JP2767446B2 - Power supply control circuit for vehicle - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control circuit for a vehicle that is applied to, for example, melting ice of a windshield of an automobile, charging a battery, and supplying power to a general load. is there.

2. Description of the Related Art Conventionally, as an ice melting system such as a windshield of an automobile, there is one having a configuration as disclosed in Japanese Patent Publication No. 61-33735, for example.

Such a conventional ice melting system is, for example, as shown in FIG. 4, an alternator section (an AC generator with a built-in rectifier).
1 is connected to a regulator unit 3 via a changeover switch 2 and a resistance 4 of a conductive film forming a surface heating element of a windshield. Normally, the changeover switch 2 is switched to the regulator unit 3 side, and a solid line arrow is used. As shown, the regulator unit 3
The DC power of, for example, 12 V output adjusted by
For driving the general load 6 such as charging the lamp, lighting a lamp, and a wiper.

In a cold region or the like, when the frozen windshield is to be melted by ice, a high voltage is required. Therefore, the changeover switch 2 is switched to the surface heating element 4 side of the windshield, and the oil generator 1 and the general load are switched. 6, further, the regulator unit 3 is disconnected, and the electric power generated by the oil generator unit 1 is supplied only to the surface heating element 4 to generate heat, as indicated by the dotted arrow, so that the windshield is melted. That is the current situation.

[Problems to be Solved by the Invention] However, in the conventional circuit configuration described above,
Since the alternator unit 1 and the battery 5 are separated during the melting of the ice, the general load 6 during the melting of the ice includes the battery 5.
The DC power of 12 V is supplied only from the power supply, and if the vehicle runs for a long time with the general load 6 being used as it is, the problem that the battery 5 is overdischarged easily occurs.

[Object of the Invention] The present invention has been made in view of the above circumstances, and has as its object to supply normal power to a battery and a general load, and to generate surface heat of a window glass required for melting ice. It is an object of the present invention to provide a vehicle power supply control circuit capable of simultaneously supplying a high-voltage power to a body.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides an alternator unit including a rotor coil and a Y-connected stator coil and connecting a diode constituting a rectifying bridge circuit to the stator coil. A regulator section for detecting the output voltage and battery voltage of the alternator section and controlling the exciting current flowing through the rotor coil to adjust the output; and a neutral point of the stator coil of the alternator section and connected to each lead-out end. A switching circuit for extracting an AC output from a phase having a middle potential among the three-phase AC outputs, and a step-up transformer for boosting the output of the switching circuit and supplying the boosted output to a load. It is.

In this case, the alternator unit uses only two phases of the three-phase AC output, that is, the phase at the highest potential and the phase at the lowest potential, and uses the AC output for battery charging, control, magnetic field, and the like. Preferably, an AC / DC converter is connected to the output side of the step-up transformer for boosting the output of the switching circuit.

[Operation] That is, according to the present invention, a switching circuit is connected to the neutral point and each lead end of the Y-connected stator coil of the alternator section, and the AC output from the phase having the middle potential in the three-phase AC output is started. The output of this switching circuit is stepped up by a step-up transformer and supplied to a load, while the exciting current flowing through the rotor coil of the alternator section is controlled by a regulator section to adjust the output to a battery and a general load. Therefore, normal power to the battery and the general load and high-voltage power to the load required for ice melting can be generated at the same time.

[Embodiment] Hereinafter, the present invention will be described in detail with reference to an embodiment shown in FIG. 1 to FIG.

FIG. 1 shows the overall configuration of a vehicle power supply control circuit according to the present invention applied to, for example, an ice melting system for a windshield of an automobile. In the figure, reference numeral 11 denotes an alternator. The alternator 11 includes a rotor coil Gr, and the stator coil Gs of the Y-connection, the diode D ₁ to D ₆ constituting the connected rectifier bridge circuit to the stator coil Gs, half of the circuit of the rectifier bridge circuit and a diode D ₇ to D ₉ constituting the corresponding arm, the common connection point of the diodes D ₇ to D ₉ constituting the arm (cathode side), one end of the rotor coil Gr, the regulator unit 12 to be described later , And the other end of the rotor coil Gr is connected to a connection terminal F of the regulator unit 12, and the (+) of the rectifier bridge circuit is connected to the charge detection terminal L of the rectifier bridge circuit.
Side output terminal, i.e. the cathode side of the diode D ₁ to D ₃ in the main electrical output terminal B of the regulator unit 12, also of the rectifier bridge circuit (-) side output terminal, i.e. of the diode D ₄ to D ₆ The anode side is connected to a common ground terminal E.

