WO2017008452A1

WO2017008452A1 - Method for estimating phase inductance of switched reluctance electric motor that takes iron loss into consideration

Info

Publication number: WO2017008452A1
Application number: PCT/CN2015/099097
Authority: WO
Inventors: 陈昊; 王千龙
Original assignee: 中国矿业大学
Priority date: 2015-07-10
Filing date: 2015-12-28
Publication date: 2017-01-19
Also published as: AU2015402126B2; CN105162366A; AU2015402126A1; CN105162366B

Abstract

A method for estimating phase inductance of a switched reluctance electric motor that takes an iron loss into consideration. The method comprises: injecting a voltage pulse with a voltage value U_S into a phase winding of a switched reluctance electric motor, so that the phase winding generates a current pulse with a current peak value ΔI; using a current sensor to detect the current pulse peak value ΔI; detecting, by a voltage sensor, a total voltage drop value U_ΔT on power switches (S1, S2) in a charging stage and a total voltage drop value U_ΔD on freewheel diodes (D1, D2) in a discharging stage; detecting a rise time value Δt₁ and a fall time value Δt₂ of the current pulse; and based on the parameters above, estimating a phase inductance value L_wo of the switched reluctance electric motor that takes an iron loss into consideration. The estimated phase inductance of the switched reluctance electric motor is small in error and high in precision, and has relatively strong practicality and universality.

Description

Method for estimating phase inductance of switched reluctance motor considering iron loss

Technical field

The invention relates to a method for estimating the phase inductance of a switched reluctance motor taking account of iron loss, and is suitable for a switched reluctance motor system with various phase numbers and using a plurality of power converters.

Background technique

In the traditional injection pulse voltage inductance estimation method of switched reluctance motor, the influence of iron loss is neglected. It is considered that the rise time and fall time of the current generated by the phase winding response are the same, and the rising slope and the falling slope are also the same. However, the iron loss of the switched reluctance motor can not be ignored. In the charging phase, the phase current measured by the current sensor should be the sum of the phase winding current and the iron current; in the discharge phase, the direction of the iron current will be reversed, which will result in The phase current measured by the current sensor shows a rapid decline. The measured phase current of the current sensor should be the difference between the phase winding current and the iron current. Therefore, the iron loss of the switched reluctance motor leads to the large phase inductance error of the conventional injection pulse voltage current peak method and current slope method. The accuracy is not high.

Summary of the invention

The object of the present invention is to overcome the deficiencies in the prior art, and to provide a method for estimating the phase inductance of a switched reluctance motor with simple method, small error, high precision and iron loss.

The method for estimating the phase inductance of a switched reluctance motor considering iron loss according to the present invention, injecting a voltage pulse into a phase winding of a switched reluctance motor, causing a phase pulse of the switched reluctance motor to generate a current pulse, and detecting a phase winding response by a current sensor The current pulse peak value only needs to detect the current pulse rise time value and the fall time value; the voltage sensor is used to detect the injection voltage pulse voltage value, and the injection voltage pulse is injected into the switching reluctance motor phase winding to charge the total voltage drop value on the power switch and The total voltage drop value of the discharge phase on the freewheeling diode can be used to calculate the phase inductance value of the switched reluctance motor taking into account the iron loss. The specific steps are as follows:

(1) injecting a voltage pulse with a voltage value of U _{S to} the phase winding of the switched reluctance motor, so that the phase winding of the switched reluctance motor responds to generate a current pulse having a peak value of current pulse ΔI;

(2) detecting the peak value of the current pulse generated by the phase winding of the switched reluctance motor by the current sensor as ΔI, detecting the rising time value Δt _{1 of the} current pulse peak ΔI and the falling time value Δt _{2 of the} current pulse peak ΔI;

(3) Using a voltage sensor to detect the voltage value U _{S of the} injected voltage pulse, and using the voltage sensor to detect the total voltage drop value U _{ΔT of the} injected voltage pulse injected into the charging phase of the switched reluctance motor phase winding on the power switch, and detecting the discharge through the voltage sensor The total pressure drop value U _{ΔD of the} phase on the freewheeling diode,

(4) by the following formula:

The phase inductance value L _w of the switched reluctance motor taking into account the iron loss can be calculated.

Advantageous Effects: The present invention injects a voltage pulse into a phase winding of a switched reluctance motor, and uses a current sensor to detect a peak value of a current pulse generated by a phase winding response, and only needs to detect a current pulse rise time value and a fall time value, and the voltage sensor only needs to detect the injection. The voltage pulse voltage value, the injection voltage pulse injected into the phase winding of the switched reluctance motor, the total voltage drop value on the power switch and the total voltage drop value on the freewheeling diode during the discharge phase can be calculated to take into account the iron loss. The phase inductance value of the switched reluctance motor is small, and the real-time performance is good. The estimated phase reluctance motor has small inductance error, high precision, and is not affected by the loss of motor iron. It has strong practicability and versatility, and has a wide range of Application prospects.

