JPH0226220A - Controller for dc elevator - Google Patents

Abstract

PURPOSE:To suppress an abrupt overvoltage due to the trouble of a power converter and to protect the converter by interruption by providing a second energy absorbing element and an overvoltage detector at the output terminals of a rectifier provided at an AC side. CONSTITUTION:Power from a power source 15 is rectified by a power converter 1, and supplied to a DC motor DCM. A rectifier 2 is connected to the AC terminal of the converter 1, and a second energy absorbing element 4 and an overvoltage detector 5 are connected to the output of the rectifier 2. Further, the output terminal of the rectifier 2 is connected to the output terminal of the converter 1 through a diode. A predetermined voltage is charged in the element 4 by a charger 11. The element 3 absorbs a current at the time of a trouble to raise its voltage, and if it exceeds a specified value, the current is absorbed to the element 4. Thus, when the voltage rises, the converter 1 is interrupted by the operation of the detector 5.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power converter for an elevator, and particularly to a control device suitable for controlling the speed of a DC elevator using a DC motor as a drive motor.

[Conventional technology]

The first power converter of the armature circuit in JP-A No. 58-82973 uses PWM (pulse width modulation) control, but in the first power converter configured with such a current cutoff function element, the power supply side It is important to handle the voltage generated by the stored energy in the leakage inductance.

One of the methods is published in the Journal of the Institute of Electrical Engineers of Japan 61-1389. This method absorbs the energy of the leakage inductance and regenerates it into the power supply, which has the problem of requiring a large capacity regeneration circuit, making it economically impractical.

[Problem to be solved by the invention]

The above-mentioned conventional technology has problems such as not being able to handle high voltage due to leakage inductance on the power supply side and energy stored in circuit inductance using economically superior means.

SUMMARY OF THE INVENTION An object of the present invention is to provide a DC elevator control device with excellent performance and economy.

[Means to solve the problem]

The PWM transistor converter, which is the first power converter of the armature circuit, has a first energy absorbing element and a rectifier on the AC side, a second energy absorbing element and an overvoltage detector at the output end of the rectifier, and a second energy absorbing element and an overvoltage detector on the output end of the rectifier. Connect to the output terminal of the transistor converter with a diode. If a non-conducting failure occurs in the semiconductor elements that make up the converter, a current path consisting of a rectifier, a second energy absorption element, and a diode is formed to control the occurrence of steep overvoltage, and at the same time, an overvoltage detector detects the overvoltage. .

The overvoltage signal from this overvoltage detector shifts the base current of the converter main circuit transistor, and at the same time activates the stored energy release circuit of the armature winding inductance of the DC motor and the externally inserted DC inductance, making it economical. It is possible to provide a DC elevator control device with excellent performance and high reliability.

[Effect]

As shown in FIG. 1, the first energy absorption element 3 reduces sudden changes in the power supply current that occur when the current is turned on and off due to the PWM pulse operation of the transistor, and absorbs the energy accumulated in the leakage inductance on the power supply side to increase the energy consumption. It acts to control the generation of voltage.

The rectifier 2 and the second energy absorption element 4 are connected to the first power converter 1
bypasses the current when a non-conducting fault occurs in the transistor, creates a current path to the second energy absorption element 4,
The steepness has the effect of suppressing high voltage generation.

The overvoltage detector 5 detects that the voltage of the second energy absorption element exceeds a predetermined value, cuts off the drive signal of the first power converter, and at the same time short-circuits the output end of the first power converter to connect the DC reactor. DCL acts to release the energy of the internal inductance of the DC motor.

〔Example〕

FIG. 1 shows an embodiment of the present invention, and FIGS. 2 and 3 are explanatory diagrams of the present invention.

In FIG. 1, the power contact 12 is closed and the power converter 1 is connected to the power source 15. PW of transistor of power converter 1
M (Pulse Width Modulation
) Converts AC power to DC power by chopping operation, and connects DC motor DC through DC inductance DCL.
It supplies DC power to M. Transistor P
During WM chopping operation or a non-conducting failure, high voltage is generated by the energy stored in the leakage inductance 16 on the power supply side, the DC inductance DCL, the inductance of the DC motor DCM, etc., and there is a risk of destroying the semiconductor element. Therefore, the first energy absorbing element 3 reduces the current change on the power supply side during the PWM chopping operation of the transistor, absorbs the energy stored in the leakage inductance 16, and controls high voltage generation. The high voltage that occurs when a transistor fails to conduct is suppressed by the circuit shown below.

