RU2309526C2 - Method for controlling bridge inverter with two-sided pulse-width modulation and device for realization of the method - Google Patents

Abstract

FIELD: converting equipment, possible use for bridge inverters with one-sided pulse-width modulation, operating in consumption and energy recuperation modes.

SUBSTANCE: in the method for controlling bridge inverter with two-sided pulse-width modulation and device for its realization, energy consumption mode is realized by enabling key elements of required diagonal of key elements block, recuperation mode is realized by exclusion of all key elements, and pause mode is realized by enabling one of key elements of bridge inverter.

EFFECT: expanded functional capabilities.

2 cl, 2 dwg

Description

The invention relates to automatic control and is intended for bridge inverters with two-sided pulse-width modulation, the key elements of which are shunted by reverse diodes operating in the modes of consumption and energy recovery.

A device for controlling an inverter is known, in which a pulse-width modulator comprising a carrier frequency generator, pulses of which synchronize a sawtooth voltage block with a direct and inverse output, two comparators, at the output of which identical shifted by 180 email hail. pulse-width modulated signals, the duty cycle of which is formed by comparing the sawtooth voltages with the reference signal, the node for determining the voltage polarity of the reference, two delay elements forming a direct and inverse sign of the voltage polarity of the reference with a delay on the leading edge, control signals for each key element of the inverter are formed from modulated signals and signals of the sign of polarity [1].

The well-known pulse-width modulator allows you to control the inverter by means of two-sided unipolar period modulation. To exclude the through current mode in this modulator, the output voltage sign signal allows the inclusion of only the required key elements, and to exclude the through current when changing polarity, the enable signal is generated with a delay sufficient to lock the included key elements.

The disadvantage of this modulator is the need to generate output voltage sign signals, the delay of formation of which distorts the output voltage when its polarity is changed, in addition, for inverters with key elements shunted by reverse diodes, controllability in the energy recovery mode is not provided.

The closest technical solution, selected as a prototype, is a method of controlling an inverter with two-sided pulse-width modulation, containing a bridge block of key elements and an LC filter, which consists in the formation of two pulse-width modulated signals (according to the number of racks of the bridge inverter), which form from a control signal to turn on the voltage of positive polarity, a control signal to turn on the voltage of negative polarity, a control signal to turn off the voltage of the positive hydrochloric polarity control signal to switch off the voltage of negative polarity [2].

The known method of controlling an inverter with two-sided pulse width modulation allows you to control the output voltage by unipolar during the period of modulation of the supply voltage, while in the bridge block of key elements switch the key elements of only one rack.

A disadvantage of the known control method for bridge inverters with key elements shunted by reverse diodes is that it does not provide controllability in the energy recovery mode.

The purpose of the technical solution is to expand the functionality of a bridge inverter with key elements shunted by reverse diodes to operate in energy recovery mode.

This goal is achieved by the fact that to control the block of key elements, four width-modulated signals are generated (according to the number of key elements), which are formed taking into account the current sign of the LC filter choke from the control signal to turn on the voltage of positive polarity, the control signal to turn on the voltage of negative polarity a control signal for disconnecting a voltage of positive polarity and a control signal for disconnecting a voltage of negative polarity.

Figure 1 shows a diagram of a bridge inverter with two-sided pulse-width modulation; figure 2 - device (modulator) that implements the proposed control method.

, сигнал положительной полярности тока дросселя I(+) и сигнал отрицательной полярности тока дросселя I(-), формирователь управляющих сигналов 3 формирует из сигнала напряжения задания U_on, сигнала, пропорционального значению входного напряжения питания инвертора U_n, сигнала, пропорционального значению выходного напряжения инвертора U_n, синхронизирующего сигнала С и сигнала

