RU2681347C1 - Generator of multi-phase emf system with reduced twice power tongs - Google Patents

Abstract

FIELD: electrical equipment.SUBSTANCE: invention relates to the electrical equipment. For this, the following functional units can be distinguished in the proposed device: 1. Control unit. Provides cyclical, alternate supply of control impulses of duration TI = T / n with a predetermined period T, which control the opening of electronic power switches located in the switching unit; 2. Switching unit with a group of logic elements. It provides connection using power tongs to the output terminals of the switching unit of the voltage sources generated by the power supply unit. Group of logical elements OR, located in the switching unit, allows to reduce the number of power switches in two (or more) times; 3. Power supply unit includes a set of constant voltage sources of a given value. Each voltage source in the sequence specified by the control unit is connected for a time interval by TI tongs located in the switching unit to the output terminals of the switching unit.EFFECT: technical result characterizes a decrease in dimensions and weight of the device, an increase in energy characteristics due to a reduction in losses in power switches thereof, and an increase in reliability.1 cl, 7 dwg, 2 tbl

Description

FIELD OF THE INVENTION

1.1 Scope

The invention relates to the field of electrical engineering. The device is designed to generate a multiphase system of voltages of the required frequency, voltage value and number of phases.

The device can be used both in stationary and mobile systems (robotics) to power multiphase AC motors, as well as to power other multiphase consumers of electric energy with a different frequency than the standard power supply. The use of logical elements in the device circuit allows reducing the number of power keys used for switching by two (or more) times in comparison with the previously proposed device [1]. This allows you to reduce the size and weight of the device, increases its energy characteristics by reducing losses in power switches, increases the reliability of the device. These characteristics are important for mobile devices, where dimensions and weight are essential.

II. State of the art

II.1 Comparison with Prior Art

The aim of the invention is to develop a device for generating a multiphase system of voltages of the required frequency, voltage value and number of phases based on the use of pulse technology, which differs from the previously proposed device by reducing two (or more) times the number of power switches in the switching unit.

Symmetry Properties of a Sinusoidal Function A sinusoidal function has the following symmetry properties:

3. e(t)= -e(t+T/2) для 0<t<T/2.

3. e (t) = -e (t + T / 2) for 0 <t <T / 2.

These symmetry properties are also valid for the approximating function of FIG. 1 represented by a sequence of impulse functions.

These properties allow for the approximation of a sinusoidal function to use a limited number of discrete values of the impulse functions.

Distinctive properties of the proposed device

The proposed device for generating a multiphase voltage system differs from that described in [1] in that:

- to reduce the number of power switches by two (or more) times in the switching unit, the symmetry property of the sinusoidal function is used. The positive and negative half-waves of the sine wave are symmetrical, and each of the half-waves is symmetrical about the vertical axis, which is behaved through the extreme value of the function;

- the approximating sinusoid function, consisting of a sequence of impulse functions, also possesses the indicated symmetry property. We take the number of impulse functions on the period of the sinusoidal function T equal to n, and the number of phases of the generator m. Then the number of power switches needed for switching these impulse functions will be n⋅m;

- the number of impulse functions with the same amplitude values at the positive half wave of the sine wave will be equal to n / 4 and the same number will be at the negative half wave of the sine wave. Together this amounts to n / 2. For switching impulse functions, the set of which approximates the sinusoidal phase voltages, in a multiphase system, using the symmetry properties, m⋅n / 2 keys will be required;

- the proposed device uses logical elements OR (in the figure of the switching unit of Fig. 7, the sign 1 is used). The input of the OR logic element receives signals from the decoder of the control unit, which correspond to pulses with the same amplitude values. The signal from the output of each logic element is fed to the input of the power key to put it in the open state for the duration of the input control signal;

- the number of keys required for switching impulse functions when using logic elements will be m⋅n / 2. This is half the number of keys in a circuit that does not use logic elements. In some cases, the number of keys may be less than m⋅n / 2.

- The sequence of pulses with the required amplitude values in each phase of the generator is set by the control device and the switching circuit on the controlled keys, the control signals to which are fed from the outputs of the OR logical elements.

As controlled keys, triacs, transistor switches of the required polarity based on MOS transistors and IGBT transistors, thyristors can be used. The switching matrix together with a group of logical elements OR can be implemented using the technology of manufacturing microcircuits.

