JP3618081B2 - Rectifying device for charging generator for vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rectifier for a vehicle charging generator, and more particularly to a rectifier for a vehicle charging generator having a three-phase full-wave rectifier using a power MOS transistor.
[0002]
[Prior art]
Conventionally, as a rectifier using a power MOS transistor, there is a rectifier for a charging generator described in Japanese Patent Application Laid-Open No. 8-336238.
[0003]
The rectifier described in this publication is a vehicle power supply that can efficiently extract the output of an AC rotating electrical machine while ensuring low rectification loss even in a low-speed rotation region without employing an extra surge absorbing circuit. The purpose is to provide a system.
[0004]
In the rectifier described in this publication, the phase of the generated voltage is detected and the gate of each power MOS transistor is turned on and off.
[0005]
[Problems to be solved by the invention]
However, in the case of the rectifier described in the above publication, the ON / OFF operation of the power MOS transistor is controlled by detecting the power generation voltage of each phase. When ON, the ON resistance of the power MOS transistor is 3 mΩ, and when the current flowing into the U-phase is 10A, only 0.03V and 50A change only 0.15V (the current is 10A and 30A) The difference voltage is only a slight change of 0.15V−0.03V = 0.12V).
[0006]
As a result, when only the phase voltage of the generated voltage is detected to control the ON / OFF operation of the power MOS transistor, the power MOS transistor is turned off with a certain amount of current flowing. Will occur.
[0007]
In this case, in the worst case, a surge voltage exceeding the withstand voltage of the power MOS transistor is generated, which may damage the power MOS transistor.
[0008]
Further, depending on the time when the power MOS transistor is turned from ON to OFF, the power MOS transistor element abnormally generates heat or the switching surge that occurs causes the radio noise characteristics to be significantly deteriorated.
[0009]
An object of the present invention is to realize a rectifier for a vehicle charging generator in which heat generation is suppressed and noise generated is reduced while the power MOS transistor is turned on and off while being simple and inexpensive. .
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is configured as follows.
(1) A field winding that rotates due to the rotation of the engine and generates a rotating magnetic field, an armature winding that receives the field winding and generates a current, and a multiphase AC output generated in the armature winding A multi-phase full-wave rectifier, and the multi-phase full-wave rectifier is composed of a series circuit of a high-potential side MOS power transistor and a low-potential side MOS power transistor for each phase. but in-vehicle charging generator which is connected to the corresponding terminals and the ground side of the phase of the positive electrode side and the armature winding of the battery, the phase current flowing in the terminals of at least one phase of the armature winding The current detection means for detection and the polarity of the phase current of one phase detected by the current detection means are judged, and when the polarity is inverted, the output state is inverted between “1” and “0”. One phase reference signal and one phase reference A reference signal of another phase whose output state is inverted to “1” and “0” is generated after a lapse of a predetermined time from the time when the quasi signal is inverted, and the reference signal of one phase and the other phase are generated. Control means for controlling the on / off operation of the MOS power transistor provided for each phase based on the reference signal .
[0011]
(2) Preferably, in the above (1), the high potential side MOS power transistor and the low potential side MOS power transistor have two delays different from each other from the reference signal of one phase and the reference signal of the other phase. The high-potential side MOS power transistor and the low-potential side MOS power transistor are controlled in operation so as to be turned on with a delay of time .
[0012]
(3) Preferably, in the above (1) and (2), when the number of phases of the multiphase AC output is n and k is a natural number up to 2 (n-1) / n, the one phase The reference signal of the other phase is generated with the predetermined elapsed time as a time obtained by multiplying the time from when the reference signal is inverted to the next polarity inversion by 2 k / n.
[0013]
(4) Preferably, in the above ( 3 ), the multiphase AC output is a three-phase AC output .
[0014]
(5) Preferably, in the above (1), each of the MOS power transistors is a trench type.
