JPH02179202A - Discrimination between regeneration and power running in electric rolling stock - Google Patents

Abstract

PURPOSE:To contrive to speed up the discrimination between regeneration and power running by bringing a regeneration-power running change-over contactor temporarily to a power running state at the time of discriminating between regeneration and power running and by checking a plugging current at that time. CONSTITUTION:Directly after an accelerator ACC is stepped on, motor field winding change-over means MF, MR are changed and connected to a specific polarity by polarity indication switch input means DF, DR, a regeneration-power running change-over means MG is temporarily changed and connected to the power running side, and thereafter a normal power running control pulse is given to a running chopper. Then, a decision is given on regeneration, when a plugging current exceeds a specified level at the time of said chopper being turned OFF. When no decision on regeneration is not given for the period from the first pulse to several pulses, the decision is given on power running. Thus, it is possible to discriminate between regeneration and power running instantly only by detection of the plugging current.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for determining regeneration/power running in an electric vehicle such as a battery forklift.

[Prior Art] Generally, electric vehicles such as battery-powered forklifts are equipped with means for switching between regeneration and power running, and when starting an electric vehicle, it is necessary to determine whether the state is regeneration or power running. ing.

Therefore, when the accelerator is first stepped on, the contact of the regeneration/powering switching means provided in the motor circuit is first set to the regeneration Ill (open side), and the traveling chopper that controls the drive of the motor is turned on. When a pre-excitation current is applied to the ONL and the field winding of the motor, the armature current at that time differs depending on the rotational direction of the motor.
It is designed to distinguish between regeneration and power running.

To explain this conventional method for determining regeneration/power running using FIG. 2, the armature A of the motor switches its polarity with a regeneration/power running switching contactor MG, an armature current detection resistor Ra, and a field winding W. The switching contactor MF and the MR1 are connected to the battery BA via the running chopper CH, but for the determination operation, the contactor MG is initially opened, and the pre-excitation circuit element TR and the running chopper CH are turned on.

As a result, a pre-excitation current Isf flows through the field winding W,
At that time, if the motor is rotating in the reverse direction, the induced voltage E in the S R element A will be in the right direction in the figure, and this induced voltage E will cause the generated current of 1 g to flow through the closed loop circuit consisting of the running chopper CH and the regenerative diode Dg as shown by the arrow. flows.

This is detected by the t-current detection resistor Ra, and if the generated current exceeds a certain level of 1 g, it is determined that regeneration is occurring. On the other hand, if the motor is not rotating in the reverse direction, the induced voltage E will be in the left direction, so the generated current Ig will not flow, and power running is determined.

When it is determined that power running is being performed, contactor MG is closed.

[Problems to be Solved by the Invention] By the way, in the above determination method, the pre-excitation period is approximately 100 minutes to perform the regeneration/power running determination after stepping on the accelerator.
Further, when it is determined that the power running is performed, an operation time of approximately 100 m5 is required to close the contactor MG. Therefore, it takes a total of 200m5 to accelerate the power running.
There is a time loss, resulting in poor acceleration response. In this respect, it is desired to improve the driving functions of electric vehicles such as forklifts.

The present invention is in response to the above-mentioned demands, and aims to provide a method for determining regeneration/power running of an electric vehicle that speeds up the regeneration/power running discrimination operation and improves the accuracy of regeneration discrimination.

[Means for Solving the Problems] The present invention includes a DC motor, a switching means for switching the polarity of the field winding of the motor, and a switching means for switching between regeneration and power running in series with the armature of the motor. , a plugging diode that allows the plugging current to flow to the armature during reversal of power running, a flywheel diode that returns the energy stored in the inductance of the motor to the power supply, and duty control of energization to the motor during regeneration and power running. a regenerative diode for flowing regenerative current during regeneration, an accelerator input means for detecting when the accelerator is depressed, a switch input means for instructing forward/reverse polarity, and a regenerative chopper for controlling the armature current of the motor. An armature current detector for detecting, a plugging current detector for detecting the plugging current flowing only during reverse rotation, a switching means for switching the polarity of the field winding, a regeneration/powering switching means, and a control for controlling pulses of the traveling chopper. Immediately after stepping on the accelerator, the field winding switching means of the motor is switched to a predetermined polarity by the polarity indicating switch input means, and the regeneration/powering switching means is temporarily switched to the powering side. After the switching connection is made, a normal powering control pulse is applied to the running chopper, and if the plugging current at the time when the chopper is turned off is above a predetermined level, regeneration is determined, and the regeneration/powering switching means is switched to the regeneration side. Furthermore, the period from the first pulse to several pulses is defined as a determination period, and if regeneration is not determined within this period, powering is determined, and the regeneration/powering switching means changes the state of the powering side. This is a regeneration/power running discrimination method that continues the power running control.

