JP2524846B2 - In-vehicle power supply protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a vehicle-mounted power supply device using a generator and an inverter, and determines whether or not the power supply device itself fails when the power supply device is stopped. The present invention relates to a protective device for a vehicle-mounted power supply device having a determination function.

(Prior Art) As a vehicle-mounted power supply device for a car driven by an engine, there is a device that takes out a PTO shaft from a car running engine, drives a generator, and converts the obtained electric power into a constant frequency by an inverter. . FIG. 3 is a block diagram showing an example of this device. In the figure, 1 is an engine, 2 is a PTO shaft, and 3
Is a generator, 4 is a voltage control device, 5 is an inverter, 6 is an inverter control device, 7 is a protection device, and 8 is an electrical load.

In this device, even if the rotation frequency of the engine 1 changes and the frequency of the electric power of the generator 3 changes, it is converted into AC power of a constant frequency by the inverter, so that high-quality electric power can be obtained. In addition, maintenance can be performed without providing a separate engine for power generation.

Since the user connects an arbitrary electrical load 8, the protection device 7 is provided to protect the system so as not to overload the device. Items of protection include overcurrent, overvoltage, overload, and reduction in rotation speed.

FIG. 4 is a detailed block diagram showing an example of the conventional protection device 7. In the figure, 71 is an overcurrent detector that detects an overcurrent, 72 is an overvoltage detector that detects an overvoltage, 73 is an overload detector that detects an overload, and 74 is a rotation speed decrease detector that detects a decrease in rotation speed. , 75 is a latch circuit for holding an abnormal signal,
Reference numeral 76 is a run / stop circuit that generates a signal for stopping the device. The signal N is a rotation speed signal, I is a current signal, and V is a voltage signal.

In the protection device 7 of FIG. 4, the signals detected by the detectors 71 to 73 have a high probability of being caused by a failure of the load or the device, and the signals disappear when the operation is stopped. When is detected, the latch circuit 75 holds the signal and continues the operation. Also, if the rotation speed falls below a certain level, the generator will be overloaded and it will not be able to operate, but this reduction in rotation speed is more likely than other causes than equipment failure, such as during deceleration due to engine braking, Detector
The output of 74 is input to the operation stop circuit 76 without passing through the latch circuit 75, and the operation is also restored when the rotation speed is restored.

(Problems to be Solved by the Invention) According to the vehicle-mounted power supply device that is driven as described above, high-quality electric power is obtained on the vehicle and no particular maintenance is required. Therefore, it is about to be used for various vehicles. . Along with that, the operation pattern and the electric load 8 are also various. For example, when a refrigerator compressor motor is used as a load, the motor is independently turned on and off by the temperature controller of the refrigerator. When the motor is on, a rush current flows through the in-vehicle power supply device, and when it is off, the voltage rises due to the control delay of the voltage control device. Further, the delay of the voltage control device causes a voltage increase while the engine speed is increasing and a voltage decrease while the engine speed is decreasing.

This is shown in FIG. The point A in the figure is the motor OFF
When the increase in the rotation speed and the increase in the rotation speed occur at the same time, the voltage increases significantly. At point B, the inrush current is large because the voltage is high when the motor is turned on when the voltage increases due to the increase in rotation speed.

Such overlapping of adverse conditions is quite rare, but in the conventional device, once the protection is activated, the vehicle-mounted power supply device is stopped. Therefore, in order to prevent the protection device from operating and stopping, the ratings and capacities of the components of the power supply device are increased to give a margin, and the protection level is raised to prevent the device from operating. On the other hand, a semiconductor switch is used for the inverter 5 of the in-vehicle power supply device, but since the semiconductor switch has a small overload withstand capacity, the current capacity is about 10 times the normal current and the withstand voltage is about 3 times. Need elements,
The external dimensions of the device were large and the price was high.

An object of the present invention is to automatically determine, when an abnormality is detected and the in-vehicle power supply device is stopped, whether the power supply device has a failure or a failure due to other circumstances, and if the power supply device is not a failure, continue the operation as it is. It is an object of the present invention to provide a protection device for a vehicle-mounted power supply device that enables the above.

[Structure of Invention]

(Means for Solving the Problem) Even when the power supply device protection device for a vehicle according to the present invention detects an abnormality and stops the power supply device, the power supply device is restarted after a predetermined time, and the power supply device is normal at that time. For example, if the abnormality is detected, the operation is continued, and if an abnormality is detected, the operation is stopped and restarted again after a predetermined time. It is characterized by

(Operation) In the present invention, when an abnormality is detected by the above means, it is automatically determined whether the power supply unit is in failure or due to other circumstances, and if the power supply unit is not in failure, the operation is continued as it is. can do. As a result, stable operation can be continued even if the capacity rating of the parts constituting the power supply device, especially the semiconductor switch, is kept small, so that the power supply device can be downsized and the cost can be kept low.

(Embodiment) First, FIG. 1 showing an embodiment of a protection device for a vehicle-mounted power supply device of the present invention will be described. In FIG. 1, the same reference numerals as those in FIG. 4 indicate the same components. Reference numeral 77 is a first timer circuit that resets the latch circuit 75 at a predetermined first set time after abnormality detection, and 78 counts the number of abnormality detections and outputs a power supply unit failure signal when the count exceeds the predetermined number. A counting circuit 79 is a second timer circuit that clears the count value of the counting circuit 78 after a predetermined second set time has elapsed since the first abnormality.