[0015]
The one-phase (U-phase) current of the armature winding is detected by a shunt resistor, the polarity of the current flowing through the U-phase terminal is judged, and the time from when the polarity is inverted to the next polarity inversion is maintained. The V-phase MOS power transistor is driven when the division ratio time elapses from the holding time. Further, the W-phase MOS power transistor is driven when the division ratio time × 2 has elapsed from the holding time. Thus, by sequentially driving the power transistor, the MOS power transistor is driven when the current of each phase of U, V, and W is the lowest value by detecting the current of only one phase, and at the time of ON / OFF operation It is possible to minimize heat generation and reduce noise.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EMBODIMENTS Hereinafter, a control device for a vehicle charging generator according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
1 to 6 are control circuit diagrams showing a charging system of an automotive charging generator according to an embodiment of the present invention.
[0017]
1 to 6, the field winding 13 is attached to a rotor (not shown), and rotates in synchronization with the rotation of the engine to generate a rotating magnetic field.
[0018]
A flywheel diode 19 connected in parallel to the field winding 13 is connected to absorb switching noise.
[0019]
The armature winding 11 wound around a stationary iron core (not shown) facing the rotor with a gap has an AC waveform according to the magnitude of the rotating magnetic field generated by the field winding 13. Output the voltage.
[0020]
The AC output from the armature winding 11 is full-wave rectified by rectifying power MOS transistors 121, 122, 125, 126, 128, and 129 that constitute the three-phase full-wave rectifier 12.
[0021]
Here, the power MOS transistors 121, 122, 125, 126, 128, and 129 are configured by P-channel power MOS transistors on the high potential side and N-channel power MOS transistors on the low potential side. A drive system using a boosted voltage in which a channel type is used and a gate voltage drive is configured by a charge pump circuit may be used.
[0022]
Here, the resistors 124, 127 and 123 are pull-up resistors for the P-channel type power MOS transistors 128, 125 and 121.
[0023]
Next, the gate signals of the rectifying power MOS transistors 121, 122, 125, 126, 128, and 129 are controlled by the control circuit 21. The control circuit 21 has gate drive circuits 211, 212, and 213 for controlling the power MOS transistors 121, 122, 125, 126, 128, and 129 on the high potential side and the low potential side of each phase.
[0024]
The gate drive circuit 211 is a W-phase gate drive circuit. As shown in FIG. 2, the gate drive circuit 211 includes resistors 2112, 2114, 2115, 2117, and 2118, transistors 2111, 2113, and 2119, and an operation switch. 2116 and a delay time generation circuit 2110.
[0025]
The resistor 2112 is connected to the base of the transistor 2111, and the resistor 2114 is connected to the base of the transistor 2113. The switch 2116 is connected to the collector of the transistor 2113 through the resistor 2115. The resistor 2118 is connected to the collector of the transistor 2119, and the resistors 2114 and 2112 are both connected to the delay time generation circuit 2110. The delay time control circuit 2110 is also connected to the collector of the transistor 2119.
[0026]
Similarly, the V-phase gate driving circuit 212 includes resistors 2122, 2124, 2125, 2127, and 2128, transistors 2121, 2123, and 2129, an operation switch 2126, and a delay time generating circuit 2120, as shown in FIG. .
[0027]
The U-phase gate drive circuit 213 includes resistors 2132, 2134, 2135, 2137, and 2138, transistors 2131, 2133, and 2139, an operation switch 2136, and a delay time generation circuit 2130, as shown in FIG.
[0028]
In order to switch the current of each phase with high accuracy, a current detecting shunt resistor 1201 is provided in the U phase of the rectifier 12, and the current flowing through the shunt resistor 1201 is detected, and a power MOS arranged in each phase. In order to control each operation timing of the transistor, the control circuit 21 has a current detection circuit 215.
[0029]
As shown in FIG. 5, the current detection circuit 215 includes resistors 2152, 2153, 2154, 2156, and an OP amplifier 2151 as current detection units, and determines the polarity from the current detected by the current detection unit, A gate signal generation circuit 2150 that generates a time-distributed signal is provided.