A rectifier 2 is connected to the AC end of the power converter 1, and a second energy absorption element 4 and an overvoltage detector 5 are connected to the output of the rectifier 2. Further, the output end of the rectifier 2 and the output end of the power converter 1 are connected through a diode. The second energy absorbing element 4 is charged with a voltage of a predetermined value by a charging circuit 11 with a polarity as shown in the figure. Next, the operation of suppressing overvoltage will be explained using FIGS. 2 and 3.

For example, when the transistors UP and VN turn on, the current υ
P is transistor UP, DC inductance DCL,
The current flows through the path of the motor DCM, the transistor VN, the power supply inductance 16, and the power supply 15. Next, when transistor Up is turned off and transistor Wp is turned on, current commutates from transistor UP to transistor Wp. During this commutation operation, the current flowing through the leakage inductance 16 on the power supply side suddenly changes, so that a high voltage ΔV is generated due to the energy stored in the leakage inductance 16 on the power supply side.

Therefore, by connecting the first energy absorbing element 3 to the AC side of the power converter 1, the current flowing through the leakage inductance 16 on the power supply side is made to flow through the first energy absorbing element 3 as a current 'IC', and the sudden change in the current High voltage ΔV can be achieved by reducing
' can be sufficiently suppressed.

By the way, if a failure occurs in which the transistor becomes non-conductive,
A high voltage is generated by the energy stored in the leakage inductance 16 and the DC inductance DCL on the power supply side. Therefore, a rectifier 2 is placed on the AC side of the voltage converter 1, a second energy absorption element 4 is placed on the output of the rectifier 2, a voltage detector 5 detects the voltage of the second energy absorption element 4, and the detection signal is used to create a DC inductance DCL, , a circuit 1o that releases the stored energy of the DC motor DCM and a circuit that stops the operation of the power converter 1 are provided.

When a failure occurs in which the transistor Wp becomes non-conductive, the leakage inductance 16 and the DC inductance DCL on the power supply side
, and the current Iwp tries to continue flowing due to the inductance of the motor, but since the current path is cut off, the current Ic flows through the first energy absorbing element 3, and the voltage ΔVc of the first energy absorbing element 3 continues to rise. . When the voltage ΔVc becomes higher than the initial setting voltage VBI of the second energy absorbing element 4, the diode D1. A current IWP' flows through the path between the second energy absorbing element 4 and the diode D2.

At this time, the energy of the circuit inductance is absorbed by the second energy absorbing element 4, and the steepness suppresses the generation of voltage Va. A predetermined value VD of this voltage is detected by the voltage detector 5, and when the predetermined value is exceeded, the energy release circuit 1o is activated to release energy from the DC inductance DCL and the armature DCM of the motor, and at the same time, the power converter 1 to protect the power converter.

〔Effect of the invention〕

According to the present invention, even if a non-conducting fault occurs in a transistor of a power converter, the second energy absorbing element can suppress the occurrence of a steep overvoltage, and the voltage of the second energy absorbing element can be detected and the power converter can be operated. The power converter can be protected by blocking the drive signal of the motor and simultaneously releasing the energy of the DC inductance DCL and the armature DCM of the motor.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, and FIGS. 2 and 3 are explanatory diagrams of the present invention. 3... first energy absorption element, 2... rectifier, 4...
...Second energy absorption element, 5...Overvoltage detector, I
)z...diode, 1o... shorting element.

Claims (1)

[Scope of Claims] 1. A control device for a DC elevator including a power converter that converts AC power into DC power and supplies power to an armature of the DC motor, and a DC motor for driving an elevator, wherein the power converter comprises: A first energy absorbing element and a rectifier are provided at the AC end, a second energy absorbing element and an overvoltage detector are provided at the output end of the rectifier, and the output end of the rectifier and the output of the power converter are connected via a diode. A control device for a DC elevator, comprising: a short-circuiting element that cuts off a drive signal for the power converter based on a signal from the overvoltage detector and short-circuits an output end of the power converter. 2. The control device for a DC elevator according to claim 1, wherein the second energy absorbing element is provided with an initial charging circuit.