JP6355130B2 - Motor pseudo load device - Google Patents

Description

The present invention relates to a device for applying a load in a pseudo manner for a torque characteristic test of a rotary motor. In particular, the present invention is intended for a device that uses a DC motor as a generator and applies a pseudo load by the power generation brake effect.

2. Description of the Related Art Conventionally, a rotary motor inspection device is known as a device using a device that applies a load in a pseudo manner. In this type of device, a rotating motor to be measured is provided with a brake along with a torque meter (torque detector) on its power transmission shaft, and torque is generated by the twist generated when the power transmission shaft transmits torque. The necessary load is given by braking effects such as a power generation brake by a generator, a hysteresis brake that causes hysteresis loss, and a powder brake that uses powder as a mechanical resistance.

Patent Document 1 discloses that a DC motor is driven by a rotating motor to be measured and gives a braking effect by performing a power generation operation, and a rotation to be measured using a so-called power generating brake. A motor testing device is disclosed.

Japanese Patent Laid-Open No. 3-212194

A motor pseudo load device using a power generation brake by a DC motor is small and can provide a stable pseudo load at low cost. However, when the operation of the rotating motor to be measured is in a low rotation range, it does not generate electric power as a source of the pseudo load to be applied by the driven DC motor, and as a result, no current flows in the circuit forming the load, which is desired. There was a problem that a pseudo load could not be applied.

The present invention provides a desired pseudo load by allowing a current to flow through a circuit that forms a load even when the operation of the rotary motor to be measured is in a low rotation range, and a stable pseudo load from a low rotation range to a high rotation range. It is an object to provide a motor pseudo-load device capable of providing

The motor pseudo load device of the present invention is
A torque detector coupled to the power transmission part of the rotary motor to be measured;
A DC motor coupled to the torque detector and acting as a power generation brake for the rotary motor for measurement;
A direct current conversion circuit for converting electric power generated when the direct current motor is driven by the rotary motor to be measured into direct current;
A power consuming unit connected in series with the DC converter circuit;
Based on the detected value of the torque detector, the power consumption in the power consumption unit is adjusted, and a load control unit for controlling the pseudo load amount is provided.
A DC variable power source that generates a bias voltage having the same polarity as the output voltage of the DC converter circuit is connected in series with the DC converter circuit and the power consuming unit,
The bias voltage of the DC variable power supply is controlled such that a voltage added to the output voltage of the DC conversion circuit according to a command from the load control unit is equal to or higher than a minimum driving voltage of the power consuming unit. To do.

The load control unit includes a set load input unit, compares the load torque detected by the torque detector with the load torque set in advance by the set load input unit, and determines the power consumption unit according to the difference. It is characterized by giving a command to.

The power consuming unit includes a power transistor, consumes power by flowing a current between the collector and the emitter, and is controlled by a command from the load control unit. And

The minimum driving voltage is a minimum voltage required to flow a current between the collector and emitter of the power transistor in the power consuming unit.

Further, the DC variable power supply is controlled such that the bias voltage is constantly monitored by an output voltage detection unit and fed back to a PWM output control unit to obtain a set voltage value.

According to the motor pseudo load device of the present invention, a voltage is generated by a DC variable power source and a current is supplied to a power consuming unit even in a low rotation range where power generated by a DC motor driven by a rotating motor to be measured is insufficient. It becomes possible to flow. Therefore, stable braking can be realized even for the low rotation operation of the rotary motor for measurement, and a stable pseudo load can be applied from the low rotation range to the high rotation range.

It is a block diagram which shows embodiment of this invention and a motor pseudo load apparatus. It is a block diagram which shows the detail of the direct-current variable power supply in the motor pseudo load apparatus of this invention. It is a flowchart of output voltage control of the direct-current variable power supply in the motor pseudo load apparatus of this invention. It is a flowchart which shows the determination procedure of the control value of the pseudo load in the motor pseudo load apparatus of this invention.

Hereinafter, an embodiment will be described in detail based on FIGS.

FIG. 1 is a block diagram showing an outline of the entire apparatus of the present invention. In FIG. 1, the motor pseudo load device 1 is connected to a power transmission shaft Ms of a rotation motor M to be measured via a drive side coupling 4. On the other hand, in the apparatus of the motor pseudo load device 1, the drive side coupling 4 and one rotating shaft of the torque detector 3 are connected, and the other rotating shaft of the torque detector 3 is connected to the driven side coupling 5. The rotation shaft of the brushless DC motor 2 is connected.