[0030]
Further, the control circuit 21 has a voltage control circuit 214 for controlling the current flowing through the field winding 13 and controlling the generator output voltage to a constant voltage.
[0031]
FIG. 6 is a circuit configuration diagram of the voltage control circuit 214. The voltage control circuit 214 controls the power switch unit 20 that performs voltage control.
[0032]
A power MOS transistor 202 and a resistor 203 which are power switches of the power switch unit 20 are for controlling the field winding 13, and the power MOS transistor 202 is a resistor 58, 59, 57 of the voltage control circuit 214 shown in FIG. The output voltage is controlled to one voltage by a voltage detection circuit constituted by a reference power supply 60 and a comparator 61.
[0033]
The output controlled by the voltage control circuit 214 is supplied to the battery 14 via the output terminal “B”, and the battery 14 is charged. At the same time, the output of the three-phase full-wave rectifier 12 is supplied from the output terminal “B” to the electric load 17 such as a lamp via the load switch 18.
[0034]
The charging indicator lamp 16 includes resistors 161 and 163, a light emitting diode 162, and a diode 164. The charging indicator lamp 16 is connected to the key switch 15, and closing the key switch 15 closes the power switch unit 20 and the pMOS transistor 201. The lamp 16 is turned on.
[0035]
The power supply start / stop circuit is a circuit for starting the power supply when the key switch 15 is closed and generating a power supply voltage VCC for supplying a current to each circuit. When the key switch 15 is opened, This is a circuit for stopping.
[0036]
As a power supply start / stop circuit, resistors 77 and 81, diodes 78, 79 and 80, and a comparator 76 shown in FIG. 6 are connected to the L terminal connected to the charge indicator lamp 16 and the drain of the MOS transistor 201. , A reference voltage 75, and a NOR circuit 82.
[0037]
Note that, as the start-up of the power source, while the generator is generating power, the one-phase voltage of the armature winding 11 is detected by the PV terminal so that the power source does not go down even if the charging indicator lamp 16 is disconnected. In the circuit composed of resistors 62, 63, 68, diodes 64, 66, a capacitor 65, and a transistor 67, the power is held while a one-phase voltage is generated.
[0038]
In order to turn on / off the charging indicator lamp when the PV terminal voltage is equal to or lower than a certain set voltage, a circuit is constituted by transistors 69 and 72 resistors 70 and 71 as shown in FIG. .
[0039]
With the above configuration, details of the operation of the rectifier will be described with reference to FIGS.
When the key switch 15 is closed, the L terminal voltage becomes substantially equal to the voltage of the battery 14, the diodes 78, 79, 80 of the voltage control circuit 214 are turned on and the input of the NOR circuit 82 becomes "1". Since the output of the NOR circuit 82 is “0” regardless of the other input signal, the transistor 52 becomes conductive.
[0040]
The power supply voltage VCC is generated by the conduction of the transistor 52, the gate voltage is applied from the VCC to the MOS transistor 201 via the resistor 73 (FIG. 6), and the MOS transistor 201 of the power switch unit 20 starts to conduct.
[0041]
Here, since the reference voltage 75 is set so that the drain voltage when the MOS transistor 201 is ON is higher than the reference voltage 75, the output of the comparator 76 is “1”, and the NOR circuit 82. "0" is output as the output. Note that the charge indicator lamp 16 is lit by the conduction of the MOS transistor 201.
[0042]
Here, since the voltage obtained by dividing the voltage of the B terminal by the resistors 58 and 59 (FIG. 6) is lower than the reference voltage 60, the output of the comparator 61 becomes “0”. As a result, the MOS transistor 202 An excitation current is supplied to the field winding 13 in the ON state.
[0043]
Next, when the engine is started and the rotational speed of the generator gradually increases, the armature winding 11 outputs a voltage having an AC waveform according to the magnitude of the rotating magnetic field generated by the field winding 13. To do.
[0044]
This generated voltage is input from the PV terminal, divided by resistors 62 and 63, the divided voltage is half-wave rectified by diode 64, only the positive component is taken out, and smoothed by capacitor 65.
