JPH0679037B2 - PWM single-phase inverter controller - Google Patents

Description

The present invention relates to a control device for a PWM single-phase inverter used for power amplification.

[Conventional technology]

One of the acceleration testers for carrying out the operation confirmation test of the acceleration sensor for detecting the operation timing of the airbag in the airbag unit mounted in an automobile or the like and used for saving lives in the event of a vehicle collision. 2. Description of the Related Art There is an electromagnetic solenoid type in which a mover side having a test stand on which is mounted is rapidly driven by an electromagnetic force to obtain a desired collision acceleration for a test.

Figure 5 shows this electromagnetic solenoid type tester.
In the figure, reference numeral 1 is an E-shaped stator (field yoke), which is made of a magnetic material and to which a field coil (field coil) 2 is attached. A track 3 extends horizontally from a central leg 1A extending through the field coil 2, and the other end of the track 3 is supported by a receiving portion 4 located at a predetermined distance from the central leg 1A. Reference numeral 5 denotes a cylindrical hollow air-core mover (aluminum armature coil) having openings at both ends, and free wheels are provided on the upper and lower inner circumferences on one end side.
6U and 6D are attached, and a test stand 7 for mounting a test piece (acceleration sensor) 8 and sensors extends from the other end, and a free wheel 6C is attached to the lower side of the test stand 7. It is worn.
The mover 5 is fitted onto the central leg 1A by engaging the free wheels 6U and 6D with the upper and lower surfaces of the central leg 1A, and the free wheel 6C of the test stand 7 engages with the upper surface of the track 3. Reference numeral 9 is a power supply device that supplies electric power to the coil of the mover 5, 10 and 11 are power supply lines, and 12 is a field power supply device.

In this configuration, when the test piece 8 is tested, a field current is passed through the field coil 2 and the power supply 9
2A, an acceleration command Pg as shown in FIG. 2A is applied to supply electric power to the movable element 5 through the power supply line 10 so that the envelope waveform becomes the waveform shown in FIG. As a result, a thrust force acting in the direction of the solid arrow in the figure acts on the mover 5. Upon receiving this thrust, the mover 5 is rapidly accelerated, travels on the center leg 1A and the track 3, and is accelerated to a predetermined test collision acceleration. In 8, the operation is confirmed. The movable element 5 accelerated as described above gives a braking command P _S after a predetermined time T ₂ has passed after reaching a predetermined test acceleration, and stops by supplying a braking current of reverse polarity.

[Problems to be Solved by the Invention]

When the control of the mover is performed by using a PWM inverter, in order to make the inverter output faithfully follow the acceleration command Pg and the braking command P _S , the carrier frequency (switching frequency) is increased and the resolution is It is necessary to make it sufficiently high, but since the mover 5 is an air-core lightweight object consisting of an armature coil, when the switching frequency becomes high, electromagnetic noise (beats) in the audible frequency band is generated depending on the carrier frequency. There was a problem that it made me feel uncomfortable.

The present invention has been made to solve the above problems,
An object of the present invention is to provide a control device for a PWM inverter, which can shorten the generation period of electromagnetic noise and can reduce discomfort as compared with the conventional case.

[Means for Solving the Problems]

In order to achieve the above object, the present invention is configured to suspend the switching operation of the inverter when the zero current command of the current command is issued.

[Action]

According to the present invention, since the switching operation of the inverter is stopped when the zero current command is issued, no electromagnetic noise is generated during this period.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 21 is a single-phase AC power supply, 22 is a rectifier, and 23
Is an electrolytic capacitor, 24 is an inverter functioning as a power amplifier, and four power transistors _TR1 , _TR2 ,
Bridged connection of T _R3 and T _R4 , and its AC output terminal A
A mover (armature coil) 5 is inserted between the position B and the position B. D is a flywheel diede.

Reference numeral 25 is a commander, and 26 is an inverter controller, which has a PWM signal generation circuit 27 and a base drive circuit 28. The base drive circuit 28 sends a base drive signal to the transistor T of the inverter 24.
Supply to _{R1 to} T _R4 . 27A is a carrier wave generation circuit and 27B is a comparison circuit. The field power supply device 12 is a rectifier device in which a controllable rectifying element Sh is bridge-connected and the phase is controlled.
A gate signal is supplied from the gate controller 29.

