JPH0679038B2 - 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 4 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 track 3 and the other end are 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 given at a predetermined sampling interval T _S , and electric power having an envelope waveform of 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,
The vehicle runs on the center leg 1A and the track 3 and is accelerated to a predetermined test collision acceleration.

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, the carrier frequency is increased and the resolution is, for example, 10
It is necessary to make it sufficiently high to about μsec, but there is a problem that the carrier frequency cannot be set too high because of dead time.

The present invention has been made to solve the above problems,
It is an object of the present invention to provide a PWM inverter control method capable of improving the waveform of the output waveform by increasing the carrier frequency as compared with the conventional one.

[Means for Solving the Problems]

According to the present invention, the controller switches the dead time to zero except when the zero current command is issued, and at the time of the zero current command, one positive / negative switching element pair of the inverter and the other positive / negative switching element pair are alternately turned on. It is configured to turn on / off.

[Action]

In this invention, since the dead time setting is zero at the time of the drive command and the braking command, the carrier frequency can be increased accordingly, and at the time of the zero current command, the inverter has one positive / negative switching element pair and the other. Since the positive and negative switching element pairs are alternately turned on / off to alternately output currents having different polarities, the current average value can be made zero as instructed, and the current accuracy at the time of zero current instruction can be improved.

〔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 command device, and 26 is an inverter controller, which has a PWM signal generation circuit 27, a delay circuit 28 for setting a dead time, a base drive circuit 29, and a switching circuit 30, and a base drive circuit 29.
Is the base drive signal from the transistors T _{R1 to} T of the inverter 24
Supply to _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, and a gate signal is supplied from a gate controller 31.

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. Further, the command device 25 sends a dead time switching command P _X to the switching circuit 30 to the PWM signal generating circuit 27. The switching circuit 30, which has received the dead time switching command P _X , generates the acceleration command Pg and the braking command P _S as shown in FIG. 2B.
Timing of rising (H level) and extinction timing in synchronization with t ₁ and t ₃
The dead time switching signal X which falls in synchronization with t ₂ and t ₄ (L level) is sent to the delay circuit 28, and the delay circuit 28 outputs the dead time T _D while the dead time switching signal X is at H level. Switch to zero.

Next, the operation of this embodiment will be described with reference to FIGS. Fig. 3 shows the transistor T when the zero current command is issued.
Obtained by the relationship between the _R1 operates and the inverter output current Ia through T _R4, it is taken large time scale than in Figure 2.

In this configuration, when performing the operation confirmation test of the test piece 8, the command device 25 sends the inverter RUN command S (FIG. 2 (c)) for releasing the base lock of the inverter 24 to the inverter controller 26. 24 is placed in a standby state waiting for designation, and a current command having an acceleration command Pg, a zero current command P _O, and a braking command Ps is read at a predetermined sampling interval T _S and sent to the controller 26 of the inverter. Command device 25 is an acceleration command
When Pg is sent, the PWM signal generation circuit 27 compares this with a carrier wave (for example, carrier frequency 6 KHz) to create a PWM signal. The base drive circuit 29 generates a base drive signal based on this PWM signal and supplies it to the bases of the transistors _TR1 and _TR4 . This turns on both transistors T _R1 and T _R4 at the same time.
/ A When turned off, the mover 5 has a drive current (maximum value, for example, 300 amperes) Ia whose envelope waveform is similar to that of the acceleration command Pg Ia
Is supplied, and the mover 5 is rapidly accelerated to reach a predetermined collision acceleration g. During this period, the dead time switching signal X is at the H level, so the dead time setting T _D of the delay circuit 28 is switched to zero.

The output of the command device 25 after the acceleration command Pg is sent becomes a zero command (zero current command) P _O , and the dead time switching signal X changes to the L level. Thus, the inverter 24, as shown in FIG. 4, the process proceeds to the inverter operation and a transistor T _R1, T _R4 pair Nanas transistor T _R2, T _R3 paired is alternately turned ON / OFF, the inverter 24 The output becomes an alternating current as shown in FIG. 3, and the current Ia flowing through the mover 5 becomes zero as an average value. When the time T ₂ has elapsed, the command device 25 outputs the braking command.
Starting to send P _S , the dead time switching signal X changes to the H level again. As a result, the inverter controller 26 sends a base drive signal to the transistors _TR2 and _TR3 , so that both transistors _TR2 and _TR3 start ON / OFF, and the mover 5 has a polarity opposite to that of the drive current Ia. The braking current I _B flows and the mover 5 stops braking.

PWM type inverters usually have a finite dead time T
_{Although D} is always set, in this embodiment, the dead time T _D is set to zero at the time of the acceleration command and the braking command, so that the carrier frequency can be increased accordingly.

Further, in the present embodiment, during the period of T ₂ in which the output of the commander 25 becomes the zero current command P _O , the inverter 24 operates in the normal inverter operation (transistor T _R1 , T _R4 pair and transistor).
Since the pair of T _R2 and T ₃ is turned on / off alternately), the output current average value can be made the zero current according to the command value. Therefore, there is an advantage that vibration of the mover 5 which is lightweight is suppressed and noise is reduced.

〔The invention's effect〕

As described above, according to the present invention, when the acceleration command and the braking command are issued, the dead time is set to zero, so that the carrier frequency and the resolution can be increased, so that a faithful output can be obtained as instructed. At the time of the current command, one and the other of the switching element pairs alternately turn on / off to perform an inverter operation to make the output average value zero, so that the zero current accuracy can be improved.

[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 a dead time switching command in the above embodiment, FIG. 2C is a waveform diagram showing an inverter RUN signal, and FIG. 3 is an operating state of the inverter at the zero current command in the above embodiment. Waveform chart showing the relationship between the output current and the output current. FIG. 4 shows an acceleration tester to which the present invention is applied.
It is a partial cross-sectional side view which shows an example. 1 ... Stator, 2 ... Field coil, 5 ... Mover, 24 ...
… Inverter, 25 …… commander, 26 …… inverter controller, 27 …… PWM signal generation circuit, 28 …… delay circuit, 30 ……
Switching circuit.

Claims (2)

[Claims] 1. A controller for a PWM single-phase inverter that supplies electric power to a movable element having a stator having a field coil and a movable element having an armature coil, and has a positive drive command. , A command device for sending a current command including a zero current command following the command and a braking command of a reverse polarity following the zero current command, and a dead time output of a PWM signal generation circuit for sending a PWM signal in response to the current command. And a controller for sending to the base drive circuit through a delay circuit for setting the dead time, the controller switches the dead time to zero except when the zero current command is issued, and when the zero current command is issued, one of the positive / negative switching elements of the inverter is switched. A PWM type single-phase inverter controller characterized by alternately turning on and off a pair and the other pair of positive and negative switching elements. 2. The PWM system according to claim 1, wherein the command device reads out a current command at a predetermined sampling interval, sends the controller, and gives a dead time switching command for switching the dead time to the controller. Controller for single-phase inverter.