[0045]
The smoothed voltage is amplified by the transistor 69. By operating the transistor 72 via the resistor 70, the MOS transistor 201 is turned off and the charging warning lamp 16 is turned off.
[0046]
Further, the voltage smoothed by the capacitor 65 is operated by turning on the transistor 67 via the resistor 68 and the diode 66, so that the output terminal voltage of the NOR circuit 82 becomes "0".
[0047]
As a result, even when the charge indicator lamp 16 is turned off or the key switch 15 is accidentally turned off, the power supply voltage VCC is stably supplied, so that each control circuit operates normally and the generator generates power. To continue.
[0048]
Here, when the engine speed further increases and the output current of the generator is supplied to the battery 14 via the B terminal, the voltage applied to the battery 14 increases. This increased voltage is detected via the B terminal, and the divided voltage of the resistors 58 and 59 and the reference voltage 60 are compared by the comparator 61.
[0049]
As a result of comparing the divided voltage of the resistors 58 and 59 with the reference voltage 60, when the divided voltage is higher than the reference voltage 60, the output of the comparator 61 becomes “1”, and as a result, the MOS transistor 202 is turned off, The current flowing through the field winding 13 is interrupted, and the generator stops generating power.
[0050]
As described above, the voltage of the battery 14 is detected by the B terminal and the current flowing in the field winding 13 is controlled. As a result, the adjustment voltage is controlled to be constant.
[0051]
The above is the operation for controlling the current flowing in the field winding 13 and keeping the output voltage constant.
[0052]
Next, the operation of the rectifier will be described.
First, when the engine is started and the rotational speed of the generator is gradually increased, a voltage having an AC waveform is output to the armature winding 11 according to the magnitude of the rotating magnetic field generated by the field winding 13. To do.
[0053]
Here, an alternating current starts to flow through the U-phase current detection shunt resistor 1201, and the generated current is amplified by an amplifier circuit composed of an OP amplifier 2151, a resistor 2152, and resistors 2153, 2154, 2156 of the current detection circuit 215. Are input to the gate signal generation circuit 2150.
[0054]
Then, the gate signal generation circuit 2150 to which the amplified current of the shunt resistor 1201 is input detects the direction in which the phase current flows and the switching timing thereof, and the basic VG1 on the time axis t0 as shown in FIG. Generate an output signal.
[0055]
Here, the high-potential-side power MOS transistor and the low-potential-side power MOS transistor originally perform operations opposite to each other. When the high-potential side is ON, the low-potential side is OFF.
[0056]
In one embodiment of the present invention, a P-channel power MOS transistor is used on the high potential side and an N-channel power MOS transistor is used on the low potential side, so that the ON / OFF timing of the gate voltage applied to both transistors is used. The operation is basically the same.
[0057]
However, when the high-potential side P-channel power MOS transistor and the low-potential side N-channel power MOS transistor are turned on at the same time, in order to prevent short-circuit current from flowing into the battery 14, As shown, a delay time t1 is provided.
[0058]
Further, in a state where the key switch 15 is OFF and the engine is stopped as a vehicle, it is desirable from the viewpoint of current consumption that both the high-potential side and low-potential side power MOS transistors are OFF. In FIG. 2, the gate drive circuits 211, 212, and 213 shown in FIGS. 2, 3, and 4 are provided with switches SW1, SW2, and SW3 that are turned off when the engine is stopped.
[0059]
First, the basic VG1 output signal is generated and at the same time the SW1 signal is turned ON.
[0060]
Next, the time TA is measured, and with this time TA as a reference, the VG2 output signal is output after the time TA × 2/3 hours, and the VG3 output signal is output after the time TA × 4/3 hours.
[0061]
The high potential side operation start switches SW2 and SW3 are turned on simultaneously with the output of the VG2 output signal.
[0062]
In the case of three-phase full-wave rectification, the phase difference between the U phase, the V phase, and the W phase is 120 °. The operation is delayed by 4/3.