пульсирующей составляющей тока дросселя управляющий сигнал F(+) для включения напряжения положительной полярности, управляющий сигнал F(0+) для отключения напряжения положительной полярности, управляющий сигнал F(-) включения напряжения отрицательной полярности и управляющий сигнал F(0-) для отключения напряжения отрицательной полярности, модулятор 5 формирует широтно-модулированные сигналы Y_1H, Y_1B, Y_2H, Y_2B из сигналов I(+), I(-), F(+), F(0+), F(-) и F(0-), широтно-модулированные сигналы Y_1H, Y_1B, Y_2H, Y_2B поступают на управляющие входы блока ключевых элементов 1, на входные шины блока ключевых элементов 1 поступает напряжение питания U_п, выходные шины блока ключевых элементов 1 соединены с входными шинами LC-фильтра 2, выходные шины LC-фильтра 2 являются выходными шинами мостового инвертора.A bridge inverter with two-sided pulse width modulation (Fig. 1) contains a block of key elements 1, an LC filter 2, a driver of control signals 3, a processing unit of the current signal 4, a modulator 5, a processing unit of the current signal 4 generates an LC- from the current signal filter 2 signal of the pulsating component of the inductor current

, the signal of positive polarity of the inductor current I (+) and the signal of negative polarity of the inductor current I (-), the driver of the control signals 3 generates from the signal voltage of the reference U _on , a signal proportional to the value of the input voltage of the inverter U _n , a signal proportional to the value of the output voltage inverter U _n , clock signal C and signal

the pulsating component of the inductor current control signal F (+) to turn on the voltage of positive polarity, control signal F (0+) to turn off the voltage of positive polarity, control signal F (-) to turn on the voltage of negative polarity and control signal F (0-) to turn off the voltage negative polarity, the modulator 5 generates the width-modulated signals Y _1H , Y _1B , Y _2H , Y _2B from the signals I (+), I (-), F (+), F (0+), F (-) and F (0-∞), the pulse-modulated signals _{Y 1H, Y 1B, Y 2H} , Y 2B supplied to the control inputs of the block key element 1, the input key element bus unit 1 receives the supply voltage U _n, the output bus unit key elements 1 are connected to the LC-filter 2 input buses, output buses LC-filter 2 are the output lines of the bridge inverter.

The essence of the invention lies in the fact that the energy consumption mode at a positive output voltage is realized by turning on the key elements of the positive diagonal of the block of key elements 1, and the pause mode by turning off one of the included key elements, while the current of the LC-filter choke 2 is closed by the "on key element - reverse diode ”, the recovery mode is carried out by switching off all key elements, while the current of the choke of the LC filter 2 is closed by the circuit“ reverse diode - power source - reverse diode ”, And the pause mode - by switching on one of the key elements of the negative diagonal, respectively, the energy consumption mode at negative voltage is realized by turning on the key elements of the negative diagonal of the block of key elements 1, the pause mode - by turning off one of the included key elements, the energy recovery mode - by turning off all key elements , pause mode - by switching on one of the key elements of the positive diagonal.

The control of the block of key elements of the bridge inverter is carried out according to the following algorithm:

If there is a signal I (+) of positive polarity of the current of the LC filter choke 2, the positive polarity voltage is switched on to the output of the key element block 1 by turning on the key elements Y _1B , Y _2H (the name of the key element corresponds to the name of its control signal) when the control signal F ( +); disconnection of voltage of positive polarity from the output of the block of key elements 1 is carried out by disconnecting the key element Y _1B when the control signal F (0+); switching on the voltage of negative polarity to the output of the block of key elements 1 is carried out by disconnecting all key elements when the control signal F (-) appears; disconnection of voltage of negative polarity from the output of the block of key elements 1 is carried out by switching on the key element Y _2H when the control signal F (0-) appears.

If there is a signal I (-) of negative polarity of the current of the throttle of the LC filter 2, the voltage of negative polarity is switched on to the output of the block of key elements 1 by turning on the key elements Y _1H , Y _2B when the control signal F (-) appears; disconnection of negative polarity voltage from the output of the block of key elements 1 is carried out by disconnecting the key element Y _2B when the control signal F (0-) appears; switching on the voltage of positive polarity to the output of the block of key elements 1 is carried out by disconnecting all key elements when the control signal F (+) appears; disconnection of voltage of positive polarity from the output of the block of key elements 1 is carried out by switching on the key element Y _1H when the control signal F (0+) appears.

