KR20090029315A - Operating a three phase device using single phase power - Google Patents

Abstract

A powering arrangement (32, 34) for a device (30, 22) that normally operates on three phase power has the capability of operating based upon single phase power. One disclosed technique includes estimating a direct component based upon a measured voltage across the leads coupled with the single phase power supply. The quadrature component is estimated based upon a numerical derivative of the direct component. The direct component is also provided to a current regulator in a feed forward control manner, which minimizes error.

Description

How to operate a three-phase device using single-phase power {OPERATING A THREE PHASE DEVICE USING SINGLE PHASE POWER}

The present invention generally relates to a power control system. In particular, the present invention relates to providing single phase power to devices that normally operate with three phase power.

Electric motors are well known and widely used. Electric motors come in a variety of sizes and types. One example of the use of an electric motor is shown in an elevator machine that moves a drive sheave for raising or lowering the elevator car, for example, via a hoistway.

Recently, regenerative drive machines have been introduced into elevator systems. The regenerative drive machine includes an electric motor that receives power from the power source to move the car and counterweight through the hoistway in the first direction and generates power back to the power source when attempting to move the car and counterweight in the opposite direction. do. The regenerative drive utilizes the ability of the electric motor to act as a generator when the weight of the car and counterweight causes a certain movement while the drive machine allows the drive sheave to move properly.

This regenerative drive machine operates on three-phase power input. Three-phase power input may not be possible. For example, while an initial elevator system is being installed, three phase power sources are generally not available for building sites. While the elevator system is installed, only single phase power can be used. In many cases, it is required to be able to move the elevator at least in limited mode during installation. The problem is that without three-phase power, the regenerative three-phase drive machine cannot be operated and thus cannot be used in the installation of the elevator.

If three-phase power is not available, it is necessary to use regenerative three-phase drive machines even during elevator installation. Even when three-phase power is unavailable, there are other cases where a three-phase device is useful. The present invention addresses the need to be able to provide single phase power for operating a three phase device.

One exemplary disclosed converter device for providing power to a three phase device using single phase input power uses an estimated direct component and an estimated quadrature component based on the single phase input power. A phase locked loop (PLL) unit is included.

In one example, the direct component is estimated based on the measured voltage of the single phase input power. Orthogonal components are estimated based on the numerical derivative of the estimated direct components. In one example, the numerical derivative is scaled based on the frequency of the input power.

As an example, the current regulator uses an estimated direct component of the single phase input power as a feed forward input to minimize errors when supplying current to the three phase device.

The exemplary arrangement disclosed facilitates the use of a regenerative three phase device even if only single phase power is available to operate the device.

Various features and advantages of the invention will be apparent to those skilled in the art from the following detailed description of the present preferred embodiment. The drawings with the detailed description can be briefly described as follows.

1 is a schematic diagram illustrating selected portions of an elevator system 20. The drive machine 22 includes, for example, an electric motor that propels the roping 24 to enable a predetermined movement of the elevator car 26 and the counterweight 28 via a hoistway in a known manner. In this example, the drive machine 22 comprises a regenerative three phase machine such that the electric motor can be used to provide power in generator mode according to known motor operating principles. In this example, the drive machine 22 generally includes an electric motor that operates based on three phase electrical power.

The controller 30 provides a control signal for operating the motor of the drive machine 22. The controller 30 is powered from a power source 32 which is ultimately a three phase power source. Converter interface 34 ensures that there is an appropriate phase provided to controller 30, for example, to obtain the desired drive machine operation.

In some cases, such as in an elevator system installation process, the power source 32 may not be available as a three phase power source. In some cases, single phase power is available during construction work and thus during elevator system installation. The converter interface 34 of this example can be used regardless of whether the power supply 32 is a single phase power supply or a three phase power supply. The converter interface 34 operates by adjusting the difference between the single-phase power supply and the three-phase power supply so that the controller 30 and the driving machine 22 can operate in at least a limited mode while the elevator system is installed. One advantage of the disclosed example is that converter interface 34 does not require separate converters or separate hardware components for operation responsive to single phase power. Instead, converter interface 34 adjusts machine operation according to whether the power supply is three-phase or single-phase.