[0063]
The gate signal generation circuit 2150 of the current detection circuit 215 continuously detects and measures a change in the current flowing in the U phase, measures the reference time TB after the reference time TA, and then the reference time TC. Then, the change in the rotational speed of the generator is sequentially taken in and a VG1 output signal is generated, and a signal shifted by 2/3 and 4/3 hours of the measured time is generated as an output signal of VG2 and VG3.
[0064]
Next, the generated VG1 signal is input to the U-phase gate drive circuit 213, and the delay time generation circuit 2130 outputs a signal with a delay between the MN1 output signal and the MP1 output signal. Then, the power MOS transistor 122 on the low potential side is operated, and the power MOS transistor 121 on the high potential side is operated with the MP1 output signal.
[0065]
Here, the MN1 output signal has a delay time t1 when it changes from 0 (Low) to 1 (High), and the MP1 output signal has a delay time when it changes from 1 (High) to 0 (Low). t2. As a result, the power MOS transistors on the high potential side and the low potential side are prevented from being turned on simultaneously.
[0066]
Similarly, for the V phase, the VG2 output signal is input to the V phase gate drive circuit 212, and the delay time generation circuit 2120 outputs a signal with a delay between the MN2 output signal and the MP2 output signal. The power MOS transistor 126 on the potential side and the power MOS transistor 125 on the high potential side are operated.
[0067]
Similarly, for the W phase, the VG3 output signal is input to the W-phase gate drive circuit 211, and the delay time generation circuit 2110 outputs a signal with a delay between the MN3 output signal and the MP3 output signal. The power MOS transistor 129 on the potential side and the power MOS transistor 128 on the high potential side are operated.
[0068]
Further, when the engine speed rises and the output current of the generator is consumed by each electric load via the B terminal, the rectifier operates as described above.
[0069]
FIG. 8 shows waveforms representing the generated voltage and current of the three-phase full-wave rectification for each phase, and waveforms representing the operation timings of the basic output signals VG1, VG2, and VG3.
[0070]
In FIG. 8, the change in the phase current of each phase is gradual compared to the steep change in the voltage of the U phase, V phase, W phase, and each phase. Therefore, the method of detecting the current of one phase and driving the remaining two phases based on the switching timing of the current is more accurate than the method of controlling the switching timing only by voltage detection. Can be switched.
[0071]
Therefore, the low-loss region of the power MOS transistor can be used effectively, and noise when the power MOS transistor is switched on and off can be reduced.
[0072]
Next, when the engine is stopped and the key switch 15 is turned off, the output of the NOR circuit 82 becomes “1”, and the rotation of the generator is stopped, so that the transistor 67 is turned off and the transistor 52 is turned off. Is turned off, the power supply voltage circuit that has generated VCC stops generating VCC.
[0073]
Since the power supply VCC no longer occurs, the low-potential-side power MOS transistor is turned off, and when the switches SW1, SW2, and SW3 are turned off, the high-potential-side power MOS transistor is also turned off. The unit stops operating.
[0074]
As a result, the dark current is minimized, and the discharge of the battery 14 when the engine is stopped can be minimized.
[0075]
In addition, although the above-mentioned example is an example in the case of rectifying three-phase alternating current, the present invention can rectify not only three-phase but also other multi-phase alternating current, and can obtain the same effect as the above-described example. Can do.
[0076]
In the case of multi-phase, the number of phases is set to n, k from 1 to n−1 with respect to the reference time T from when the current of one phase is detected and the polarity is inverted until the next polarity is inverted. If natural numbers are used, the transistors of the other phases are controlled to be turned on / off with a delay of T × 2 k / n from the time of the on / off operation control of the first phase transistor.
[0077]
【The invention's effect】
Since the present invention is configured as described above, the following effects are obtained.
That is, a standard power MOS transistor is used as a rectifying element, and only one-phase current of the rectifying device is detected to control the on / off operation of the one-phase power MOS transistor. According to the current detection, the power MOS transistor is controlled to be turned on / off at a predetermined timing.
