JPH04322134A - Field controller for changing generator - Google Patents

Abstract

PURPOSE:To prevent battery voltage drop during low speed rotation by boosting the charges absorbed by a capacitor in a circuit for feeding a current to a field coil of a vehicle charging generator and then discharging to the field coil. CONSTITUTION:An alternator 4 is connected with a battery 1. A booster circuit is constituted of an inductor L1, diodes in FET1 and FET2 and a capacitor C1. A discharge circuit is constituted of the C1, diodes of the FET1 and FET2 and the L1. The CL is subjected to chopping at a frequency of several tens kHz with signals 1, 2 fed from an electronic circuit 11 thus boosting the terminal voltage of the C1. Upon turn ON of FET3 with a signal 3, the C1 is discharged through a diode D1 to a field coil 5. Generating current is absorbed by C1 upon increase of torque while CL is discharged upon decrease of torque to reduce the generating current thus controlling the torque of alternator. Consequently, battery voltage drop is prevented during low speed rotation.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a device for controlling the field coil current of a vehicle alternator, and is particularly directed to a device suitable for controlling the torque of an alternator and increasing the generated current during low-speed rotation. .

0002

[Prior art] As a prior art, Japanese Patent Application Laid-Open No. 61-58435
As seen in the issue, it was an effective method when the rotation was low and when the electrical load became large and the generated current decreased. However, there is no consideration for controlling the torque of the alternator, and there is no consideration for rapidly raising the field current by boosting the voltage.

0003

[Problems to be Solved by the Invention] An object of the present invention is to be able to control the torque of the alternator and increase the generated current during low-speed rotation, and to rapidly increase the field current to increase the load current. This prevents the battery voltage from decreasing accordingly.

0004

[Means for solving the problem] In order to keep the torque of the alternator unchanged, the energy generated by the alternator is stored in a capacitor through a booster circuit, regardless of the electrical load.
Torque is adjusted by reducing the generated energy by discharging the charge of the capacitor to the battery.

On the other hand, when the electric charge of the capacitor is applied to the field coil, the field coil current rises steeply. Therefore, a characteristic is obtained in which the battery voltage does not drop even if the electrical load increases during low-speed rotation.

[0006]

[Operation] Increasing the generated current of the alternator means increasing the torque, and decreasing the generated current means reducing the torque. Therefore, if the capacitor is charged at a voltage higher than the generated voltage, charging energy is required, and the generated current must be increased. By discharging the charge from the capacitor, the battery voltage can be kept constant even if the generated current decreases accordingly.

If the charging voltage of the capacitor is set higher than the battery voltage and the voltage is applied to the field coil,
A larger current can be passed through the field coil than when battery voltage is applied. In other words, even if during low-speed rotation, the battery voltage drops as the load current increases and adjustment becomes impossible with the regulator, the voltage applied to the field coil increases, so the field coil current can be increased, making adjustment possible. .

[0008]

[Examples] The present invention will be explained below with reference to Examples.

An electric load (not shown) such as a lamp or a wiper is connected to the (+) power line 2 and the (-) power line 3 of the battery 1.

The alternator 4 includes a field coil 5, a regulator 6, a stator coil 7, a full-wave rectifier diode 8, and a freewheel diode 1 connected in parallel with the field coil 5.
It is configured to supply from 0.

[0011] The regulator 6 controls the generated power to be constant.

The configuration of the booster circuit includes inductance L1,
It consists of field effect transistors FET1, diodes of FET1 and FET2, and capacitor C1.

The capacitor discharge circuit includes capacitors C1,
It consists of diodes of field effect transistors FET2 and FET1 and an inductance L1.

The difference between a booster circuit and a discharge circuit is determined by whether or not each field effect transistor is rendered conductive (chopper control). That is, signals 1 and 2 of the electronic circuit 11 determine whether the capacitor C1 is charged or discharged. The frequency of the chopper operation is several tens of KHz, and the greater the duty, the greater the amount of charging or discharging to the capacitor C1.

When the field effect transistor FET3 is turned on, the charge in the capacitor C1 flows to the field coil 5 via the diode D1. Then the field effect transistor F
When ET1 is operated as a chopper, it operates as a booster circuit, and the high voltage generated at this time is applied to the field coil 5 via the diode D1.

FIG. 2 shows these operations.

The time TO is the start of operation, and the capacitor C
1 voltage to a value V greater than the voltage of battery 1 (12V)
1 (for example, 18V).

Time T2 to T3 is when the torque of alternator 4 is increased, and the voltage of capacitor C1 is boosted to V1 (for example, 40V), and time T3 to T4 is when the torque of alternator 4 is increased.
Indicates when to reduce the torque of The capacitor voltage is V
Make sure it doesn't go below 1. During time T5 to T6, when the alternator 4 rotation speed is low, the load current is large, and the battery voltage is low, the field effect transistor
Operate ET1 and FET3.

The time T6 to T7 is a time for the voltage of the capacitor C1 to become V1.

[0020] Since increasing the torque during low-speed rotation tends to lower the battery voltage, the torque increase is not controlled.

From the following explanation, when the torque increases, the generated current is absorbed into the capacitor, and when the torque decreases, the electric charge in the capacitor is released to reduce the generated current and control the torque of the alternator.

If the operation of the regulator 6 can be controlled by a signal that can forcibly make it fully conductive, the effect of increasing or decreasing the torque can be ensured. This is shown in FIG.

[0023]

According to the present invention, it is possible to control the torque of the alternator without changing the battery voltage, and to prevent the battery voltage from decreasing during low speed rotation.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a field control device according to the present invention.

FIG. 2 is a characteristic diagram showing the operation of FIG. 1;

FIG. 3 is a detailed diagram of an electronic circuit according to the invention;

[Explanation of symbols]

1...Battery, 2...(+) power line, 3...(-) power line,
4... Alternator, 5... Field coil, 6... Regulator, 7... Stator coil, 8... Full wave rectifier diode, 9...
Freewheel diode, 10... Auxiliary diode, 1
1...Electronic circuit, 12...Signal circuit, 13...A/D circuit, 1
4...Microcomputer.

Claims (1)

[Claims] Claim 1: A vehicle charging generator (alternator), a battery, and a device (regulator) that detects the battery voltage and controls the field coil current of the alternator,
A switching element that has a booster circuit that has a capacitor that absorbs the generated current, and a discharge circuit that releases the electrical energy stored in the capacitor to the battery, and that can be applied from the output terminal of the capacitor to the field coil terminal of the alternator. A field control device for a charging generator, characterized by being provided with.