The rotational motor M to be measured is supplied with electric power from the power source P, is controlled at a speed by the drive control unit Dv, and is driven at a predetermined rotational speed. At this time, the brushless DC motor 2 is driven by the rotational motor M to be measured, thereby acting as a generator and generating electric power. Based on the electric power generated by the brushless DC motor 2, the DC conversion circuit 10 generates a DC voltage VM. Further, the DC voltage VM generated by the DC converter circuit 10 is passed through the differential amplifier 36 of the load control unit 30 and the common-mode noise superimposed on the connection line is removed, and then the digital voltage VM is passed through the A / D converter 37. The signal is converted into a signal and input to the CPU 32.

A DC variable power supply 40 is connected in series with the DC conversion circuit 10, and the voltage supplied from the DC power supply 41 is converted into a bias voltage VB by a DC / DC converter 43 formed of an insulating transformer or the like as shown in FIG. Is output. Regarding the setting of the voltage value of the bias voltage VB, a digital signal from the CPU 32 provided in the load control unit 30 is converted into an analog signal by the D / A converter 35 and input to the PWM output control unit 45 as the reference voltage VBref. Is done. Further, the bias voltage VB is constantly monitored by the output voltage detection unit 44 and fed back to the PWM output control unit 45 to perform control to set the voltage value. The reference voltage VBref is also input to a protection circuit 46 that performs overvoltage protection and undervoltage protection, and a limit value for protecting the DC variable power supply 40 is set, and control is performed within the range of the limit value.

As shown in the flowchart of FIG. 3, the processing of the CPU 32 detects the output voltage VM of the DC converter circuit 10 (S1), compares the output voltage VM with the lower limit voltage VL (S2), and sets the lower limit voltage. In the case of VL or more, the bias voltage VB of the DC variable power supply 40 is set to 0V (S3). If the voltage is less than the lower limit voltage VL, a reference voltage VBref is calculated (S4) at which the sum of the output voltage VM of the DC conversion circuit 10 and the bias voltage VB of the DC variable power supply 40 becomes the lower limit voltage VL, and the reference voltage VBref is output. (S5). The lower limit voltage VL indicates the minimum voltage necessary for driving the power consuming unit 20, which will be described in detail later. Among these, the minimum voltage VL is the minimum necessary for flowing the collector current Ic between the collector C and the emitter E of the power transistor 21. The voltage is shown.

On the other hand, the torque detector 3 detects a load torque generated between the rotary motor M to be measured and the brushless DC motor 2 and outputs it to the load control unit 30.

In the load control unit 30, an analog value indicating the detected load torque Tv is converted into a digital value by the A / D converter 31. A set load input unit 33 having an input device such as a key or a switch inputs a pseudo load value (load torque) Tt previously applied to the rotary motor M to be measured, and uses a reference voltage VTref to eliminate the difference as power. Output to the consumption unit 20.

At this time, the CPU 32 reads the detected load torque Tv and the load torque Tt set in advance to be applied as shown in the flowchart of FIG. 4 (S11, S12). Subsequently, a difference dT between the detected load torque Tv and the set load torque Tt is calculated (S13). When the difference dT is larger than zero, the product of the difference dT and the reference adjustment value dV is added to the current reference voltage VTref to obtain a new reference voltage VTref (S14). If the difference dT is smaller than zero, the product of the difference dT and the reference adjustment value dV is subtracted from the current output voltage VTref to obtain a new reference voltage VTref (S15). If the difference dT is zero, the current reference voltage VTref is maintained (S16). Then, the newly determined reference voltage VTref is output (S17). Here, the reference adjustment value dV is a suitable value obtained experimentally.

In the power consumption unit 20, the reference voltage VTref (analog value) is input to the + terminal side of the control amount amplifier 23. Here, since the voltage Vs applied to the current detection resistor R1 is input to the negative input terminal of the controlled variable amplifier 22, the output of the controlled variable amplifier 22 is small when Vs> VTref, and when Vs <VTref. It is controlled to become large.

Vs is determined by the collector current Ic flowing between the collector C and the emitter E of the power transistor 21 and the resistance value Rs of the current detection resistor R1 (Vs = Ic × Rs) in the power consumption unit 20, and further, the power transistor 21 Since the transistor amplifying action is used, the collector current Ic is controlled by the base current Ib flowing between the base B and the emitter E.

The base current Ib is a current that flows between the base B and the emitter E of the power transistor 21 through the power transistor driver 22 through the output of the controlled variable amplifier 23, and is finally controlled to be Vs = VTref. As a result, by adjusting the current amount of the collector current Ic flowing through the power transistor 21, the pseudo load to be applied to the rotary motor M to be measured, that is, the load torque Tv to be detected is changed to a desired pseudo load amount (load torque) Tt. Can be matched.