Next, a method of protecting the on-vehicle power supply device of the present invention will be described. For example, when the occurrence of overcurrent is detected, the latch circuit 75 holds the signal and stops the vehicle-mounted power supply device. Since the abnormal signal disappears when the device stops, the device restarts operation if the first timer circuit 77 resets the latch circuit 75 after a predetermined first set time. If no abnormality is detected after restarting the operation, the operation is continued as it is.

The count value "1" of the counting circuit 78 is cleared to "0" after the second set time set by the second timer circuit 79. If an abnormality is detected again after the operation is restarted, the count value of the counting circuit 78 becomes "2", and the operation is stopped in the same procedure as the first time. Next, within the second time of the second timer circuit 79 from the first abnormality detection,
When an abnormality is repeatedly detected, the count value of the counting circuit 78 increases, and when it reaches a predetermined number of times, it is determined that the power supply device has failed, and a failure signal is output to the operation / stop circuit 76. Once the failure is determined, the in-vehicle power supply device is not restarted and the stop is continued.

As described above, in the protection device of the present invention, even if the bad condition overlaps among various operation patterns and the protection of the power supply device is activated, the protection device is automatically restarted, depending on the failure of the vehicle-mounted power supply device or other situations. If it is not a failure of the power supply device, the operation can be continued as it is, and if it is a failure of the power supply device, the operation can be stopped. Frequently, the vehicle is decelerated by engine braking, the number of revolutions is reduced, and the power supply device is stopped. Therefore, it is rare that the bad condition will be stopped and the problem will not occur.

In the above description, the protective device is the detectors 71 to 74, the latch circuit 75, the operation stop circuit 76, the first timer circuit 77, the counting circuit 78.
Although the method of forming the second timer circuit 79 by an independent circuit has been shown, the invention is not limited to this. As shown in FIG. 2, the rotation speed signal N, the current signal I, the voltage signal V, etc. are A / D. The same effect can be obtained even if the converters 101, 102, 103 convert the digital amount and read it into the microcomputer 104 to perform the same processing by software.

〔The invention's effect〕

As described above, in the in-vehicle power supply device protection device of the present invention, even if an abnormality is detected and the protection device operates to stop the power supply device, it is automatically restarted to determine whether or not the power supply device has failed. If it is not a failure, it is possible to continue operation.

Therefore, unlike the prior art, it is not necessary to make the capacity of the constituent parts of the power supply device very large so that protection does not work under conditions other than failure. As a result, the operation can be stably continued even if the capacity of the semiconductor switch is suppressed to a small value, so that the power supply device can be downsized and the cost can be suppressed to a low value.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a protection device for an on-vehicle power supply device of the present invention, FIG. 2 is a block diagram showing another embodiment of the present invention, and FIG. 3 is a block diagram showing a configuration of the on-vehicle power supply device,
FIG. 4 is a block diagram showing an example of a conventional on-vehicle power supply protection device, and FIG. 5 is a waveform diagram for explaining an operating condition of the on-vehicle power supply device. 1 ... Engine, 2 ... PTO shaft, 3 ... Generator, 4 ...
Voltage control device, 5 ... Inverter, 6 ... Inverter control device, 7 ... Protection device, 8 ... Electrical load, 71 ... Overcurrent detector, 72 ... Overvoltage detector, 73 ... Overload detection Device, 74 ... Rotation speed drop detector, 75 ... Latch circuit, 76 ...
… Run / stop circuit, 77 …… first timer circuit, 78 …… counting circuit, 79 …… second timer circuit

 ─────────────────────────────────────────────────── --- Continuation of the front page (56) References JP-A-56-118101 (JP, A) JP-A-62-278642 (JP, A) JP-A-1-314347 (JP, A) JP-A-60- 167699 (JP, A) JP 61-185097 (JP, A) JP 62-267806 (JP, A)

Claims (1)

(57) [Claims] 1. A generator driven by a vehicle running engine, a voltage controller for controlling the voltage of the generator, an inverter for converting the output of the generator into electric power of a predetermined frequency, and the inverter. In an in-vehicle power supply device including an inverter control device for controlling the inverter control device and a protection device for the inverter control device, the protection device includes a detector that detects an abnormal signal of the in-vehicle power supply device, and a latch circuit that holds the abnormal signal. A first timer circuit that clears the signal of the latch circuit after a predetermined first set time from the occurrence of an abnormality, and a counting circuit that counts the number of detections of the abnormality and issues a failure signal when the predetermined number of times is reached, A second timer circuit that clears the count value of the counter circuit after a predetermined second set time that is at least twice the first set time from the first occurrence of the abnormality; And a latch circuit and said inverter control unit controls the in-vehicle power supply apparatus driving and stopping circuit for operating and stopping the presence or absence signal of the counting circuit,
Even if the vehicle-mounted power supply device is stopped when an abnormality is detected, the vehicle is restarted after the predetermined first set time, if the abnormality is not detected, the operation is continued, and if the abnormality is detected, the vehicle-mounted power supply device is stopped again. Then, the vehicle is restarted a plurality of times so as to be restarted after the predetermined first set time, and if an abnormality is detected a predetermined number of times within the predetermined second set time from the first abnormality detection, the vehicle is mounted. A protective device for an in-vehicle power supply device, characterized in that the in-vehicle power supply device continues to be stopped without being restarted upon judging that the power supply device has failed.