2 is a schematic diagram illustrating a selected portion of converter interface 34 as an example. The filter part 36 operates in a generally known manner. The current regulator portion 38 includes inductive and resistive elements as is known for regulating the current provided to the phase locked loop (PLL) portion 40. The bus voltage regulator 42 provides a final current signal to the regulator 30 for operating the drive machine 22.

When the power supply 32 provides three phase power (ie, R phase, S phase, T phase), the example of the converter interface 34 of FIG. 2 generally works. The example of FIG. 2 is shown in conditions that are well suited for response to single phase power. The T input 44, ie the IGBT H-bridge T input, is disconnected and receives no more power. This can be done, for example, by a mechanical switch (not shown) in the converter interface 34. Thus, when the technician attempts to connect the single phase power for operating the regulator 30 and the drive machine 22, a suitable switch can be operated so that the T input 44 of the IGBT leg is not connected with the power source 32. have. The outputs from the PLL portion 40 and the bus voltage regulator 42 operate only based on the R input 46 and S input 48 of the IGBT leg. The control arrangement providing the switching function for the IGBT H-bridges at the R and S inputs 46 and 48 allows operating the drive machine 22 in response to single phase power. In this example, the R input 46 is connected to one of the single phase power leads while the S input 48 is connected to the other lead.

3 is a schematic diagram illustrating an example of a control arrangement that provides a switching function for operation using single phase power. Reference voltage 50 is provided to summer 52. In one example, the reference voltage is 750 volts. The reference voltage will depend in part on the available power source. The output of the bus voltage regulator portion 42 is provided at 54 for providing a current to the controller 30. Output 54 is provided to the negative input of summer 52.

The output of summer 52 is provided to proportional integral controller 56. The function of the proportional integral regulator 56 is to indicate how much current is needed to eliminate the error between a given current level and the output current level 54 ultimately provided to the controller 30.

The output of proportional integral regulator 56 is provided to multiplier 58. The other input to multiplier 58 comes from PLL 40. In this example, PLL 40 is used to estimate the quadrature component of the phase of the input power. Since single phase power is provided and the PLL generally operates based on three phase power, it is necessary to effectively convert single phase power into a three phase model for operational purposes.

In this example, the PLL uses an estimate of the direct and quadrature phases of the input power. As an example, the voltage across inputs 46 and 48 is sensed using conventional techniques. The measured voltage is used as an estimate of the direct component phase.

In this example, the orthogonal component phase is estimated by taking the numerical derivative of the direct component phase. As an example, the scale of the orthogonal component is applied after the numerical derivative of the direct component phase of the line voltage.

이다.In one example, V _d = V _ac sin (θ), thus d / dt V _d = V _ac ω _line cos (θ). In general, the line frequency is unknown but will be 50 or 60 hertz. Estimating the orthogonal component of the phase in this example involves scaling a numerical derivative based on the estimated line frequency, which is performed by the PLL section 40. As an example, a gain of 1 / ω _line = 1 / (2π60) is applied when the frequency is greater than 55 Hz. If the frequency is below 55 Hz, a gain of 1 / ω _line = 1 / (2π50) is used. The estimated quadrature phase (ie, q-axis voltage) for the PLL section 40 is

to be.

Once the estimated orthogonal component is obtained, the PLL section 40 acts as a three phase equivalent.

3, the output from the PLL section 40 to the multiplier 58 is a sinusoidal reference output from the PLL that is in phase with the line voltage and is coupled with the output of the proportional integral regulator 56 so as to combine the current regulator section 38 with the output section. Provide a current reference for

The input to the current regulator portion 38 is provided to the positive input of the summer 60. The output of summer 60 is provided to proportional regulator 62. The output of proportional regulator 62 is provided to summer 64 coupled with feed forward input 66. In this example, feed forward input 66 is represented as VR_VS. This voltage is equal to the sensed line voltage between the R input and the S inputs 46 and 48. The feed forward input 66 provides a current regulator 38 that can minimize current regulation errors. As an example, the feed forward input 66 is identical to the direct component of the input to the PLL 40.

The output of summer 64 is processed in a generally known manner by current regulator element 68, represented by line current I_line.