III. Disclosure of the invention

III. 1 Approximation of a sinusoidal function by a sequence of impulse functions

In FIG. Dotted line 1 represents the segment of the sinusoidal function in the interval 0..2π and the approximation of this function by a sequence of impulse functions when the period of the function is divided into n = 12 time intervals. In the figure of FIG. 1 shows the amplitude values of each of the pulses E1, E2, E3, -E1, -E2, -E3. Table 1 contains the amplitude values of the pulses for each time interval in the period for each phase of the three-phase system.

The voltage values E ₁ , E ₂ , E ₃ are shown in the figure of FIG. one.

From the figure shown in FIG. 1, it follows that to obtain a stepwise approximating function, it suffices to use n / 2 sources of constant voltage, which are switched on for the time interval TI in the corresponding time intervals. For the one shown in FIG. 1 case n = 12

EMF source E1 is turned on for a time interval TI in the first or sixth time intervals, source E2 is turned on in the second or fifth time intervals, source E3 is turned on in the third and fourth time intervals, source E6 = -E3 is turned on in the ninth and tenth time intervals, source E5 = -E2 is included in the eighth and eleventh time intervals, the source E4 = -E1 is included in the seventh and twelfth time intervals.

We show that the number of power switches may be less than n / 2. In the figure of FIG. Figure 2 shows the approximation of a sinusoidal function by a sequence of impulse functions at n = 24. In this case, the following designations of EMF pulses are accepted:

E ₂ = -E ₁ , E ₄ = -E ₃ , E ₆ = -E ₅ , E ₈ = -E ₇ , E ₁₀ = -E ₉

Table 2 contains the amplitude values of the impulse functions for each time interval from 1 to 24 (according to the number of impulse functions) for each of the phases of the three-phase EMF system. Each time interval corresponds to a step of 15 ° sinusoidal function.

From table 2 it follows that the value of E ₀ in each phase occurs 4 times. Consequently, the sinusoidal EMF function of each phase can be represented not with n / 2 = 12 pulse functions, but with

11 pulse functions with amplitudes E0, E1, E2, E3, E4, E5, E6, E7, E8, E9, E10. Accordingly, in this case, 11 power keys will be needed to switch these sources.

III.2. Device block diagram

The block diagram of the device is shown in the figure of FIG. 3.

In the figure of FIG. 3 shows the following device blocks:

1. The control unit. Provides a cyclic, with a given period T, alternate supply of control pulses that control the opening of electronic keys located in the switching unit;

2. The switching unit provides connection to the output terminals of the switching unit of the sources generated by the power supply.

3. The power supply generates constant voltage of a given value. The voltage of the sources are connected by switches located in the switching unit to the output terminals of the switching unit. Distinctive for the proposed device is that voltages of positive and negative polarity are formed as a result of a series connection of the same voltage sources. As power sources can be taken galvanic batteries, rechargeable and capacitor banks, etc.

In the figure of FIG. 3 shows a structural diagram of the device with an indication of the external poles of the blocks, with which the blocks are connected and controlled, and the numbering of the blocks is shown in accordance with the general circuit diagram:

- 14 - control unit;

15 - switching unit;

16 - power supply;

In the figure of FIG. 3 shows the poles with which the blocks interact and the poles 6 and 13, with which the device is controlled. The pole numbers are indicated in accordance with the general circuit diagram of the device. The signal for starting the device is entered using pole 6. The number of time intervals i, into which the period of the sinusoidal function T is divided, is entered using pole 13. Using the poles 8 ₁ ... 8 _n, the control unit and the switching unit are connected, using poles 11 ₁ ... 11 _{n / 2} the power supply is connected to the switching unit, the poles 12 ₁ ... 12 _m are output, the load is connected to them.

III.3 Control unit

The circuit of the control unit is shown in the figure of FIG. 4. The control unit 14 is designed to generate control pulses as a result of creating a sequence of rectangular pulses of a given duration TI and supplying these signals to the inputs of the logic elements OR 9 located in the switching unit. The block forms a pulse sequence cyclic with a period T. The value of T is equal to the period of the sinusoidal function. The number of pulses in period T is n,

duration of one pulse TI. The values of n and TI are selected based on considerations of ensuring the required error of approximation of the sinusoidal function by a sequence of rectangular impulse functions and the cost of implementing the device. With an increase in n and a decrease in TI, the error decreases and the cost increases.

