battery voltage becomes less than the lower limit value of the setting range, the trigger signal is simultaneously supplied to all the thyristors of the control rectifier circuit constituting the rectifier 201, and the battery voltage exceeds the upper limit value of the setting range. The battery charge control circuit 202 is configured to keep the battery voltage within a set range by stopping the supply of the trigger signal to all thyristors of the control rectifier circuit sometimes, but the conduction angle of the thyristor of the rectifier circuit is controlled. Thus, the battery charge control circuit 202 may be configured to keep the battery voltage within a set range.

DESCRIPTION OF SYMBOLS 1 Magnet type AC generator 2 Battery charger 201 Rectifier 202 Battery charge control circuit 203 Pulse signal generation circuit 204 Output voltage detection circuit 205 Rotation detection signal generation part 205A Pulse interval average value calculation means 205B Output voltage determination means 205C Rotation detection signal generation Means 206 Power supply circuit 207 Rotation detection signal output circuit 3 Battery 5 Tachometer

Claims (6)

A battery comprising: a rectifier that rectifies the output of a magnet type AC generator driven by an engine and supplies the rectifier to a battery; and a battery charge control circuit that controls the rectifier so as to keep the voltage across the battery within a set range. A charging device,
Every time it detects that the half-wave voltage to be detected reaches a set detection value as a half-wave to be detected as one of positive and negative half-waves of the AC voltage output by the generator A pulse signal generation circuit for generating a pulse signal;
An output voltage detection circuit for detecting an output voltage of the generator;
Output voltage determination means for determining whether or not the output voltage detected by the output voltage detection circuit exceeds a reference value;
The engine speed obtained from the pulse signal generated by the pulse signal generation circuit when the output voltage detection means determines that the output voltage detected by the output voltage detection circuit exceeds a reference value. Rotation detection signal generating means for generating a rotation detection signal including the information of
A battery charging device comprising:   The rotation detection signal generating means generates a time interval between the most recent n (n is an integer of 3 or more) pulse signals generated by the pulse signal generating circuit each time the pulse signal generating circuit generates a pulse signal. The battery charging device according to claim 1, wherein the rotation detection signal is generated at a time interval proportional to the calculated average value. The magnet type AC generator is configured to output a polyphase AC voltage,
The pulse signal generation circuit is configured to detect one half wave of positive and negative half waves of any one-phase AC voltage output from the generator as a detection target. Battery charger. The magnet type AC generator is configured to output a polyphase AC voltage,
4. The battery charger according to claim 1, wherein the output voltage detection circuit is configured to detect an average value of half waves of output voltages of all phases of the generator.   The battery charging device according to claim 1, 2, 3, or 4, wherein the reference value is set to be less than a lower limit value of a voltage setting range at both ends of the battery.   When the generator is configured such that a plurality of peaks and at least one valley appear in each half-wave waveform of the output voltage, the reference value is a setting range of the battery voltage. Output voltage when the trough appearing in the output voltage waveform does not fall below the detected value after the voltage of each half wave of the output voltage of the generator exceeds the detected value once. 5. The battery charging device according to claim 1, wherein the battery charging device is set to a value equal to or greater than a voltage value of an output voltage of the generator detected by the detection circuit.

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