Since the single phase current regulator operates differently from the synchronous current regulator in that the disturbance of the single phase current regulator is not constant, the proportional regulator 62 is provided in the example of FIG. 3 instead of the proportional integral regulator. As is known, the proportional integral regulator very well rejects constant disturbance, but the disturbance to the single phase current regulator is not constant. In this example, a strategic combination of the feed forward input 66 and the proportional regulator is shown which acts as a disturbance and corresponds to, for example, the sinusoidal line voltage associated with the R and S inputs 46 and 48. If the feed forward input 66 cancels the voltage disturbance, the current regulator 38 may be designed as shown in FIG.

As an example, the bandwidth of the proportional regulator 62 is based on the proportional integral regulator structure. As shown in Fig. 4, the regulator 62 'is designed in the form of a function block comprising a gain K _p . Given a requirement that requires a certain phase margin (Ø _m = 60 °), the proportional gain can be solved through K _p = Lω _c , K _i = ω _c R, where the predetermined bandwidth ω _c is It can be determined from the delay T _d , and the predetermined phase margin is limited using the equation ω _c = (π / 2 − Ø _m ) / T _d . The delay T _d includes half of the sample delay and the pulse width modulation period. When using ω _c as the bandwidth for the proportional regulator 62 ', the proportional gain K _p is determined as follows.

이다. 그 경우

이다. 이러한 예에서, L은 3상 등가물의 인덕턴스의 두 배이다. 결과로 나타나는 위상 여유는 비례 조절기의 경우에 60°보다 크다. 큰 대역폭이 요구되는 경우, 이러한 개시 내용의 효과를 아는 당업자는 더 큰 대역폭을 얻기 위해 더 작은 위상 여유를 사용하는 방법을 알 것이다.Closed loop transfer function

to be. In that case

to be. In this example, L is twice the inductance of the three phase equivalent. The resulting phase margin is greater than 60 ° in the case of proportional regulators. If large bandwidths are required, those skilled in the art who know the effects of this disclosure will know how to use smaller phase margins to obtain larger bandwidths.

The output of the current regulator 38 is provided to a multiplier 80 in the bus voltage regulator 42. The other input 82 to the multiplier 80 is the actual line voltage measurement. The output of multiplier 80 is provided to summer 84, which includes a load power input 86 to the negative input of summer 84. A regulator function block 88 is shown that provides DC bus voltage regulation in a generally known manner. In this example, the controller 30 operates in response to a single phase input and the bus voltage regulator provides an output suitable for this purpose. In this example, the following equation is true.

The input power using a single-phase power supply is sine pie, so the average value in this example is used for the bus voltage. As an example, the average when V _ac is the maximum voltage and I is the amplitude of the line current is .5 (V _ac I). Thus, the bus voltage PI regulator design can be based on the following relationship.

In one example, DC bus voltage regulator 42 may be designed as shown schematically in FIG. The relationship shown in FIG. 5 includes a proportional gain K _p and an integral gain K _i . These can be determined based on the following relationship.

As an example, the current regulator bandwidth is greater than the DC bus voltage regulator bandwidth such that the open loop transfer function satisfies the following at the crossover frequency.

이고, 위상 방정식으로부터:

이다. 이러한 두 개의 방정식으로부터 K_p 및 K_i 는 다음과 같이 해를 구할 수 있다.From the magnitude equation:

And from the phase equation:

to be. From these two equations, K _p and K _i can be solved as follows.

,

,

,

,

In one example, pulse width modulation is used to provide current to the controller 30 in a manner useful for controlling the drive machine 22 responsive to single phase power. In one example, the pulse width modulation switching function applied to the R input 46 and the S input 48 is complementary. In this example, R input 46 is connected to a positive bus, while S input 48 is connected to a negative bus. In this way, the available voltage range from the bus can be fully utilized.