[Operation] According to this determination method, immediately after stepping on the accelerator, the motor circuit is assumed to be in the same state as in normal power running, and the motor circuit is in the same state as in normal power running, and the motor circuit is in the OFF state immediately after supplying the ON pulse of the running chopper, which is the same as in normal power running.
During the period, when the regenerative motor is reversed, one lagging current flows through the plugging diode due to the induced voltage of the armature. Therefore, regeneration and power running can be immediately determined by simply detecting the plugging current.

[Example] Hereinafter, an example of the circuit configuration of an electric vehicle in which the method of the present invention is implemented will be described with reference to FIG.

The armature A of the DC motor that serves as the driving source for the electric vehicle is:
Contactor MG (switching means) that switches between regeneration and power running
further connected in series with the field winding W of the motor and
Forward and reverse contactor M that switches the polarity of its windings
P, MR, and the battery BA via the driving chopper CH, etc., which controls the duty of energizing the motor during regeneration and power running.
Connected to (@source).

Additionally, a plugging diode DP is provided so that a plugging current flows through the armature A when the motor runs in power or reverses, and a flywheel diode Df is provided to return energy stored in the inductance of the motor to the power source.
and a regenerative diode Dg for flowing regenerative current during regeneration.
is provided.

Directional switches DF and Drt for instructing forward and reverse polarity are connected in series with the coils MF and MR that drive the contactors MP and MR, respectively, and further,
Battery B is connected to the battery B via the microswitch SF, which is turned ON when the accelerator ACC is not in neutral, and the control transistor Q1.
Connected to A. Further, a coil MG that drives the contactor MG is connected to the battery BA via the microswitch SF and the control transistor Q2.

When the accelerator ACC is depressed, the accelerator angle data AD output in accordance with the amount of depression, the armature current detection resistor Ra inserted in series with the armature A, and the plugging current inserted in series with the plugging diode Dp. Each data Ia and Ip from the one running current detection resistor Rp to be detected is input to a control circuit CC (control means),
The outputs G, Bfr, and Bg of the control circuit CC control the traveling chopper CH and the transistors Q1 and Q2.

In the above configuration, immediately after stepping on the accelerator ACC, as shown in FIG. 3, the control circuit CC temporarily turns on the same state as the normal powering state, that is, the forward contactor MF and the regeneration/powering switching contactor MG. Then, the same ON pulse as in normal powering is supplied to the running chopper CH.

As a result, battery current rb flows from battery BA to armature A. OF immediately after supplying this ON pulse
When the motor is reversed during regeneration during period F, armature A
An induced voltage E is generated in the right direction in the figure, and therefore, a plugging current Ip is generated in a closed loop consisting of the plugging diode DP and the contactor MG (closed) as shown by the broken line.
flows.

Therefore, by checking whether or not this plugging current ρ exceeds a predetermined level within a predetermined determination period (described later), if it exceeds it, regeneration is determined to be possible, contactor MG is opened, and regeneration control is performed. On the other hand, if the plugging current hp does not exceed the predetermined level within the predetermined determination period, power running is determined and power running control is continued.

The above regeneration/power running discrimination operation will be explained below based on the time chart of FIG. 4.

In the same figure, by stepping on the accelerator ACC, the ON pulse G for the running chopper CH is 4 m from the control circuit CC.
It is output at a constant period of S, and in synchronization with it, 1! is output during the ON period of pulse G! During the OFF period of the armature current Ia, the excitation current If and the plugging current ip flow as shown in the figure, and here, since the plugging current 1p exceeds a predetermined level immediately after the third pulse G, regeneration is determined. Based on this judgment, the contactor MG contact is separated so as to become an oven, but during the time required for this separation, approximately 8 mS, the pulse G
is locked.

Note that the regeneration/power running discrimination period is a certain period of time, for example, 16 mS at maximum, immediately after stepping on the accelerator ACC, and thereafter, control is performed based on the determination result, that is, regeneration or power running is controlled. Further, if a regeneration determination is made within the above-mentioned determination period, the determination period is ended at that point.

Next, if the relationship among the armature current 1a, plugging current IP, and excitation current If is shown in the formula, 1 = 1 + 1 pr for the period when the running chopper CH is OFF, and if the motor is not reversed, I = O. For,
I = If, and if reverse rotation (regeneration possible), ■ ≠ 0, and the plugging current I is the armature induced ρ
p is proportional to the voltage E, I -E/rA where rA is the resistance of the armature, and the induced voltage E is: E=kIfN where k is the proportionality constant and N is the rotation speed, so the plugging current Ip is The plugging voltage IIρ is proportional to the rotation speed, and therefore exceeds a predetermined level after one pulse during high-speed reversal, two to three pulses during medium-speed reversal, and three to four pulses during low-speed reversal.