In the figure of FIG. Figure 5 shows the values of the control pulses for two time instants - the fourth and fifth pulses in a row within the same period T. In Fig. 5a shows the fourth pulse. In the time interval 3TI≤t≤4TI, the value of the control pulse is 1, and for the remaining time intervals, the value of the control pulse is 0. In Fig. 5b shows the fourth fifth pulse following the fourth, acting on a time interval of 4TI≤t≤5TI. In this time interval, the value of the control pulse is 1, and for the remaining time intervals, within the period T, it is 0. In these expressions, TI is the value of the time interval in which the pulse acts. The relation T = nTI is valid, where n is the number of time intervals in one period T. For the sinusoidal function shown in the figure of FIG. 1 the number of time slots is 12.

Using electronic keys located in the switching unit, the EMF sources generated by the power supply are connected at time points specified by the control unit in accordance with the specified algorithm to the output poles of the switching unit. Switching is carried out in the open state of the key. The duration of the open state of each key is equal to TI. The number k of discrete EMF values for specific values of n = 12 and the number of phases m = 3 are shown in table 1.

The schematic diagram of the control unit is shown in the figure of FIG. four.

The block is implemented on elements 1-7. It contains a clock pulse generator (GTI) 1, a logic element AND 2, a counter 3 of the number of pulses on the period T of the periodic function, a comparison circuit 4, register 5, a decoder 7 with the number of outputs equal to n - the number of pulse functions on the period T. Output poles the control unit 8 ₁ ... 8 _{n are} connected to the logic element 9r, s located in the switching unit, where r = 1 ... m, s = 1..n / 2, m is the number of phases. The device is started by applying a signal at input 6. At input 13, a code is written for the number of time intervals n.

The output of the GTI 1 is connected to the first input of the And 2 element, the second input of which is connected to the first input 6 of the device, and the output is connected to the first input of the counter 3, the output of which is connected to the input of the decoder 7 and to the first input of the comparison circuit 4, the second input of which is connected to the output of the register 5, and the output to the second input of the counter 3, the input of the register 5 is connected to the input 13 of the device, the outputs of the decoder 7 are connected to the inputs 8 ₁ ..8 _n , through which the control unit is connected to the switching unit.

III.4 Power Supply

The power supply is designed to generate a set of constant sources of constant voltage, the EMF values of which are equal to the amplitude values of the pulses of the approximating sinusoid function.

For the case m = 3, n = 12, according to the drawing of FIG. 1, these are E1, E2, E3, E4 = -E1, E5 = -E2, E6 = -E3.

The power supply can be made in various versions, depending on the purpose of the device (stationary or mobile), load power, technical requirements.

Let us consider the implementation of a power supply for the case of powering mobile devices and using small-sized, single-type constant voltage sources with the same voltage values as power sources. It can be - galvanic power supplies of types R, LR, SR, CR of classes D, C, AA, AAA, PP3, rechargeable or capacitor batteries. The power supply circuit is shown in the figure of FIG. 6. The power supply through the poles 11 ₁ , 11 ₂ , 11 ₃ , 11 ₄ , 11 ₅ , 11 _{6 is} connected to the switching unit. Power supplies 18 ₁ ... 18 _{n / 4 of} positive polarity are connected to each other in series. For n = 12, these are sources 18 ₁ , 18 ₂ , 18 ₃ . Sources of negative polarity 18 _{n / 4 + 1} ..18 _{n / 2 are} connected in series. For n = 12, these are sources 18 ₄ , 18 ₅ , 18 ₆ . By pole January ₁₁ connects a power source with voltage E ₁ = E, the pole February ₁₁ are connected two series connected source so that their voltage is E ₂ = 2E _1, the pole on March _11, are connected three series connected source to each source voltage E ₁ , their total voltage is E ₃ = 3E ₁ . By pole April ₁₁ connects the power supply with a voltage of E = -E _4, the pole on May ₁₁ connect two series connected source with a voltage of each source - E, the total voltage E = ₅ -2E _1, the pole ₁₁ June connected three series-connected source with the voltage of each - E, their total voltage is E ₆ = -3E. This allows one to obtain voltages that are multiples of the voltage of one source E. The sequence of sources with these voltage values allows us to approximate the sinusoidal phase voltages. Table 1 contains the voltage values of pulsed sources for the number of time intervals n = 12 and the number of phases m = 3.