The regulator unit 12 includes an alternator unit 11
In order to adjust the output voltage of the AC generator, the exciting current flowing through the rotor coil Gr is controlled. The collectors of the Darlington-connected transistors Tr ₁ and Tr ₁ ′ are connected to the connection terminal F, and the emitter is connected to the ground terminal. E to form a series circuit with the rotor coil Gr. A flywheel diode is connected to the connection terminal F.
D ₁₀ of which is connected in parallel with the rotor coil Gr. Further, the base of the transistor Tr ₁ ′ has a resistance R
₁ of one end, is connected to the collector of the transistor Tr _2,
The other end of the resistor R _1, together with formed by connecting the common connection point of the diodes D ₇ to D ₉ of the alternator section 11, the resistor R ₂
It is connected to the base of the transistor Tr ₃ through.

Also, the between the main terminals B and collector of the transistor Tr ₃ of the regulator unit 12, and a series circuit of resistors R _3, R ₄ is not connected, the emitter of the transistor Tr ₃ is
Together they are connected to the base of the transistor Tr ₂ via a zener diode ZD, connected to the earth terminal E through the resistor R _5. Wherein between the resistors R _3, R ₄ of the connection point and the terminal S, the diode D ₁₁ is connected to the terminal S
Is connected to the (+) end of the battery 13 together with the main terminal B, while the charge detection terminal L of the regulator 12 is
The battery 13 is connected to the (+) end of the battery 13 via a series circuit of an ignition switch 14, a charge lamp 15, and a diode 16, and the (-) end of the battery 13 is connected to the ground terminal E. .

Further, reference numeral 20 in the figure denotes a power supply control unit in an ice melting system for a windshield of an automobile, for example. This power control unit 20
Is the switching circuit 21, step-up transformer 22, AC / DC converter 2
3, windshield auto fogger controller 2
4, windshield freeze prevention switch 25 and temperature sensor 2
6, the switching circuit 21 has an input terminal connected to a neutral point and each lead-out terminal of the Y-connected stator coil Gs of the alternator section 11, and has an output terminal connected to the primary of the step-up transformer 22. As shown by the dotted line in FIG. 2 (a), the AC output is controlled so as to take out the AC output from the phase at the middle potential of the three-phase AC output as shown by the dotted line in FIG. Further, the step-up transformer 22 boosts the output of the switching circuit 21 and supplies a desired power to the resistance 27 of the conductive film forming the surface heating element of the windshield by the energizing operation of the windshield freezing prevention switch 25. It has become.

Next, the operation of the power supply control circuit having the above configuration will be described.

First, closing the ignition switch 14, is supplied base current to the transistor Tr _3, the transistor Tr ₃
There together turns ON, the transistor Tr ₁ is also turned ON, thereby, the excitation current flows through the rotor coil Gr, output to the alternator section 11 is caused, it is supplied to the battery 13 and the common load (not shown). At this time, if the voltage of the charge detection terminal L is lower than the battery voltage, the charge lamp 15 maintains the lighting state, indicating that the battery 13 is being charged, and the voltage of the charge detection terminal L is lower than the battery voltage. When the voltage rises, the charge lamp 15 is turned off to notify the end of charging of the battery 13, and at the same time, the output of the alternator unit 11 is used as a control and field power supply.

The charging of the battery 13 progresses, becomes a certain value or more in the voltage of the main terminal B, and becomes high emitter potential of the transistor Tr _3, becomes the Zener diode ZD is conductive,
The transistor Tr ₂ is turned ON, the transistor Tr ₁ is the result made OFF, the output of the alternator section 11 is depleted, whereby, over-discharge of the battery 13 is prevented.

On the other hand, when the switching circuit 21 is operated while the output of the alternator unit 11 is being supplied to the battery 13 and the general load, the middle potential of the three-phase AC output indicated by the dotted line in FIG. The AC output is extracted from the phase, and the output of the alternator unit 11 at this time is as shown in FIG. 2 (b), whereby the phase at the highest potential in the three-phase AC output is The AC output of only the two phases having the lowest potential is used for charging the battery 13, controlling the battery, controlling the field, and the like.

