RU124458U1 - POWER MODULE - Google Patents

Abstract

1. A power module comprising two series-connected bi-directional current key nodes with a direct voltage blocking ability and series-connected inductor and first and second capacitors, with one terminal of the first key node connected to the first power terminal of the module, the other terminal of the first key node connected to one terminal of the second key node and the output of the throttle, another terminal of the second key node is connected to the second power terminal of the module, the connection point of the first and second capacitors It is connected to the third power terminal of the module, the other terminal of the second capacitor is connected to one of the first and second power terminals of the module, characterized in that the key nodes of the power module are made with reverse voltage blocking ability. 2. The module according to claim 1, characterized in that the key node contains the first and second key nodes and the first and second diodes, the anode of the first diode and the cathode of the second diode are combined and form one terminal of the key node, the first and second diodes are connected in series with one terminal of the same keys , the other conclusions of which are combined and form another conclusion of the key node. 3. The module according to claim 1, characterized in that the key node contains the first and second keys, each equipped with the same counter-parallel diode, the anodes of which are connected, and the cathodes form the same terminals of the key node. The module according to claim 1, characterized in that the key node contains a bridge circuit of four diodes and a key included in the diagonal of the bridge circuit between the connection points of the anodes and cathodes of the corresponding diodes, while the connection points of the anode and cathode are

Description

The utility model relates to power electronics, in particular, to converters with reduced dynamic losses in power semiconductor switches and can be used in circuits of autonomous current inverters and active rectifiers.

A known converter circuit in which soft shutdown of the main key nodes at zero current is provided using two additional key nodes and a sequential LC circuit (see US Pat. No. 5,486,752, publ. 23.01.1996).

The disadvantage of this solution is that the inclusion of the main key nodes remains rigid, which significantly increases the dynamic losses in the circuit.

The closest in technical essence is the power module (see RF application for invention No. 20111116247 dated 04/26/2011, decision on the grant of a patent dated 12/12/2011) containing two serially connected bidirectional key assemblies with direct voltage blocking ability, and in series connected throttle and first and second capacitors, with one terminal of the first key node connected to the first power terminal of the module, another terminal of the first key node connected to one terminal of the second key node and the terminal of the throttle, another the output of the second key node is connected to the second power output of the module, the connection point of the first and second capacitors is connected to the third power output of the module, the other output of the second capacitor is connected to one of the first and second power outputs of the module.

This solution provides soft switching of key elements in the DC and AC circuits of a wide range of converters, which include DC voltage converters, voltage rectifiers and autonomous voltage inverters. However, bidirectional key nodes in the power module of the closest analogue do not have a reverse voltage blocking ability, which does not allow this solution to be used in the AC circuit of autonomous current inverters and active rectifiers.

The technical result of the device according to this utility model is the possibility of soft switching in the AC circuits of current converters, when the voltage at the power terminals of the module changes its polarity.

The specified technical result is achieved due to the fact that in the power module containing two series-connected bidirectional current key nodes with a direct voltage blocking ability, and series-connected inductor and first and second capacitors, and one terminal of the first key node is connected to the first power terminal of the module , the other terminal of the first key node is connected to one terminal of the second key node and the output of the throttle, the other terminal of the second key node is connected to the second power the output of the module, the connection point of the first and second capacitors is connected to the third power output of the module, the other output of the second capacitor is connected to one of the first and second power outputs of the module, in accordance with the present utility model, the key nodes of the power module are made with reverse voltage blocking ability.

The utility model is illustrated by the attached drawings, in which the same elements are denoted by the same reference positions.

Figure 1 presents the power module with a multi-resonant circuit and bi-directional current key nodes with forward and reverse blocking voltage.

Figure 2 presents a diagram of the closest analogue.

Figure 3 presents possible options for the practical implementation of bidirectional current key node with forward and reverse blocking voltage.

Figure 4 presents the power module with a multi-resonant circuit and bi-directional current key nodes with forward and reverse blocking voltage, connected to the base switching circuit of the current Converter.

Figure 5 shows three (by the number of phases) power modules with a multi-resonant circuit and bi-directional current key nodes with direct and reverse voltage blocking ability, connected to an alternating current circuit in the current inverter on the cathode group side of the inverter key nodes.

Figure 6 shows three (by the number of phases) power modules with a multi-resonant circuit and bi-directional current key nodes with forward and reverse blocking voltage capability, connected to an alternating current circuit in the current inverter on the side of the anode group of the inverter key nodes.

Figure 7 presents three (by the number of phases) power modules with a multi-resonant circuit and bi-directional current key nodes with forward and reverse voltage blocking ability, connected to an alternating current circuit in the active rectifier on the side of the cathode group of the rectifier key nodes.

On Fig presents three (by the number of phases) power modules with a multi-resonant circuit and bi-directional current key nodes with forward and reverse blocking voltage, connected to an alternating current circuit in the active rectifier on the side of the anode group of key rectifier nodes.

Figure 9 shows the waveform of the soft switching of one of the main key nodes of the current transducer when using a power module with a multi-resonant circuit and bi-directional current key nodes with forward and reverse voltage blocking ability according to the present utility model.