은 R 입력부(46)를 위한 듀티비이다. d_r은 캐리어 주기 동안 R 입력부(46)가 작동되는 시간량을 나타낸다. V^*는 전술한 피드 포워드함을 포함하는, 펄스 폭 변조 생성기에 제공되는 전압 기준이다. S 입력부(48)를 위한 듀티비인 d_s는 1-d_r으로 표현될 수 있다. T 입력부(44)에 0 볼트가 제공되도록, 이러한 예에서 바람직하게는 .5의 듀티비(d_t)가 T 입력부(44)에 제공된다.One exemplary pulse width modulation scheme includes using a duty ratio d located between 0 and 1. In this example, a value of zero means that the associated phase is connected to the negative bus for the entire pulse width modulation cycle. In this example, 1 means that the associated phase is connected to the positive bus for the entire pulse width modulation cycle. As an example, the following relationship is useful.

Is the duty ratio for the R input 46. d _r represents the amount of time the R input 46 is operated during the carrier period. V ^* is the voltage reference provided to the pulse width modulation generator, including the feed forward box described above. The duty ratio d _s for the S input unit 48 may be represented by 1-d _r . In this example, a duty ratio d _t of .5 is preferably provided to the T input 44 so that 0 volts is provided to the T input 44.

By using estimates of quadrature and direct phase components based on single phase voltages, the disclosed example enables the use of configurations designed to operate three phase power even at single phase power input. Providing the current regulator's D-axis or direct component in a feed forward manner minimizes errors and allows the disclosed example to operate based on single phase power.

Although the disclosed example has been expressed in the context of providing power to a drive machine for an elevator system, the present invention need not be limited to the elevator system.

The above description is illustrative in nature and not restrictive. Modifications and variations of the disclosed embodiments that are not necessarily departing from the spirit of the invention will be apparent to those skilled in the art. The legal protection scope of the present invention can only be determined by examining the appended claims.

1 is a schematic diagram illustrating selected portions of an elevator system incorporating a three-phase device and a power device designed according to an embodiment of the present invention.

2 is a schematic diagram illustrating selected portions of one exemplary converter interface useful in embodiments of the present invention.

3 is a schematic diagram illustrating one exemplary single phase control scheme useful in an embodiment of the invention.

4 is a schematic diagram illustrating one exemplary current regulator model useful in embodiments of the present invention.

5 is a schematic diagram illustrating a model of one exemplary voltage regulator useful in an embodiment of the present invention.

Claims (12)

A converter device for providing power to a three phase device using single phase input power, A phase locked loop using an estimated direct component and an estimated quadrature component based on the single phase input power, the phase locked loop having an R phase input, an S phase input and a T phase input The T phase input is set to 0 volts and the R phase input and the S phase input are coupled to a lead of the single phase input power; And a switch for selectively isolating said T phase input. 2. The converter device of claim 1 further comprising a current regulator coupled to the phase locked loop portion to use the estimated direct component as a feed forward input. 2. The converter device of claim 1, wherein the phase locked loop portion uses the measured voltage of the single phase input power as the estimated direct component. 2. The converter device of claim 1, wherein the phase locked loop portion uses a numerical derivative of the estimated direct component as the estimated orthogonal component. 5. The converter device of claim 4, wherein the phase locked loop portion uses a numerical derivative with scaled amplitude and a scale applied to the amplitude of the numerical derivative is determined based on the frequency of the single phase input power. 6. The scale of claim 5 wherein the scale applied to the amplitude of the numerical derivative comprises a first scale and a second scale, and wherein the first scale is applied to the amplitude of the numerical derivative when the frequency is greater than 55 Hz, and the frequency is 55 Hz. If less than the second scale is applied to the amplitude of the numerical derivative. A method of operating a three phase device using single phase input power, Estimating a direct component and an orthogonal component based on the single phase input power; Coupling one of the inputs to zero volts using a phase locked loop with a three phase input and coupling the other two inputs to a lead providing the single phase input power, respectively. 8. The method of claim 7, comprising estimating the direct component based on the measured voltage of the single phase input power. 8. The method of claim 7, comprising estimating the orthogonal component based on the numerical derivative of the direct component. 10. The method of claim 9 including scaling the amplitude of the numerical derivative based on the frequency of the single phase input power. 11. The method of claim 10, wherein scaling the amplitude of the numerical derivative comprises using a first scale when the frequency is above 55 Hz and using a second scale when the frequency is below 55 Hz. . 8. A method according to claim 7, comprising adjusting the current supplied to operate the three-phase device using a direct component as a feed forward input for current regulation.

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