DRAWINGS

1 is an equivalent circuit of a phase winding of a switched reluctance motor according to the present invention;

2 is a schematic structural view of an injection voltage pulse double-switching power circuit of the present invention;

3 is a schematic diagram of current pulses generated by the response of the injection voltage pulse phase winding of the present invention;

4 is a schematic view showing the structure of an injection voltage pulse double winding power circuit of the present invention.

detailed description

The embodiments of the present invention are further described below with reference to the accompanying drawings:

The method for estimating the phase inductance of a switched reluctance motor considering iron loss according to the present invention has the following specific steps:

(4) by the following formula:

Embodiment 1 Taking a switched reluctance motor system using a two-switch power converter of each phase as an example,

As shown in FIG. 1 , an equivalent circuit of a phase reluctance motor of a switched reluctance motor, which includes a loss of iron, includes a phase reluctance motor phase inductance L _w , a ferroelectric equivalent resistance R _iron connected in parallel across the phase inductance L _w , and a phase The winding resistance R _cop , i _tot is the phase current that the current sensor can detect, i _w is the actual current of the phase winding, and i _iron is the equivalent iron current.

As shown in FIG. 2, a voltage pulse with a voltage value of U _S is injected into the phase winding of the switched reluctance motor by a two-switch power converter per phase, and the voltage value of the injected voltage pulse U _{S is} detected by a voltage sensor, and the voltage applied to the phase winding is applied. The value is U _t ; during the charging phase, the power switches S ₁ and S _{2 are} closed, as shown in Figure 3, the phase winding responds to generate a current pulse with a current peak value of ΔI, and the phase current i _tot measured by the current sensor should be the actual phase winding. The sum of the current i _w and the equivalent iron current i _iron , the total voltage drop value U _ΔT of the sum of the total voltage drops on the power switches S ₁ and S ₂ is detected by the voltage sensor, and the rise time value of the current pulse peak ΔI is detected. Δt ₁ ; During the discharge phase, the power switches S ₁ and S _{2 are} disconnected, the current pulse is attenuated by the freewheeling diodes D ₁ and D ₂ , and the direction of the iron current is reversed, resulting in the phase current measured by the current sensor. _Tot shows a trend of rapid decline, as shown in Figure 3, the phase current i _tot measured by the current sensor should be the difference between the actual current i _w of the phase winding and the equivalent iron current i _iron . The freewheeling diode D _{1 is} detected by the voltage sensor. And on D ₂ The total pressure drop value U _ΔD of the sum of the total pressure drops, the falling time value Δt _{2 of the} detected current pulse peak ΔI;

Embodiment 2, taking a switched reluctance motor system using a two-winding power converter per phase as an example,

As shown in Fig. 1, the equivalent circuit of the phase winding of the switched reluctance motor considering the iron loss includes the phase reluctance motor phase inductance L _w and the iron loss equivalent resistance R _iron connected in parallel across the phase inductor L _w and the phase winding The resistance R _cop , i _tot is the phase current that the current sensor can detect, i _w is the actual current of the phase winding, and i _iron is the equivalent iron current.

As shown in FIG. 4, a voltage pulse with a voltage value of U _S is injected into the phase winding of the switched reluctance motor by a two-winding power converter per phase, and the voltage value of the injection voltage pulse U _{S is} detected by a voltage sensor, and the voltage applied to the phase winding is applied. The value is U _t ; the charging phase, the power switch S is closed, as shown in Figure 3, the phase winding responds to generate a current pulse with a current peak value of ΔI, and the phase current i _tot measured by the current sensor should be the actual current i _w of the phase winding and The sum of the equivalent iron currents i _iron , the total voltage drop value U _ΔT on the power switch S is detected by the voltage sensor, the rise time value Δt _{1 of the} current pulse peak ΔI is detected, and the power switch S is disconnected, the current pulse is discharged during the discharge phase. Through the freewheeling of the freewheeling diode VD path, the direction of the iron current is reversed, resulting in a rapid decline of the phase current i _tot measured by the current sensor. As shown in Figure 3, the measured phase current i _{tot of the} current sensor should be actual current to the phase winding equivalent iron and i _w i _iron consumption current of the _difference, U ΔD, ΔI detected current pulse peak value of the total pressure drop is lowered by the voltage sensor detects a freewheeling diode D Intermediate value Δt _2; calculated by the formula:

Claims

A method for estimating the phase inductance of a switched reluctance motor considering iron loss, characterized in that: a voltage pulse is injected into a phase winding of a switched reluctance motor, so that a phase pulse of the switched reluctance motor generates a current pulse, and the phase winding is detected by the current sensor. In response to the generated current pulse peak, only the current pulse rise time value and the fall time value are detected; the voltage sensor is used to detect the injected voltage pulse voltage value, and the injected voltage pulse is injected into the switched reluctance motor phase winding to charge the total voltage on the power switch. The value of the total voltage drop on the freewheeling diode during the derating and discharging phases can be used to calculate the phase inductance of the switched reluctance motor taking into account the iron loss. The specific steps are as follows:

(1) injecting a voltage pulse with a voltage value of U S to the phase winding of the switched reluctance motor, so that the phase winding of the switched reluctance motor responds to generate a current pulse having a peak value of current pulse ΔI;

(2) detecting the peak value of the current pulse generated by the phase winding of the switched reluctance motor by the current sensor as ΔI, detecting the rising time value Δt 1 of the current pulse peak ΔI and the falling time value Δt 2 of the current pulse peak ΔI;

(3) Using a voltage sensor to detect the voltage value U S of the injected voltage pulse, and using the voltage sensor to detect the total voltage drop value U ΔT of the injected voltage pulse injected into the charging phase of the switched reluctance motor phase winding on the power switch, and detecting the discharge through the voltage sensor The total pressure drop value U ΔD of the phase on the freewheeling diode,

(4) by the following formula:

The phase inductance value L w of the switched reluctance motor taking into account the iron loss can be calculated.