JPH0232401A - Control device for inverter - Google Patents

Abstract

PURPOSE:To execute the continuous clocking action by executing the feeding of a clocking element from an auxiliary power source with a feeding switching circuit when the stop of a direct current power to an inverter control device is detected by a feeding stopping detecting circuit. CONSTITUTION:When a switch 2 is opened and the feeding of a three-phase power source 1 is stopped, a direct current/direct current converter 11 drops up to the set voltage. As the result, a feeding stopping circuit 14 detects the stop of the converter 11. By the detecting signal, a feeding switching circuit 15 is operated, the feeding from the converter 11 to a clocking element 16 is switched from an auxiliary power source 12 and the clocking element 16 and the timing element 16 is always operated. By such a constitution, since the continuous clocking action can be executed, the operation rate of the inverter operation can be calculated and the exchanging time of a capacitor 4 is found.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an inverter control device incorporating a timing element.

[Conventional technology]

Conventionally, as an inverter control device of this type, one shown in FIG. 3, for example, is known. FIG. 3 is a basic configuration block diagram of a conventional inverter control device. In the figure, 1 is a three-phase power supply, and this three-phase power supply 1 includes a switch 2
A rectifier 3 is connected through the rectifier 3 and converts the AC power of the three-phase power supply 1 into DC power. The DC power output from the rectifier 3 has ripples smoothed out by a capacitor 4. Reference numeral 5 denotes an inverter that converts DC power into an arbitrary voltage and frequency, and a motor 6, which is a load, is connected to the inverter 5. 7 is a microprocessor that commands and controls the output voltage and frequency of the inverter 5; 8 is an amplifier circuit that amplifies the control signal output from the microprocessor 7 and inputs it to the inverter 5; 9 is not supplied with power; (However, it is a memory element (e.g., E" ROM) that can retain the memory contents, erase the memory contents electrically, and write new information. 10 indicates the operating frequency etc. controlled by the microprocessor 7. 11 is a controller that displays values such as the operating frequency at the same time as inputting the value. 11 converts the DC power across the capacitor 4 to a low voltage and supplies it to the microprocessor 7, memory element 9, and controller 10. This is a DC/DC converter that supplies this low voltage. Next, the operation will be explained. When the circuit is closed by the switch 2, the AC power from the three-phase power supply 1 starts to supply power to the rectifier 3, and at the same time, the capacitor 4
Charging will also start. As a result, from the DC/DC converter 11, the microprocessor 7, the memory element 9,
Power supply to each controller 10 is started, and each starts operating. Therefore, from the controller 10, the rotation direction of the motor 6,
Set the frequency. As a result, the microprocessor 7 calculates the pattern signal input to the inverter 5 and commands and controls the output voltage and frequency. The signal is then amplified by the amplifier circuit 8, and the pattern signal operates the inverter 5 to rotate the motor 6. Conventional inverter control devices are configured as described above, so a microprocessor is used to control the inverter. When the circuit is opened with a switch while the timer is running,
When the three-phase power supply stops supplying AC power and DC power stops, the DC/DC converter cannot supply power to the microprocessor, memory element, and controller.
Naturally, when the microprocessor stops operating, the time it was calculating is also lost, and when it starts operating again, it is initialized, making it impossible to perform continuous timekeeping operations. was there. This invention was made to solve these problems, and it provides an inverter that can perform continuous timekeeping even when the DC power supply is stopped and the microprocessor stops operating. The purpose is to obtain a control device.

[Means to solve problems] The inverter control device according to the present invention includes a rechargeable auxiliary power source and a timing element that performs a timing operation, detects that the DC power supplied to the inverter control device has stopped, and issues a power supply stop signal. It is equipped with a power supply stop detection circuit that outputs a power supply stop detection circuit, and a power supply switching circuit that switches the power supply to the time measuring element to be supplied from the auxiliary power source when receiving the power supply stop signal output from the power supply stop detection circuit. [Effect]

In this invention, when the power supply stop detection circuit detects that the DC power supplied to the control device of the inverter has stopped, the power supply switching circuit switches the power supply to the timing element to be supplied from the auxiliary power source.