A device (modulator 5) (Figure 2) that implements the proposed method for controlling a bridge inverter with one-sided pulse-width modulation, contains: two modulation nodes 6, 7, each of which is designed to control one rack of a block of key elements 1 of a bridge inverter and consists of two RS-flip-flops 8, 9, two logic elements 3-I 10, 11 and two delay elements 12, 13, has two output buses B, H, three control inputs F _y1 , F _y2 , F _y3 and two mode inputs F _p1 , F _p2 , the direct output of the RS-flip-flop 8 is connected to the output bus B of the modulation node, the output logic element 10 is connected to the S input of the RS-flip-flop 8, the first input of logic element 10 is connected to the inverse output of the RS-flip-flop 9 through a delay element 12, the second input of logic element 10 and R the input of the RS-flip-flop 9 are connected to the control input F _{y1 of} the modulation node , the third input of the logic element 10 is connected to the mode input F _{p1 of} the modulation node, R the input of the RS trigger 8 is connected to the control input F _{y2 of} the modulation node, the direct output of the RS trigger 9 is connected to the output bus H of the modulation node, the output of the logic element 11 is connected to S RS trigger input 9, first the input input of the logic element 11 is connected to the inverse output of the RS-flip-flop 8 through the delay element 13, the second input of the logic element 11 is connected to the control input F _{y3 of} the modulation node, the third input of logic element 11 is connected to the mode input F _{p2 of} the modulation node, the output bus of the node B modulation 6 is connected to the output bus Y _1B , the output bus H of the modulation node 6 is connected to the output bus Y _1H , the output bus B of the modulation 7 is connected to the output bus Y _2B , the output bus H of the modulation 7 is connected to the output bus Y _2H , control input F _y1 node mode 6 is connected to the control signal bus F (+), the control input F _{y1 of} the modulation unit 7 is connected to the control signal bus F (-), the control input F _{y2 of} the modulation unit 6 and the control input F _y3 , modulation unit 7 are connected to the control signal bus F (0+), the control input F _{y3 of} the modulation node 6 and the control input F _{y2 of} the modulation node 7 are connected to the control signal bus F (0-), the mode input F _{p1 of} the modulation node 6 and the mode input F _{p2 of} the modulation node 7 are connected to the bus signal I (+), F _p2 modal input modulation unit 6, and F _p1 modal input modulation unit 7 are connected to the bus sig ala I (-).

A device (modulator 5) that implements the proposed method for controlling a bridge inverter with two-way modulation works as follows: at the inputs of RS-flip-flops 8, 9 of modulation nodes 5, 6, signals are generated in accordance with the logical expression:

where F (+) and F (-) are control signals for switching on the positive and negative polarity of the supply voltage, are formed by the control unit 3 of the bridge inverter. F (0+) and F (0-) - control signals for switching off the positive and negative polarity of the supply voltage, are formed by the control unit 3 of the bridge inverter; the output signals Y _1B , Y _{2H of the} pulse-width modulator control the state of the key elements of the bridge inverter generating voltage of positive polarity, and the signals Y _1H , Y _2B - negative polarity, while the signals Y _1B , Y _1H control the state of the key elements of the first rack of the bridge inverter, and the signals Y _2B, Y _2H - the second (the subscript indicates the address of the output signal), to avoid a short circuit in the racks key elements bridge inverter introduced lockup protection circuit for the inclusion of two key elements of one racks, protection is carried out by the first input of logic elements 10, 11 in each modulation node 6, 7 by prohibiting the signal from passing to the S-inputs of RS-flip-flops 8 in the presence of signal H and by inhibiting the signal from passing to the S-inputs of RS-flip-flops 9 in the presence of signal B, protection is carried out with a delay (delay elements 12, 13), sufficient to reliably disable the included key element.

Thus, the control of the block of key elements 1 of the bridge inverter by the formation of four width-modulated signals (for separate control of each key element) made it possible to generate the output voltage not by switching the rack of key elements, but by turning on and off only one key element necessary for generating the output voltage, which excludes the possibility the occurrence of through currents, and the use of signals of the sign of polarity of the current of the choke of the LC filter 2 allowed to control energy recovery.