The transformer circuit of the power supply unit when powered by AC power and the circuit of the power supply unit from the battery using the DC / DC converter are described in [1].

III.5 Switching unit

The circuit of the switching unit for m = 3, n = 12 is shown in the figure of FIG. 7. Using the switching unit 15, the voltage sources coming from the power supply 16, through the poles 11 ₁ ..11 _{n / 2 are} connected by power switches 10 _rs at the appropriate time intervals

(k-1) TI≤t≤kTI, k = 1,2, ... n

to the output poles of block 12 ₁ ... 12 _m . In the written expression, TI is the duration of the time interval of one voltage pulse, n is the number of time intervals in the period T, m is the number of phases of the generator, n is the number of time intervals in the period T. Switching is performed using controlled electronic keys 10 _{r, s} , where r = 1..m, s = 1..n / 2. The pulses that control the open state of each electronic key come from the poles 8 ₁ ... 8 _n of the control unit by means of the logic elements 9 _{r, s} , r = 1..m, s = 1..n / 2, to the control electrodes of the power switches.

For phase 1, the pulse from the control unit from the pole 8 ₁ enters the switching unit 15 to the first input of the OR gate 9 _1,1 to the second input of the logic element 9 _1,1 receives a control pulse in the sixth time interval from the pole 8 ₆ . From the output of the logic element 9 _1,1 to the input of the power key 10 _1,1 receives a control pulse and opens the key for the time interval TI. In the open state of the switch 10 _{1.1, the} voltage of the source E1 through the pole 11 _{1 is} fed to the output of the switching unit to the output pole 12 ₁ .

For phase 2, the pulse from the control unit from the pole 8 ₂ enters the switching unit 15 to the first input of the logic element OR 9 ₂ , ₁ to the second input of the logic element 9 _2,1 receives a control pulse in the second time interval from the pole 8 ₂ . From the input of the OR logic element 9 _{2.1, the} control pulse is supplied to the control electrode of the power switch 10 ₂₁ . In the open state of the switch 10 _2.1 , the source voltage E6 = -E3 through the pole 11 _{6 is} fed to the output of the switching unit to the output pole 12 ₂ .

For phase 3, the pulse from the control unit from the pole 8 ₁ enters the switching unit 15 to the first input of the logic element 9 _3.1 to the second input of the logic element 9 _3.1 receives a control pulse in the tenth time interval from the pole 8 ₁₀ . From the input of the OR logic element _{3,11, the} control pulse is supplied to the control electrode of the power switch 10 ₃₁ . In the open state of the switch 10 _{3.1, the} voltage of the source E2 through the pole 11 _{2 is} supplied to the output of the switching unit to the output pole 12 ₃ .

The work of the remaining logic elements 9 _{r, s} and power switches 10 _{r, s} where r = 1..m, s = 1..n / 2, is similar to the described processes for phases 1, 2 and 3.

IV. Brief Description of the Drawings

FIG. 1 Approximation of a sinusoidal function by a sequence of impulse functions for n = 12

FIG. 2 Approximation of a sinusoidal function by a sequence of impulse functions for n = 24

FIG. 3 Block diagram of the device

FIG. 4 Schematic diagram of the control unit

FIG. 5 Charts of control pulses. In the figure of FIG. 5 a

the fourth pulse is shown, in the figure of FIG. 5b is the fifth impulse.

FIG. 6 Schematic diagram of the power supply for n = 12

FIG. 7 Schematic diagram of the switching unit for a three-phase source m = 3, n = 12

V. The implementation of the invention

Description of the operation of the device. In the initial state on register 5

at input 13, a code is written for the number of time intervals n. The period of the sinusoidal function T is divided into this number of intervals when the sinusoidal function is approximated by a sequence of impulse functions. On the counter 3, a zero code is stored (the reset input to zero on the counter 3 in Fig. 4 is not shown). The operation of the device begins after a start signal is supplied at input 6 of logic element And 2. After a start signal is supplied, pulses from the output of the clock pulse generator 1 through the open element And 2 begin to flow to the input of counter 3. The code from the output of counter 3 goes to the input of decoder 7. On the output of the decoder appears a single signal only at one of its n outputs. A single signal at the i-th (i = 1 ... n) output of the decoder 7 is fed to the input of the switching unit through one of the poles 8 _i , where

i = 1..n.