Further, the output of the switching circuit 21 is applied to the primary winding of the step-up transformer 22 to be boosted, and the AC
The current obtained by the AC / DC conversion by the / DC converter 23 is supplied to the load 27 forming the surface heating element of the windshield FG through the controller 24 or the windshield freezing switch 25, and the load 27 forming the surface heating element The fever function prevents fogging and freezing of the windshield FG and melts the ice.

By the way, assuming that the DC output voltage (voltage between terminals BE) of the alternator section 11 is E, the forward voltage per diode is ΔE, and the effective value of the phase voltage is V, Is given by the following equation: E = 2.34V−2 · ΔE By substituting E = 14.5 (v) and ΔE = 0.6 (v) into this equation, V = 6.7 (v) is obtained.

Therefore, assuming that the effective value of the voltage at the dotted line in FIG. Becomes

Further, since the load 27 of the windshield FG is determined by the coating thickness of the heating element, for example, the windshield FG
In order to clear the visible light transmittance of 70%, the minimum value of the resistance value R is 2.7 (Ω). As shown in FIG. 3, assuming that the step-up transformer 22 is an ideal transformer, _{E 2 = (N 2 / N} 1) · E 1 I 2 = E 2 / RI 1 = (R / E 1) · I 2 2 becomes, R = 2.7 (Ω), E 1 = V '= 2.8 (v ) it is because, when the I ₁ and the maximum output of the alternator section _{11 (60A), I 2 =} 7.9 (a) E 2 = 21.3 (v) N 2 / N 1 = 7.6 is obtained.

As a result, power to the load 27 forming a surface heating element of the windshield FG required for deicing ^{_{is, I 2 2 · R = 160}} (W) are obtained, for example, the power density of application of the current car, 160 (W) /0.6 (m ² ) = 280 (W / m ² ), and the performance of hot-wire printing on the rear glass of the current car is about 260 (W / m ² ), so there is no problem in terms of performance. There was no.

[Effects of the Invention] As is apparent from the above description, the present invention connects the switching circuit to the neutral point and each lead end of the Y-connected stator coil of the alternator section, and outputs the switching circuit in the three-phase AC output. AC output is extracted from the phase that is the potential of the power supply, the output is boosted by a transformer, AC / DC converted as necessary, and then supplied to a load such as a windshield. Normal power to the ice melt and high voltage power to the load required for the ice melting can be generated simultaneously, thereby prolonging the use for a long period of time, for example, when traveling in the state of melting ice. This also provides an excellent effect that the overdischarge of the battery as in the related art can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a vehicle power supply control circuit according to the present invention, and FIGS. 2 (a) and 2 (b) are explanatory diagrams showing a three-phase AC waveform and an output waveform of an alternator section. 3 is an explanatory diagram of the voltage conversion process, and FIG. 4 is an explanatory diagram showing an example of a conventional vehicle power supply control circuit. 11 ... Alternator, Gr ... Rotor coil, Gs ... Stator coil, 12 ... Regulator, 13 ... Battery, 14 ... Ignition switch, 15 ... Charge lamp, 16 ... Diode, 20 ... Power supply Control unit, 21: Switching circuit, 22: Step-up transformer, 23: AC / DC converter, 24: Controller, 25: Windshield freezing prevention switch, 26: Temperature sensor, 27: Load, FG ... windshield.

Claims (3)

(57) [Claims] An alternator comprising a rotor coil and a Y-connected stator coil, and a diode constituting a rectifying bridge circuit connected to the stator coil, an output voltage and a battery voltage of the alternator being detected and the rotor coil being detected. A regulator section for controlling output by controlling an exciting current passed to the generator, and a phase change from a phase at a middle potential in a three-phase alternating current output connected to a neutral point of the stator coil of the alternator section and each lead end. A power supply control circuit for a vehicle, comprising: a switching circuit for extracting an output; 2. The alternator section uses only two phases of a three-phase AC output, a phase at the highest potential and a phase at the lowest potential, for charging, controlling and field-charging the battery. The power supply control circuit for a vehicle according to claim 1, wherein the power supply control circuit is used. 3. The vehicle power supply control circuit according to claim 1, wherein an AC / DC converter is connected to an output side of the step-up transformer for boosting the output of the switching circuit.