JPH07337032A - Phase current detection system for inverter controller - Google Patents

Abstract

PURPOSE:To enhance the safety of an inverter controller by providing an individual power supply for each phase current detecting Hall CT and a phase current imbalance detecting circuit for detecting abnormality in the power supply for the phase current detecting Hall CT. CONSTITUTION:Power supplies 41-43 are provided individually for respective phase current detecting Hall CTs. When one or more than one of the power supplies 41-43 fails arbitrarily, input currents To1, Io2, Io3 to a phase current imbalance detecting circuit 5 do not satisfy the balance theory and thereby imbalance of phase current is detected. Consequently, a gate pulse generating logic circuit 9 delivers a PL for interrupting the thyristor of each phase to a gate driver 11 which then delivers an output PD for interrupting the operation of thyristor of each phase. This constitution suppresses divergence of control system thus enhancing the safety of an inverter controller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase current detection system in an inverter control device used for controlling an induction motor.

[0002]

2. Description of the Related Art FIG. 3 shows a phase current detection system in a conventional inverter control device.

A conventional phase current detection system of an inverter control device is a Hall CT for detecting a first phase current, a hall CT for detecting a second phase current, a hall CT3 for detecting a third phase current, and these phase current detections. Common power supply for hall CT, phase current imbalance detection circuit 5, effective value calculation circuit 6, current command software 7, power main converter 8, gate pulse generation logic circuit 9, and phase current imbalance detection circuit 5, an effective value calculation circuit 6, a current command software 7, a power main conversion unit 8, a gate control unit 10 having a gate pulse generation logic circuit 9, a gate drive unit 11, an induction motor 12 to be controlled ing.

The Hall CT1 receives the first phase current Ii1 and outputs the first conversion output Io1. Hall CT2 is the second
It receives the phase current Ii2 as input and outputs the first conversion output Io2. The Hall CT3 receives the third phase current Ii3 and outputs the third conversion output Io3. Outputs Io1, I from Hall CT1, 2, 3
o2 and Io3 are input to the phase current imbalance detection circuit 5 and the effective value calculation circuit 6. In the phase current imbalance detection circuit 5, Io1, I
Calculates the sum of o2 and Io3. The effective value calculation circuit 6 has Io1 and Io.
Calculates and outputs the effective current value IR from o2 and Io3. This is compared with the current pattern Ip determined according to the control pattern in the current command software 7, and the current command ΔI corresponding to the deviation from this is output to the gate pulse generation logic circuit 9
Output to. The gate pulse generation logic circuit 9 causes the power main converter 8 to perform a switching operation commensurate with ΔI.
The pulse PL is output to the gate drive device 11. The gate drive device 11 receives PL and outputs a command PD for driving a power semiconductor which is a switching element of the power main converter.

Main power converter 8 and Hall CTs 1, 2, 3
As long as is operating normally, the relation between the phase currents is Ii1 + Ii2 + Ii3 = 0 from the equilibrium theory. Therefore, Io1 + Io2 even in the conversion output that has been converted by using each phase current as input
+ Io3 = 0 holds. When these Io1, Io2, and Io3 do not satisfy the equilibrium theory, an abnormal situation is determined and the operation of the power conversion unit 8 is stopped.

[0006]

Since the phase current detection system in the conventional inverter control device is configured as described above, the phase current imbalance detection circuit 5 includes the power conversion unit 8 and the Hall CTs 1, 2, and 3. However, the abnormality of the power supply 4 is not detected. Therefore, if an abnormality occurs in the power supply 4,
While the deviation between IR and Ip in the software 7 increases, the control system diverges, which may cause damage to the inverter control device and damage to the controlled object.

An object of the present invention is to detect a phase current Hall CT.
An abnormal power supply is detected by a phase current imbalance detection circuit to provide a highly safe inverter control device.

[0008]

The phase current detection system in the inverter control device of the present invention is a three-phase current detection hole C.
Each T has its own power supply.

[0009]

The phase current detection system in the inverter control device according to the present invention uses the power source of the phase current detection Hall CT individually for each phase, so that when any one phase or two phases become abnormal. , Phase current imbalance is detected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 2 is a main circuit diagram of an inverter control device for an electric vehicle according to an embodiment of the present invention, and FIG. 1 is a block diagram of a phase current detection system in the inverter control device of FIG.

In FIG. 2, 131 is a thyristor for the first phase upper arm, 132 is the first phase lower arm, 133 is the second phase upper arm, 134 is the second phase lower arm, and 135 is the third phase upper arm. Reference numeral 136 is a thyristor of the third phase lower arm. 141 is a freewheel diode of a first phase upper arm, 142 is a first phase lower arm, 143 is a second phase upper arm, 144 is a second phase lower arm, 145 is a third phase upper arm, 146 is a third phase lower arm. This is the freewheel diode of the arm. Reference numeral 15 is a smoothing capacitor, 16 is an overvoltage suppressing resistor, 17 is an overvoltage suppressing thyristor, 18 is a smoothing reactor, 19 is a charging resistor for charging the smoothing capacitor, 2
0 and 22 are circuit breakers, 21 is a high speed circuit breaker, 23 is a pantograph, and 24 is an overhead line.

In FIG. 1, 41 is a Hall CT1 power supply, 42 is a Hall CT2 power supply, and 43 is a Hall CT3 power supply.

Next, the operation will be described. Power supply 41, 4
Since the case where 2 and 43 are normal is similar to the conventional example, the description is omitted, and the case where any one or two of the power supplies 41, 42 and 43 fails will be described. In this case, the inputs Io1, Io2, Io3 to the phase current imbalance detection circuit 5 do not satisfy the balance theory, and the phase current imbalance detection circuit 5 detects the phase current imbalance. Then, the gate pulse generation logic circuit 9
In the above, PL for stopping 131 to 136 is output to the gate drive device 11, and the gate drive device 11 outputs 131 to 13
Output PD for stopping the operation of 6
6 stops operating. Therefore, divergence of the electric vehicle control system can be prevented, and extremely dangerous situations in electric vehicle operation such as damage to the inverter control device and damage to the induction motor to be controlled can be avoided.

[0014]

According to the present invention, the phase current detecting hole C is used.
By making the power source of T separate for each phase, the phase current imbalance detection circuit can detect not only the abnormality of the power main converter and the phase current detection Hall CT, but also the abnormality of the power supply of the phase current detection Hall CT. With this configuration, the divergence of the control system can be suppressed with a simple structure, and a highly safe inverter control device can be obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of a phase current detection system of an inverter control device according to the present invention.

FIG. 2 is a main circuit diagram of an electric vehicle inverter control device according to an embodiment of the present invention.

FIG. 3 is a block diagram of a phase current detection system of an inverter control device according to a conventional example.

[Explanation of symbols]

5 ... Phase current imbalance detection circuit, 7 ... Software, 8 ... Main power converter, 12 ... Induction motor.

Claims (1)

[Claims] 1. A phase current detection system in an inverter control device, comprising an individual power supply for each phase for each phase current detection Hall CT and a phase current imbalance detection circuit.