The commander 25 is composed of a microcomputer CPU, is given a test acceleration g and other parameters through an input device (not shown), and stores it in a memory (not shown). The harbor sine waveform as shown in FIG. Acceleration command (driving command) with time width that has, for example, time width T ₁ = 10 to 20 ms
Pg and, for example, a rectangular wave braking command P _S having a time width T ₃ is calculated. The command device 25 also sends an inverter RUN command S for releasing the base lock of the inverter 24 to the inverter controller 26.
Send to. This inverter RUN command S is shown in Fig. 2 (b).
As shown in, the timing of generation of acceleration command Pg and braking command P _S
Occurs in synchronization with t ₁ and t ₃ (H level), and disappearance timing
It is a signal (L level) that disappears in synchronization with t ₂ and t ₄ .

Next, the operation of this embodiment will be described with reference to FIGS. Note that FIG. 3 shows the relationship between the operation of the inverter and the output current when a braking command is issued, and FIG. 4 shows the relationship between the operation of the inverter and the output current when a conventional zero current command is issued. The time scale is larger than in the case of the figure. In this configuration, when performing the operation confirmation test of the test piece 8, the command device 25 sends the inverter RUN command S to the inverter controller 26, and at the same time, outputs the current command having the acceleration command Pg and the braking command P _S at the predetermined sampling interval T _The operation of reading out for each _S and sending it to the inverter controller 26 is started. When the command device 25 sends the acceleration command Pg, the PWM signal generation circuit 27 compares it with a carrier wave (for example, carrier frequency 6 KHz) to create a PWM signal. The base drive circuit 28 uses this PWM
Generate a base drive signal based on the signal
Supply to the base of _R1 and T _R4 . As a result, both transistors T _R1 and T _R4 are turned ON / OFF at the same time, and the movable element 5 is supplied with a drive current (maximum value, for example, 300 amperes) Ia whose envelope waveform is similar to the envelope waveform of the acceleration command Pg. The child 5 is rapidly accelerated to reach a predetermined collision acceleration g.

When the command device 25 finishes sending the acceleration command Pg, it sends the zero current command, but since the inverter RUN signal S disappears at the same time, the controller 26 suspends the sending of the base drive signal.

At the end of the zero current command period T ₂ , the command device 25 turns the inverter RU
It sends the N signals S, at the same time, since the start sends a braking command P _S, the inverter controller 26 sends a base drive signal to the transistor T _R2 and T _R3, both transistors T _R2 and T _R3 is ON / O
Start FF operation. Thus, the movable element 5, as shown in Figure 3, the braking current I _S of opposite polarity flows through the drive current Ia, the movable element 5 is made to stop braking.

As shown in FIG. 2 (C), the conventional inverter RUN signal (denoted by Sp) is generated even at the time of the zero current command, and the transistors T _R1 and T _R4 of the inverter 24 are as shown in FIG. In addition, since the switching control was performed so that the average value of the inverter output current was substantially 0, the electromagnetic noise was generated. However, in the present embodiment, at the time of the zero current command,
Since the inverter 24 is stopped, the electromagnetic noise is not generated, and the electromagnetic noise is generated only when the acceleration command and the braking command are issued.

〔The invention's effect〕

As described above, the present invention suspends the switching operation of the inverter during the zero current command period of the current command including the drive command, the zero current command and the braking command.
Conventionally, the electromagnetic noise generated during the entire period of the current command will be generated only during the drive command period and the braking command period.
To that extent, discomfort can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIG. 2 (a).
Is a waveform diagram showing the output of the commander in the above embodiment,
FIG. 2B is a waveform diagram showing an inverter RUN command in the above embodiment, FIG. 2C is a wave form diagram showing a conventional inverter RUN command, and FIG. 3 is an operation of the inverter at the time of a braking command in the embodiment. 4 is a waveform time chart showing the relationship between the state and the output current, FIG. 4 is a waveform time chart showing the relationship between the operating state of the conventional inverter and the output current at the time of zero current command, and FIG. 5 is the acceleration tester to which the present invention is applied. It is a partial cross-sectional side view showing an example of FIG. 1 ... Stator, 2 ... Field coil, 5 ... Mover, 24 ...
… Inverter, 25 …… commander, 26 …… inverter controller, 27 …… PWM signal generation circuit, 28 …… base drive circuit.

Claims (1)

[Claims] 1. A controller of a PWM single-phase inverter for supplying electric power to a movable element of an apparatus having an air-core movable element composed of a stator equipped with a field coil and an armature coil, wherein the controller has a positive polarity. Control including a drive command, a zero current command following the command, and a command command for sending a current command including a braking command of a reverse polarity following the zero current command, and a PWM signal generation circuit for receiving the current command and sending a PWM signal A controller for a PWM inverter, wherein the commander reads out a current command at a predetermined sampling interval and sends it to a controller, and when the zero current command is issued, the switching operation of the inverter is suspended.