One of the poles 8 _i , in accordance with the logic specified in table 1, is connected to one of the inputs of the logic element 9 _rs (r = 1..m, s = 1..n / 2). The second pole of set 8 _{i is} connected to the second input of the logic element. So, for logic elements in the first phase 9 _{1, s} , s = 1..n / 2, the poles are connected to the inputs of the logic elements: to the logical element 9 _1,1 - the poles 8 ₁ and 8 ₆ , to the logical element 9 _1,2 poles 8 ₂ and 8 ₅ , to the logic element 9 _1.3 poles 8 ₃ and 8 ₄ , etc.

The outputs of the logic elements are connected to the control electrodes of the controlled keys 10r, s, where s is the number of the power source, r is the phase number from 1 to m. The inputs of the controlled keys are connected by the poles 11 _i , i = 1..n / 2, to the voltage sources E ₁ ..E _{n / 2} , and the outputs of the power switches are connected to the output poles of the switching unit 12 ₁ ..12 _m . In each time interval, only one constant voltage source from the set E ₁ ..E _{n / 2 is} connected to each output pole of the switching unit 12 ₁ ..12 _m . In the circuit diagram of the switching unit, the drawing of FIG. 7 shows the switching for a three-phase emf source when the number of time intervals in period T is n = 12. According to the table. 1, a first time slot to the pole on January ₁₂ (phase 1) connects a source of EMF E _1, February ₁₂ to the pole (the second phase) is connected emf source E _2, the pole ₁₂ March (third phase) is connected source E -E3 = _6. For other intervals from 2 to 12, switching is defined similarly.

Connection of power supplies 18 ₁ ..18 _{n / 2} with voltages E ₁ ..E _{n / 2} to the output poles of the switching unit 12 ₁ ..l2 _{m is} carried out using controlled electronic switches. The signals that control at the time moment TI = T / n the open state of the key are received from the output of the decoder of the control unit via poles 8 ₁ ..8 _n . The control unit sets the sequence of control pulses. The control pulse coming from the pole 8 _j , j = 1..n, is followed by the control pulse from the pole 8 _{j + 1} , until j + 1 becomes equal to n. After the termination of the pulse from the output 8 _{n, the} pulse 8 _{1 is} turned _on . In this case, the current value of the counter of the number of pulses 3 will coincide with the number n set with input 13, the counter is reset and the process is repeated.

VI. Literature

1. Patent No. 2016127384, IPC Н05В 1/00, 2017, L. P. Gavrilov EMF multiphase generator

Claims (1)

The generator of a multiphase EMF system with logic elements contains a power supply 16, a switching unit 15, a control unit 14, consisting of a clock pulse generator (GTI) 1, an element 2, a counter 3, a comparison circuit 4, a register 5, a start button of a device 6, a decoder 7, the input for setting the number of time intervals 13, the GTI output 1 is connected to the first input of the And 2 element, the start button of the device 6 is connected to the second input of the And 2 element, the output of the And 2 element is connected to the first input of the counter 3, the output of which is connected to the decoder input 7 and to the first input of the comparison circuit 4, the output of the comparison circuit 4 is connected to the second input of the counter 3, the register 5 is connected to the second input of the comparison circuit 4, the input 13 of which records the number of time intervals n on period T, from the output of the counter 3 pulses are fed to the input of the decoder 7, which is connected to the switching unit 15 with poles 8 ₁ ... 8 _n , the power switches 10 _{r, s} , r = 1 ... m are located in the switching unit, where m is the number of generator phases, s = 1 ... n / 2, the inputs of which are connected the poles 11 ₁ ... 11 _{n / 2} power supply unit 16 which comprises DC sources nap yazheniya 18 ₁ ... 18 _{n / 2,} power switches outputs 10 _{r, s} are connected to the poles 12 ₁ ... 12 _m, which are output to the device, characterized in that a switching unit incorporated group OR gate 9, _{r, s, r} = 1 ... m, s = 1 ... n / 2, while each of the two inputs of each of them at different time intervals receives control pulses from the outputs of the control unit 8 ₁ ... 8 _n , and the outputs of the logic elements are connected to the control electrodes of the power switches 10 _{r, s} with the result that each power switch is in the open position for the duration of their TI pulse than once during a period T, and twice each time transmits the same voltage values on the output device.

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