JP2586516B2 - Voltage regulator for vehicle charging generator - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage regulator for a vehicle charging generator, and more particularly to a voltage regulator capable of obtaining high output with a small-sized charging generator.

[Related Art] With the recent development of electronics of vehicles, it has been desired to increase the output of a charging generator that supplies operating power to electrical components mounted on the vehicle. In such a high output, an increase in the supply current does not drastically increase the loss due to the internal resistance of the charging generator, causing problems such as a decrease in output efficiency and heat generation in the charging generator.

Therefore, for example, Japanese Patent Application Laid-Open No. 58-95999 proposes a configuration in which two sets of stator coils of a charging generator are provided and these are connected in parallel at high output to reduce the internal resistance.

[Problems to be Solved by the Invention] However, the above proposed structure has a problem that the structure of the charging generator is complicated, which leads to an increase in cost and a certain increase in size.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a voltage regulator that can easily and inexpensively increase the output of a charging generator without changing the structure of a conventional charging generator. And

[Means for Solving the Problems] The configuration of the present invention will be described with reference to FIG. 1. The power generation of the charging generator 2 rotated by the vehicle engine and connected to the vehicle-mounted battery 3 and the electric load 4 via the charging line 6 The voltage regulator 1 for controlling the charging voltage of the vehicle-mounted battery 3 at a constant regulated voltage by connecting the reactors 11A and 11B and the reactors 11A and 11B in the charging line 6 during the closing operation. When opening, the reactor
Switching means 12A and 12B for connecting both ends of 11A and 11B to the on-vehicle battery 3 to form a closed circuit, rotation speed detection means 5 for detecting the rotation speed of the charging generator, and each rotation speed of the charging generator 2 The generator output voltage at which the output power is
A switching control means 13 for activating the switching means 12A and 12B with E1 as the adjustment voltage and E2 as the adjustment voltage and E2 / E1 as the ON duty.

[Operation] In the voltage regulator of the present invention, the switching means is operated with the ON duty, whereby the generator output voltage is always maintained at the voltage E1 at which the output power becomes the maximum, and the charging generator is operated at the maximum capacity. Activated. Therefore, it is possible to efficiently supply the maximum current to the electric load.

The voltage E1 rises with an increase in the number of revolutions of the charging generator, and becomes much higher than the adjustment voltage E2 in a high rotation range. Therefore, the stator coil current of the charging generator at the maximum output is suppressed to be small, and The internal resistance loss is reduced.

[Effect] As described above, according to the present invention, the maximum output of the charging generator can be obtained, and the resistance loss in the charging generator in this state can be reduced. It is possible to supply a large current to the electric load.

In the present invention, since the conventional charging / generator structure can be used as it is, high output can be realized simply and inexpensively.

[Embodiment] In FIG. 1, a voltage regulator 1 has a transistor 15 for controlling excitation of a rotor coil 21 of a charging generator 2 connected to an engine and rotating, the transistor 15 being an output signal of a control circuit 13. Activated by That is,
The charging voltage is fed back from the vehicle-mounted battery 3 to the control circuit 13, and the rotor coil 2 is controlled to maintain the charging voltage at a constant regulated voltage (for example, 13.5V) E2.
1 Excitation is duty controlled.

The charging generator 2 has a stator coil 22 for generating a generated voltage and a full-wave rectifier 23 for rectifying the generated voltage. The rectified generator output is connected in parallel to the vehicle-mounted battery 3 and the charging battery 6 via a charging line 6. The electric load 4 is supplied.

The charging line 6 is branched into two on the way, and the switching transistors 12A, 12B
Also, reactors 11A and 11B are provided in series with this.
The anode is located on the ground side between the connection point of both and ground, and the freewheeling diode is
14A and 14B are provided.

The transistors 12A and 12B are switched by the control circuit 13 as described later, and are alternately operated to increase the switching frequency as a whole. The control circuit 13 is connected to a rotation speed detector 5 for detecting the rotation speed of the charging generator 2.
A smoothing capacitor 16 is provided at the output section of the first embodiment.