Literature

1. USSR author's certificate No. 1603509, Н02М 7/48 10/30/1990.

2. RF patent No. 2223529, G05В 13/02, G05F 1/56, Н03R 7/08 02/10/2004.

Claims (2)

1. A control method for a bridge inverter with two-sided pulse width modulation, which consists in generating a control signal for turning on the voltage of positive polarity, a control signal for turning off the voltage of positive polarity, a control signal for turning on the voltage of negative polarity, a control signal for turning off the voltage of negative polarity , characterized in that it additionally generates signals of positive and negative polarity of the current of the throttle LC filter, when the signal p the negative polarity of the LC filter choke current; switching on the voltage of positive polarity to the output of the block of key elements by turning on the key elements of the positive diagonal when a control signal appears to turn on the voltage of positive polarity, turning off the voltage of positive polarity from the output of the block of key elements by disconnecting one key element when the control signal appears to turn off the voltage of positive polarity, turn on the voltage negative polarity to the output of the block of key elements is carried out by turning off all key elements when a signal appears to turn on the voltage of negative polarity, disconnecting the voltage of negative polarity from the output of the block of key elements is done by turning on one key element of the positive diagonal when a control signal appears to turn off the voltage of negative polarity, respectively, when the signal negative polarity of the LC filter choke current The output block of the key elements is switched on by switching on the key elements of the negative diagonal when a control signal appears to turn on the voltage of negative polarity, disconnecting the negative polarity voltage from the output of the block of key elements is done by turning off one key element when the control signal appears to turn off the voltage of negative polarity, turning on the voltage of positive polarity the output of the block of key elements is carried out by disabling all yuchevyh elements when a control signal for switching the voltage of positive polarity, disabling the voltage of positive polarity from the output of the key elements of the block is carried out by including a key element in the negative diagonal control signal to turn off when a voltage of positive polarity. 2. A device for controlling a bridge inverter that implements the control method according to claim 1, contains two modulation nodes, each modulation node is designed to control one rack of a block of key elements of a bridge inverter and consists of two RS-triggers, two 3-I logic elements, and two delay elements, has two output buses, three control inputs and two mode inputs, the direct output of the first RS-trigger is connected to the first output bus of the modulation unit, the output of the first 3-I logic element is connected to the S-input of the first RS-trigger, the first the first input of the first 3-I logic element is connected to the inverse output of the second RS-trigger via the first delay element, the second input of the first 3-I logic element and the R-input of the second RS-trigger are connected to the first control input of the modulation node, the third input of the first logic element 3-I is connected to the first mode input of the modulation node, the R-input of the first RS-trigger is connected to the second control input of the modulation node, the direct output of the second RS-trigger is connected to the second output bus of the modulation node, the output of the second logic element 3-I inen with the S-input of the second RS-trigger, the first input of the second logic element 3-I is connected to the inverse output of the first RS-trigger through the second delay element, the second input of the second logic element 3-I is connected to the third control input of the modulation node, the third input of the second logic element 3-I is connected to the second mode input of the modulation node, the output buses of the modulation nodes are connected to the control inputs of the block of key elements, the first output bus of the first modulation node and the second output bus of the second modulation node are dined with the positive diagonal control inputs of the block of key elements, and the second output bus of the first modulation node and the first output bus of the second modulation node are connected to the negative diagonal control inputs of the block of key elements, the first control input of the first modulation node is connected to the control signal bus to turn on the voltage of positive polarity , the first control input of the second modulation node is connected to the control signal bus to turn on the voltage of negative polarity, the second control the input input of the first modulation node and the third control input of the second modulation node are connected to the control signal bus to disconnect the positive voltage, the third control input of the first modulation node and the second control input of the second modulation node are connected to the control signal bus to disconnect the negative voltage, the first mode input of the first node modulation and the second mode input of the second modulation node are connected to the bus for a signal of positive polarity of the LC filter choke current, the second mode input of the first la modulation and the first input of the second modal modulation unit connected to the bus for the LC-filter inductor current negative polarity signal.

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