JPH11295332A - Speed detector - Google Patents

Abstract

(57) [Summary] An apparatus for detecting a speed by detecting a pulse from a PG attached to an electric motor for a railway vehicle is provided.
It is an object of the present invention to provide a speed detecting device which is not affected by manufacturing errors. An input unit (1) for detecting an edge of a pulse from a PG attached to a motor for a railway vehicle and outputting N pulses per rotation, and a signal input from the input unit (1). , PG, a decoder unit (2) for detecting a specific one of the N pulses input from the PG,
The reference clock output from the oscillator (3) is input, and N counters (4) for counting and counting, and the data of the counter (4) are latched by a signal output from the decoder unit, and the latched data is used as the speed calculation unit. This is a device for calculating the rotation speed of the electric motor from the count number of the reference clock (6) by transferring it to (5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed detector for detecting a speed by counting pulses output from a PG (pulse detector) attached to an electric motor for a railway vehicle.

[0002]

2. Description of the Related Art A conventional speed detecting device detects a pulse output from a PG attached to an electric motor and detects the speed from the number of pulses detected during sampling for a fixed time. The rotation speed of the electric motor is detected by using a method of detecting the interval of the motor and detecting from the time.

[0003]

However, pulses output from a PG rotating at a constant speed should be detected at regular intervals. May not be uniform.
As a result, the count number of pulses that can be detected within the sampling time is not uniform, or the interval between the edges of the pulse cannot be detected uniformly, and the accuracy of the speed detection result is not good. Further, in the conventional apparatus in which the speed calculation result when the speed of the motor changes is updated only at every sampling cycle, there is a problem that the speed response is not good. The present invention has been made in view of the above points, and aims to solve these disadvantages.
An object of the present invention is to provide a speed detecting device that improves the accuracy of a speed detection result and further improves a speed response.

[0004]

Means for achieving the object is to detect an edge of a pulse from a PG which is attached to a motor for a railway vehicle and outputs N pulses per rotation. An input unit, a decoder unit for detecting a specific one of N pulses input from the PG from the pulse signal detected by the input unit, and a reference clock signal output from the oscillator to input and count It is composed of N counters and a speed calculation unit which receives count data obtained by latching the data of the N counters by the edge of a pulse signal output from the decoder unit. With such a configuration, the N counters are sequentially switched at the rising edge of a pulse signal of one cycle from the decoder unit, and the latched count data is updated and transferred to the speed calculation unit, thereby achieving speed calculation. A speed detecting device configured to calculate a rotation speed of the electric motor from a count number of a reference clock in a section. Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0005]

FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 1 is a block diagram showing an edge of a pulse from a PG which outputs N pulses per rotation and is attached to a motor for a railway vehicle. An input unit 1 for detection is provided. Then, a decoder unit 2 for detecting a specific one pulse out of N pulses input from the PG from the signal input from the input unit 1 is provided. On the other hand, a counter 4 for counting the reference clock signal 6 output from the oscillator 3 is provided. here,
The counter 4 includes a plurality of counters 1 to N. The counter 4 latches the data of the reference clock in response to one pulse signal output from the decoder 2 and transfers the latched data to the speed calculator 5.

Next, a specific example of the speed detecting device having such a configuration will be described with reference to FIG. The counter 4 has the same number as the number of pulses output in one round of PG,
Separate counters (Counter 1 to Counter N) are provided. The clock output from the same oscillator 3 is input to the counter 4 as the reference clock signal 6. Each counter individually counts this reference clock signal 6.
The pulse signal input from the PG is converted from the counter 1 to the counter 2 to the counter 2 every time the pulse is input by the decoder unit 2 which detects a specific one pulse of the N pulses input from the PG. Switching. Switching of the counter from the decoder unit 2 is performed by designating the first counter when a pulse for one round of PG is input.

[0007] Every time the designation of the counter is switched, the decoder section 2 outputs a latch signal for counting the reference clock signal 6 to the switched counter. The counter 4 receiving the latch signal latches the count data,
The latched count data is transferred to the speed calculator 5.
The counter 4 clears the previous count data while transferring the count data to the speed calculation unit 5. Therefore, every time a pulse from the PG is detected, the corresponding counter transfers the count number of the reference clock 6 for one round of the PG to the speed calculation unit 5.

Now, assuming that the PG outputs 60 pulses per rotation in FIG. 2, when the rising edge of the first PG pulse is detected with respect to the input signal of the PG pulse, the decoder unit 2 outputs the latch signal. Is output. The counter 1 latches the counter 1 in the shaded area in response to the input of the latch signal 1 and starts transferring the data of the reference clock to the speed calculation unit 5. At this time, the counter 1 clears the count data that has been counting so far,
The counting of the reference clock signal 6 is started again. Thereafter, when the input unit 1 detects the rising edge of the second PG pulse of the PG pulse, the decoder unit 2 stops the transfer of the counter 1 to the counter 2 by the latch signal 2 and counts the counter 2 The transfer of the data to the speed calculation unit 5 is started. Thereafter, the count data from the counter 3 to the counter N is transferred to the speed calculation unit 5.

As a result, each counter counts the reference clock signal 6 for one rotation starting from the pulse of the PG shifted by one pulse from the previous counter. The speed calculation unit 5 can calculate the rotation speed of the motor or the frequency of the motor from the count number of the reference clock signal 6 written from the counter and the frequency of the reference clock signal 6.

[0010]

As described above, according to the present invention, P
Since the counter data during one rotation of a specific one of the N pulses input from G is taken in,
There is no influence on speed data due to pulse waveform errors due to the fabrication of G. In addition, by providing a counter for each pulse of the PG, when used for a PG that outputs N pulses per rotation, the speed calculation data for N rotations per rotation of the electric motor is represented by the speed Updated by the arithmetic unit. Therefore, unlike the speed detection by sampling for a fixed time in the conventional method, the speed data is updated at any time without being affected by the sampling time.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of the present invention.

FIG. 2 is a timing chart of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input part 2 Decoder part 3 Oscillator 4 Counter 5 Speed calculation part 6 Reference clock

Claims (1)

[Claims] Claims: 1. An electric motor for a railway vehicle,
An input unit for detecting the edge of a pulse from a PG that outputs N pulses per rotation, and a specific one of the N pulses input from the PG from a pulse signal detected by the input unit. A decoder unit for detecting, and a reference clock signal output from the oscillator, input and counted.
And a speed calculation unit which receives count data obtained by latching the data of the N counters by the edge of the pulse signal output from the decoder unit, and the rising edge of a pulse signal of one cycle from the decoder unit In this manner, the N counters are sequentially switched, and the latched count data is updated and transferred to the speed calculation unit, whereby the speed calculation unit calculates the rotation speed of the electric motor from the count number of the reference clock. A speed detecting device characterized by the following.