JPS59172904A - Controlling method of electric rolling stock - Google Patents

Abstract

PURPOSE:To effectively utilize the torque of an induction motor to the maximum limit by calculating the torque by the rotating speed and current of the motor and stopping a variable voltage variable frequency inverter when the calculated result of the torque becomes zero. CONSTITUTION:An instruction unit 8 calculates torque T by the current CM and the rotating speed FM of an induction motor 4, and the torque T is compared with the set value TSET. When the torque T becomes smaller than TSET, a stop command is outputted to a variable voltage variable frequency inverter 3, and an open command is outputted to a switch 2. In this manner, the abrupt change of the torque when the inverter 3 is stopped can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for an electric vehicle that effectively utilizes the torque of an induction motor.

Figure 1 shows a conventional electric vehicle control method. In the figure,
(l) is a DC power supply, (2) is a switch, (3) is a variable voltage variable frequency inverter (hereinafter referred to as vvvy inverter), +41 is an induction electric brass machine (hereinafter referred to as engineering M), (5)
is the current detector that detects the current of the engineering M (4), (6) is the same wave number detector that detects the frequency of the engineering M (4), and (7) is the command (company) that detects the opening of the switch (2). It is configured to issue a command and a command to stop the VVVF inverter (3).

In Figure '71, when the switch (21) is closed and the Sobi inverter (3) is in operation, when stopping the VVVF inverter (3), the command unit (7) uses the comparator (7a) to Compare the current CM of (4) and its set value 0M day ET, and when the current CM is completely below the set value CMSET, or compare the frequency FM of comparator (7b) check M (4) and its set value FMSEiT. If the frequency FM is less than the set value FMSET, and the AND times bF
When r (7c) is in the regeneration state, when the regeneration command expires, the slow motion female (7d) issues the stop command of the VVVF inverter (81) and the open command of the switch (21) after a certain period of time. Then, set the current set value CMSET and frequency set value FMSET of 1M(4) to the same wave number FM as the current OM of M(4) where the torque disappears.
By combining K with K, the VVVF inverter fall is stopped after the torque becomes sufficiently small.

Here, the characteristic torque T1 magnetic flux Φ of the force M, the rotor current force R
, T= kl#1 ° 1inl +++++++
−＋＋＋＋＋ fi+1″ll [R1=kil
l#I・, /'5−−−−”−−−−−−i:ll. However, ■ is the motor voltage, f8 is the frequency,
fzmv and FM are the inverter frequency and motor rotor frequency, respectively.Here, when trying to determine that the torque T has become zero by detecting the motor current CM, CM is aM
=1. , + Is (iB is the exciting current), so the magnitude of the rotor current 1〒R1 is IIRI = ,
/IC river -1 engineering sl ----------
--- becomes n+. 11) According to the formula, j', l'R1 becomes zero, so the torque becomes 0. To find this condition from all measurable CM, the excitation current 1
Unless 181 is clear, 1Iu1 cannot be determined.

However, since 1Isl is proportional to the magnetic flux 1b1 in equation (2), it differs depending on the motor voltage and the inverter's wave number. Therefore, OMtf where the torque T becomes zero
i- cannot be determined logically. Similarly, if you try to find the motor rotation speed FMl at which the torque T becomes zero, (1) + 21
(From formula 31, torque T can be expressed as, but in this case, if fe becomes zero, the torque becomes zero. Also, s f8 = fxN
The value at which fe becomes zero cannot be uniquely determined from the FFs that can be measured from v-FM. According to the set value determined in this situation, ay is 0M8]l! ! When FM is below T or during regeneration, is FMSKT? When it falls below,
Since the torque is not necessarily small enough, [dfl
Since the VVVF inverter (3) and the switch (21) are stopped or cut off while l+ or braking torque remains, there is a drawback that the torque of the engine M cannot be utilized effectively to the maximum extent.