FIG. 2 shows an equivalent circuit of the voltage adjusting device having the above configuration. In the figure, E0 is the voltage generated by the generator, and R0 is its internal resistance. E1 is the output voltage of the switching transistor 12, E2 is the battery charging voltage equal to the adjustment voltage,
E3 is the voltage drop due to the internal resistance R0, I1 is the generator output current, and I2 is the diode 14 when the transistor 12 is turned off.
, And I3 is a current supplied to the electric load 4.

By the way, the output power P of the charging generator having the internal resistance R0 is expressed by the following equation, and the output voltage E1 that maximizes the power P
Is E0 / 2.

P = (E0−I1 × R0) × I1 Here, it is known that the power generation voltage E0 of the charging generator increases in proportion to the rotation speed as shown in FIG. (= E0 / 2) also increases as the rotational speed increases, and exceeds the adjustment voltage E2 at the rotational speed N1 or higher.

Thus, the voltage E1 is not equal to the voltage E2 below the rotation speed N1, and the switching transistor 11 is operated so that the average value is always E0 / 2 above the rotation speed N1. As a result, the maximum output is always obtained at the rotation speed N1 or more, and the voltage E1 at this time is higher than the voltage E2, so that the current I1 in the charging generator becomes smaller than that of the conventional one.

In order to realize this, the control device 13 has a rotation speed N1.
The value of E0 at each rotation speed described above is stored in advance,
When the rotation speed is N1 or less, the transistor 12 is always in the ON state. When the iron opening number is N1 or more, the transistor 12 is operated with an ON duty of α = E2 / E1 = 2 · E2 / E0.

The changes over time in the voltage E1, the currents I1, and I3 at this time are shown in FIGS. In the figure, T0 is a repetition period, and the shorter this is, the better the voltage control is, but it is, for example, about 20 KHz in consideration of the operation performance of the transistor. T1 indicates the time when the transistor 12 is ON, and T2 indicates the time when the transistor 12 is OFF.

As shown in FIG. 5 (3), when the transistor 12 is OFF, the electric load 4 is generated by the electromotive force generated in the reactor 11.
Is supplied with a current I2.

FIG. 6 shows the effect of the present invention performing the above operation. The broken line in the figure is the output current of the charging generator by the conventional voltage regulator (this is also the internal current). In comparison with this, in the voltage regulator of the present invention, the current I3 is proportional to the rotation speed. The average value increases linearly, so much more current can be supplied to the electric load than before, and the current I1 inside the generator is smaller than before, causing internal losses. And efficient power supply is possible.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a voltage regulator, FIG. 2 is an equivalent circuit diagram thereof, FIGS. 3 and 4 are diagrams showing a change characteristic of each part voltage with respect to a generator rotation speed, and FIG. FIG. 6 is a graph showing the change, and FIG. 6 is a graph showing the output characteristics of the current with respect to the number of revolutions of the generator showing the effect of the present invention. 1. Voltage regulator 11, 11A, 11B Reactor 12, 12A, 12B Switching transistor (switching means) 13 Control circuit (control means) 14, 14A, 14B Flywheel diode 2. Charge Generator 3 On-board battery 4 Electric load 5 Rotation detector (rotation detection means) 6 Charge line

Claims (1)

(57) [Claims] 1. A voltage regulator for controlling the power generation of a charging generator which is rotated by a vehicle engine and connected to a vehicle-mounted battery and an electric load via a charging line to maintain the charging voltage of the vehicle-mounted battery at a constant regulated voltage. A charging device including a reactor, switching means for interposing the reactor in the charging line during a closing operation, and connecting both ends of the reactor to the vehicle-mounted battery during an opening operation to form a closed circuit; Rotation speed detecting means for detecting the rotation speed of the generator, and the generator output voltage at which the output power is maximum at each rotation speed of the charging generator is E1, the adjustment voltage is E2, and the switching is performed with the ON duty of E2 / E1. And a switching control means for operating the means.