【Example】

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a schematic block diagram showing an embodiment of an inverter control device according to the present invention, and FIG. 2 is a circuit diagram of a power supply switching circuit of the embodiment. In the figure, the same reference numerals as those in FIG. 3 of the conventional example indicate the same parts, and explanations of their configurations and operations will be omitted as appropriate. Reference numeral 12 denotes an auxiliary power source, and a diode 13 for preventing backflow is connected in series to the auxiliary power source 12. Reference numeral 14 denotes a power supply stop detection circuit, and as shown in FIG. When the voltage drops to the set voltage,
It detects that the DC/DC converter 11 has stopped and outputs a power supply stop signal A. The power supply stop signal A output from the power supply stop detection circuit 14 is
The signal is input to the base of a transistor 15a of a power supply switching circuit 15 that switches power supply between the DC/DC converter 11 and the auxiliary power supply 12. With this power supply switching circuit 15,
The switched power supply is adapted to supply power to a timekeeping element 16 that includes a reference oscillator and performs a timekeeping operation. Next, the operation will be explained. When the circuit is closed by the switch 2 and AC power from the three-phase power supply 1 starts to be supplied to the rectifier 3, the conventional operation is performed. Conversely, when the switch 2 is opened and the supply of AC power from the three-phase power source 1 is stopped, the output voltage of the DC/DC converter 11 drops to the set voltage. As a result, the power supply stop detection circuit 14 detects that the DC/DC converter 11 has stopped, and outputs a power supply stop signal. The power supply switching circuit 15 is activated by the power supply stop signal output from the power supply stop detection circuit 14, and the DC/DC converter 11
The state in which power is supplied to the timekeeping element 16 is switched to the power supply to the timekeeping element 16 by the auxiliary power supply 12, and the timekeeping element 16 is constantly operated. Further, the explanation will be made with reference to a specific circuit diagram shown in FIG. When the emitter voltage of the transistor 15a is high (DC/
When power is being supplied by the DC converter 11), the potential becomes higher than the potential of the Zener diode 14d connected to the base, a base current flows, and the transistor 15a becomes conductive. Then, the DC/DC converter 11 supplies power to the timing element 16 . Conversely, when the DC/DC converter 11 stops and the output voltage decreases, the potential of the Zener diode 14d becomes low and the base current stops flowing, turning the transistor 15a into a cutoff state, and the auxiliary power supply 12 supplies the clock element 16 with It will start supplying power. Also, at this time, diode 1
The voltage of 4a also decreases, and the signal causes the clock element 16 to
Switch to auxiliary power mode. Therefore, when the switch 2 is turned off, only the time measuring element 16 continues to operate by being supplied with power from the auxiliary power source 12. In the embodiment of the present invention configured as described above, even when the switch 2 is turned off, only the timekeeping element 16 continues to operate by being supplied with power from the auxiliary power source 12, so that continuous timekeeping operation can be performed. As a result, the operating rate of the inverter operation can be calculated from the time during which the inverter is operating and the time during which the inverter operation is stopped. Furthermore, when the lifespan of the capacitor 4 is given as a predetermined value, the replacement time can be calculated based on the operating rate of the inverter operation. Further, when an abnormality occurs during operation of the inverter, the time can be read, stored in the memory element 9, and displayed later through a display device or the like.

【Effect of the invention】

As described above, according to the present invention, a rechargeable auxiliary power source and a timing element that performs a timing operation are provided, and a power supply stop signal is sent by detecting that the DC power supplied to the inverter control device has stopped. The inverter is equipped with a power supply stop detection circuit that outputs a power supply stop detection circuit, and a power supply switching circuit that switches the power supply of the timing element to the auxiliary power supply when receiving the power supply stop signal output from the power supply stop detection circuit. When the DC power supplied to the control device stops, by starting the power supply to the timing element from the auxiliary power supply, even if the DC power supply stops and the microprocessor stops operating, continuous power can be maintained. This has the excellent effect of allowing accurate timekeeping operations to be performed.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing an embodiment of an inverter control device according to the present invention, FIG. 2 is a circuit diagram of a power supply switching circuit of the embodiment, and FIG. 3 is a basic configuration of a conventional inverter control device. It is a block diagram. In the figure, 5 is an inverter, 6 is a motor, 12 is an auxiliary power supply, 14 is a power supply stop detection circuit, 15 is a power supply switching circuit, 1
6 is a timing element. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] In an inverter control device that is equipped with an inverter that converts DC power into any voltage and frequency, and that operates a motor as an inverter, it has a built-in rechargeable auxiliary power source and a reference oscillator to perform timekeeping operations. a power supply stop detection circuit that detects that the DC power has dropped to a set voltage and that the power supply has stopped to the inverter control device and outputs a power supply stop signal; An inverter control device comprising: a power supply switching circuit that switches the power supply to the time measuring element to be supplied from the auxiliary power source when receiving a power supply stop signal.