This invention was made in view of the above, and is a control method for an electric vehicle in which torque is calculated based on the rotation speed and current of the induction motor, and when the torque calculation result becomes zero, the variable voltage variable internal wave number inverter is stopped. I will provide a.

The figures will be explained below. In FIG. 2, 111~(
6) is the same as the conventional one, so its explanation will be omitted. (8) is #j
It is equipped with a calculator (8a) that calculates the torque T using the current CM and the rotational speed FM of the engineering M (41), and a comparator (8b) that compares the calculated torque T and the torque set value TSET. .

The one in Figure 2 calculates the torque T from the current CM and rotational speed FM of the machine M (4), and sets this torque T to the set value T8L.
When the torque T becomes smaller than T81nT compared to nT, the command device (8) issues a stop command to the VVVF inverter (3) and an open command to the switch (2). This prevents a sudden change in torque when the VVVF inverter (3) is stopped. In the above embodiment, the case where one machine M (4) is controlled is explained, but even when controlling a plurality of machines M+41t- , the torque T of the machine MI41 is calculated, and all the machine M(
When the torque T of 4) becomes zero, the vvVF inverter (3) is stopped and the switch (2) is fully opened, thereby making it possible to prevent torque unbalance between the two.

In addition, in regenerative operation, the regenerative power of M + 41 is v
When the loss is less than vvP'impark (3), it is no longer possible to regenerate electric power to the DC power supply +11, so regenerative braking has no effect as a vehicle brake. Therefore, at this time, it is necessary to completely stop the VVVF inverter (3) and shift to the air brake.

The regenerated power PM of the motor is expressed by the following equation.

PM = , /”r-v −cfl−−−−−−−−−
++++++HH- (61 motor voltage is determined by detecting the input voltage VFO of the VVVF inverter and controlling the modulation rate PMF of the V4VF inverter) v=pMy-vpc-------+++++++++++++
Since it is expressed as ++-(7), equation (6) is PM = , pressure・PMF・VFC! -OR------
−−−−−−−−+81 is formed into a diamond shape. According to this formula, the motor current OR, V which is being detected as a control element
The regenerated power of the motor can be calculated from the VVF inverter's manual pressure VFO. On the other hand, since the actual loss of a VVVF inverter can be measured in advance, the loss is compared with the regenerative power calculated above, and if it is below this, the
Stop the VVF inverter and quickly switch to the air brake. Thereby, the machine M can be stopped smoothly, and the regenerated power of the machine M can be utilized to the maximum.

According to this invention, the torque of the induction motor is calculated and the torque becomes zero or the regenerative power of the induction motor becomes vv.
By stopping the VVVF inverter when the loss is below the actual loss of the vr inverter, the electric motor can be operated efficiently over a wide range.

[Brief explanation of the drawing]

FIG. 1 is a conventional configuration diagram, and FIG. 2 is a configuration diagram according to an embodiment of the present invention. In the figure, (21 is a switch, (3) is a variable voltage variable, (4) is an induction motor, and (5) is a Current detector, I6) is speedometer generator, (8) is command device, (8a)
is a torque calculator. In addition, the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] Ill Induction controlled by a variable voltage variable frequency inverter: il! In a method of controlling an electric vehicle, the current and frequency of one motor are detected and the total torque of the induction motor is calculated, and the variable voltage variable same wave number inverter is stopped when the torque calculation result of the induction motor becomes zero. A control method for an electric car characterized by: (A method for controlling an electric vehicle according to claim 1, characterized in that a plurality of induction motors are controlled by 211 variable voltage variable frequency inverters. (3) Controlling by variable voltage variable frequency inverters. In the control method for an electric vehicle, in which the current of the induction motor is detected and the regenerative power of the induction motor is calculated, when the calculation result of the regenerative power is approximately equal to the loss of the upper variable voltage variable frequency inverter, the variable voltage A method for controlling an electric vehicle, comprising stopping a variable frequency inverter.