Thus, if the pulse period is 4 mS, then 4 to 16 m
It can be determined within 4 mS, and especially during high-speed reverse rotation where an immediate deceleration response is required, it can be determined within 4 mS. Since the detachment time of the contactor contact is 8 mS,
The regeneration switching time in high-speed reversal is 4 + 8 = 12 mS, and the maximum regeneration switching time in low-speed reversal is 16 + 8 = 24 mS, which is much shorter than the 200 m5 required by the conventional method, making it easier to use in actual regeneration switching. Above, you will hardly notice any delay in response.

Moreover, in the case of power running acceleration, there is no delay time at all,
This provides extremely responsive control for electric vehicles.

Furthermore, since the plugging current ip does not flow except during reverse rotation, it is possible to make reliable discrimination in addition to the conventional method of discrimination based on the armature current 1a. Further, according to the present method, there is no need to flow a preliminary excitation current through the field winding at the time of discrimination as in the conventional method, so that discrimination can be performed with a simple configuration.

[Effects of the Invention] As is clear from the above explanation, according to the method of the present invention, when determining regeneration/powering, the regeneration/powering switching contactor is temporarily put in the powering state, and the 1 lagging @flow at that time is checked. Since regeneration and power running are determined by the above, it is possible to make a determination within a few pulses of the running chopper.Especially, when power running is determined, it is sufficient to continue in the state of discrimination operation. In the method of checking the armature current by pre-exciting the regeneration/power running contactor as an oven, not only does it take a long time to pre-excite, but also when power running is determined, the contactor contact closes after the determination, which takes a long time to respond to the operation. In contrast, with the method of the present invention, the determination time is greatly shortened and responsiveness is improved.

Further, since the plugging current does not flow except when the motor is reversed, the accuracy of determination is improved and the configuration can be simplified compared to the conventional method of checking the armature current by preliminary excitation.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an electric vehicle in which the method of the present invention is implemented;
Figure 2 is a circuit diagram for explaining the operation of the conventional method;
The figure is a circuit diagram for explaining the operation of the method of the present invention, and FIG. 4 is a time chart for explaining the operation of the method of the present invention. A...Motor armature, W...Motor field winding,
MF', MR...Polarity switching contactor, MG...Regeneration/powering switching contactor, Dp...Plugging diode, Df...Flywheel diode, Dg...
・Regenerative diode, CH...travel chopper, ACC・
...Accelerator, DF, DR...Directional switch, Ra...Armature current detection resistor, Rp...Plugging current detection resistor, CC...Control circuit, BA...
Battery. Applicant Nippon Yusoki Co., Ltd. Agent Patent Attorney Yasushi Itatani (Conventional) Daikoku (Tohatsuro)

Claims (1)

[Claims] (1) A DC motor, a switching means for switching the polarity of the field winding of this motor, and a regenerative motor connected in series with the armature of the motor.
A plugging diode is provided to switch between power running and the plugging current flows to the armature during reversal of power running, a flywheel diode is used to return the energy stored in the inductance of the motor to the power supply, and a plugging diode is provided to switch between power running and power running. A travel chopper that controls the duty of energizing the motor, a regeneration diode that causes regenerative current to flow during regeneration, an accelerator input device that detects when the accelerator is pressed, and a switch input device that instructs forward/reverse polarity. An armature current detector that detects the armature current of the motor, a plugging current detector that detects the plugging current that flows only during reverse rotation, switching means for switching the polarity of the field winding, regeneration/powering switching means, and running In an electric vehicle equipped with a control means for controlling chopper pulses, immediately after stepping on the accelerator, the field winding switching means of the motor is switched to a predetermined polarity by the polarity indicating switch input means, and the regeneration/power running is switched on. After the switching means temporarily switches to the power running side, it applies a normal power running control pulse to the traveling chopper, and if the plugging current at the time when the chopper is turned off is equal to or higher than a predetermined level, regeneration is determined,
The regeneration/power running switching means is switched to the regeneration side, and the period from the first pulse to several pulses is set as a determination period, and if regeneration is not determined within this period, power running is determined, and the regeneration/power running switching means is switched to the regeneration side. A method for determining regeneration/powering in an electric vehicle, characterized in that the powering switching means continues a powering side state and continues powering control.