[0078]
Therefore, the current detection means is only for one phase and is not required for the other phases, and it is possible to perform ON / OFF control of the power MOS transistor at the time when the phase current is the lowest while the configuration is simple and inexpensive. Therefore, it is possible to minimize heat generation during ON / OFF operation, and to suppress the occurrence of commutation surge generated by conventional P / N junction type diodes and to reduce noise. The rectifier can be realized.
[0079]
Of course, by using a power MOS transistor instead of a diode as a rectifying element, it is possible to suppress heat loss and realize a highly efficient rectifier for a charging generator at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a rectifier of a charging generator for a vehicle that is an embodiment of the present invention.
FIG. 2 is a circuit configuration diagram of the gate drive circuit shown in FIG. 1;
3 is a circuit configuration diagram of the gate drive circuit shown in FIG. 1;
4 is a circuit configuration diagram of the gate drive circuit shown in FIG. 1. FIG.
FIG. 5 is a circuit configuration diagram of the current detection circuit shown in FIG. 1;
6 is a circuit configuration diagram of the voltage control circuit shown in FIG. 1; FIG.
FIG. 7 is a signal timing chart of the rectification operation in one embodiment of the present invention.
FIG. 8 is a diagram showing operating voltage and current waveforms in an embodiment of the present invention.
[Explanation of symbols]
11 Armature Winding 12 Rectifier 13 Field Winding 14 Battery 15 Key Switch 16 Charging Warning Light 19 Flywheel Diode 21 Control Circuit 121, 125 P-Channel Power MOS Transistor 128 P-Channel Power MOS Transistor 122, 126 N-Channel Type power MOS transistor 129 N-channel type power MOS transistor 202 power MOS transistors 211 and 212 Gate signal generation circuit 213 Gate signal generation circuit 215 Current detection circuit 1201 Phase current detection shunt resistor

Claims (5)

A field winding that is rotated by the rotation of the engine to generate a rotating magnetic field, an armature winding that generates current by receiving the field winding, and a multiphase AC output generated in the armature winding is rectified. A multi-phase full-wave rectifier, and the multi-phase full-wave rectifier includes a series circuit of a high-potential side MOS power transistor and a low-potential side MOS power transistor for each phase. in the positive electrode side and the charging generator for the corresponding connected to the terminals and the ground side of the phase vehicle of the armature winding,
Current detecting means for detecting a phase current flowing in a terminal of at least one phase of the armature winding;
The polarity of the phase current of one phase detected by the current detection means is judged, and when the polarity is inverted, the reference signal of one phase whose output state is inverted to “1” and “0”, and this A reference signal of another phase whose output state is inverted to “1” and “0” is generated after a predetermined elapsed time from the time when the reference signal of one phase is inverted, and the reference signal of the one phase and Control means for controlling the on / off operation of the MOS power transistor provided for each phase based on the reference signal of the other phase ;
A rectifier for a charging generator for a vehicle. 2. The rectifying device for a charging generator for a vehicle according to claim 1, wherein the high potential side MOS power transistor and the low potential side MOS power transistor are different from each other from the reference signal of one phase and the reference signal of another phase. A control device for a vehicular charging generator , wherein the high-potential-side MOS power transistor and the low-potential-side MOS power transistor are each controlled to be turned on after being delayed by two delay times . The control apparatus for a charging generator for a vehicle according to claim 1 or 2, wherein n is the number of phases of the multiphase AC output, and k is a natural number up to 2 (n-1) / n , A vehicle charging generator for generating a reference signal of another phase, wherein a time obtained by multiplying a time from a reference signal inversion to a next polarity inversion by 2 k / n is set as the predetermined elapsed time . Control device. The control apparatus for a vehicle charging generator of claim 3, wherein the control device of the vehicular charging generator, wherein said multi-phase AC output is a three-phase ac output. 2. The control device for a charging generator for a vehicle according to claim 1, wherein each of the MOS power transistors is a trench type.

Images