Therefore, the pseudo load applied to the rotary motor M to be measured includes the output voltage VM of the DC conversion circuit 10 that generates a DC voltage by the power generated by the brushless DC motor 2 acting as a power generation brake, and the above-described DC variable power supply 40. The collector current Ic flows between the collector C and the emitter E of the power transistor 21 and is determined by the magnitude of the current value. Further, the amount of consumption, that is, the magnitude of the collector current Ic, sets the reference voltage VTref to be input to the control amount amplifier 23 according to the difference between the load torque Tv detected by the torque detector 3 and the desired load torque Tt. It becomes controllable.

As described above, in the present embodiment, the pseudo load applied to the rotating motor M to be measured is a constant sum of the voltage generated from the power generated by the power generation of the brushless DC motor 2 and the bias voltage VB of the DC variable power supply 40. By keeping it, control is possible regardless of the rotational speed of the rotary motor M to be measured. That is, even when the rotational motor M to be measured is rotated at a low speed where the power generation by the brushless DC motor 2 becomes insufficient and the output voltage VM of the DC conversion circuit 10 is low, the insufficient voltage is used as the bias voltage of the DC variable power supply 40. A circuit that compensates for VB and allows a sufficient collector current Ic to flow through the power transistor 21 of the power consumption unit 20, and connects the brushless DC motor 2, the DC conversion circuit 10, the DC variable power supply 40, and the power consumption unit 20. The electric current flows above, and the brushless DC motor 2 can generate a power generation brake effect that gives a pseudo load to the rotary motor M to be measured.

In the present embodiment, the DC conversion circuit 10 is configured to compensate for the bias voltage VB of the DC variable power supply 40 when the rotary motor M to be measured rotates at a low speed, and to generate power from the brushless DC motor 2 when the rotary motor M to be measured rotates at a high speed. The output voltage VM allows the collector current Ic to flow through the power transistor 21 of the power consuming unit 20. As a result, the power generation brake of the brushless DC motor 2 is controlled, and a desired pseudo load is applied to the rotary motor M to be measured. It can be stably applied.

In addition, this invention is not limited to the above-mentioned embodiment. It goes without saying that various modifications are possible within the technical scope described in the claims. For example, in the present embodiment, the power consumption unit 20 consumes power in the power transistor 21, but a field effect transistor (FET) can also be used.

DESCRIPTION OF SYMBOLS 1 ... Motor pseudo load apparatus 2 ... Brushless DC motor 3 ... Torque detector 4 ... Driving side coupling 5 ... Driven side coupling 10 ... DC conversion circuit 20 ... Power consumption part 21 ... Power transistor 22 ... Power transistor driver 23 ... Control amount amplifier R1 ... Current detection resistor 30 ... Load control unit 31, 37 ... A / D converter 32 ... CPU (central processing unit) 33, ... Set load input unit 34, 35 ... D / A converter 36 ... Difference Dynamic amplifier 40 ... DC variable power supply 41 ... DC power supply 43 ... DC / DC converter 44 ... Output voltage detection unit 45 ... PWM output control unit 46 ... Protection circuit M ... Rotary motor for measurement Ms ... Power transmission shaft P ... For measurement Power supply for rotary motor Dv ... Drive controller

Claims (5)

A torque detector coupled to the power transmission part of the rotary motor to be measured;
A DC motor coupled to the torque detector and acting as a power generation brake for the rotary motor for measurement;
A direct current conversion circuit for converting electric power generated when the direct current motor is driven by the rotary motor to be measured into direct current;
A power consuming unit connected in series with the DC converter circuit;
In the motor pseudo load device including the load control unit that adjusts the power consumption in the power consumption unit based on the detection value of the torque detector and controls the pseudo load amount,
A DC variable power source that generates a bias voltage having the same polarity as the output voltage of the DC converter circuit is connected in series with the DC converter circuit and the power consuming unit,
The bias voltage of the DC variable power supply is controlled such that a voltage added to the output voltage of the DC conversion circuit according to a command from the load control unit is equal to or higher than a minimum driving voltage of the power consuming unit. Motor pseudo load device. The load control unit includes a set load input unit, compares a load torque detected by the torque detector with a load torque preset by the set load input unit, and instructs the power consumption unit according to the difference. The motor pseudo load device according to claim 1, wherein: The power consuming unit includes a power transistor, consumes power by flowing a current between a collector and an emitter, and a current flowing between the collector and the emitter is controlled by a command from the load control unit. The motor pseudo load device according to claim 1 and 2. 4. The motor pseudo load device according to claim 3, wherein the minimum driving voltage is a minimum voltage required to flow a current between a collector and an emitter of a power transistor in the power consuming unit. 5. The motor according to claim 1, wherein the DC variable power supply is controlled such that the bias voltage is constantly monitored by an output voltage detection unit and fed back to a PWM output control unit to obtain a set voltage value. Pseudo load device.