Figure 10 presents the waveform of the soft switching of the first of the bidirectional current key nodes with forward and reverse blocking voltage capacity as part of a power module with a multi-resonance circuit according to the present utility model.

Figure 11 shows the waveform of soft switching of the second of the bi-directional current key nodes with forward and reverse blocking voltage capacity as part of a power module with a multi-resonance circuit according to the present utility model.

On Fig presents a waveform of the voltage on one of the capacitors and the waveform of the current in the inductor as part of a power module with a resonant LCC circuit according to the present utility model.

The power module (Figure 1) contains: a first bi-directional current key assembly 1 with forward and reverse blocking voltage capability, a second bi-directional current key assembly 2 with forward and reverse blocking voltage capability, inductor 3, first capacitor 4 and second capacitor 5. The drawings also show the first power output 6, the second power output 7 and the third power output 8.

The first key node 1 and the second key node 2 are connected in series. The external terminal of the first key node 1 is connected to the first power terminal 6, and the external terminal of the second key node 2 is connected to the second power terminal 7. To the connection point of the first and second key nodes 1, 2 is connected the first terminal of the serial LC circuit formed by the inductor 3 and the first capacitor 4, and the second terminal of the LC circuit is connected to the third power terminal 8. The first terminal of the capacitor 5 is connected to the third power terminal 8, and the second terminal of the capacitor 5 is connected to the first power terminal 6. The second terminal of the capacitor 5 can be and it is also connected to a second power pin 7.

Consider the operation of a power module with a multi-resonant circuit when it is connected to the basic switching circuit, to the circuit of which the current switching processes in current inverters and active current rectifiers are reduced (Figure 4). This circuit contains two unidirectional switches S1 and S2, a current source J and an alternating voltage source E.

First, suppose that the polarity of the voltage of the source E corresponds to that shown in the drawing without brackets (Figure 4).

Suppose also that the source current J flows from the connection point of the main keys S1 and S2 of the converter, while the key S1 is open and the key S2 is closed. When the main key S1 is turned off, the current J is closed through the main key S2.

Then, the output capacitance of the main switch S1 is charged to the voltage of the power source E, and the output capacitance of the main switch S2 is completely discharged. In this case, the capacitor 5 is also charged to the voltage of the power source E with the corresponding polarity.

The initial voltage across the capacitor 4 will be considered equal to U ₀₊ with the polarity shown in the diagram. The absolute value of the voltage U ₀₊ will be determined below at one of the intervals of the switching period.

Imagine the main intervals of soft switching of the load current J from the main switch S2 to the main switch S1 and vice versa.

Before turning on the first main key S1, the second key node 2 of the power module is turned on.

1. The recharge interval of the capacitor 4 in the serial LC circuit.

Through the open second key node 2 and the open main key S2, due to the oscillatory process, the capacitor 4 is recharged to the initial voltage U ₀₊ , but with reverse polarity. The recharge time is equal to half the period of the resonant frequency of the LC circuit:

where Lк is the inductance of the inductor 3; Ck - capacitor 4.

2. The switching interval of the second primary key S2.

After the capacitor 4 is recharged, the current of the inductor 3 begins to increase counter to the load current of the second main switch S2, and when the current value J is reached, this switch is locked at zero current, and a control signal can be removed from it. The duration of the switching interval Δt ₂ is determined by the equation:

- волновое сопротивление последовательного LC контура.Where

- wave impedance of the serial LC circuit.

At the end of the switching interval, the voltage across the capacitor 4 becomes equal to the value U ₀ , which is determined by the equation:

3. The interval of the resonant discharge of the output capacitance of the first main switch S1.

The output capacitance St of the first main key S1 is determined by the capacitance Cx of the capacitor 5, which is chosen much more than the intrinsic output capacitance of the first main key S1:

After locking the second main switch S2, a parallel resonant circuit is formed in the circuit, which includes the current source J, capacitor 5, and also the choke 3 of the serial LC circuit with a serial equivalent voltage source:

where u _Ck (t) is the voltage across the capacitor 4.

In this case, the voltage on the first primary key S1 will change in accordance with the equation:

- круговая частота резонансного процесса перед включением первого основного ключа S1.Where

- the circular frequency of the resonance process before turning on the first main key S1.

The voltage on the capacitor 4 in the serial LC circuit will be equal to:

Equation (6) implies the condition under which, as a result of resonance, a zero voltage is realized on the first main key S1:

Thus, the condition of zero voltage on the first main switch S1 is determined by the voltage U ₀ on the capacitor 4 in the serial LC circuit at the time of switching the second switch S2 for the given parameters of the electric operation mode of the circuit (E and J) and the selected parameters of the multi-resonance circuit (Lк , Ck and Cx).

The duration Δt3 of the resonance interval is determined from equation (6) for u _S1 (t) = 0:

After the interval Δt3, the second main switch S1 can be turned on at zero voltage by applying a control signal to it. In this case, a negative voltage is realized on the second main key S2, equal in magnitude to the voltage E.

4. Interval for the discharge of energy from the resonant inductor 3.

The voltage on the capacitor 4 in the LC circuit after the discharge of the output capacitance of the first main switch S1 becomes equal to:

The current of the inductor 3 in the LC circuit after the discharge of the output capacitance of the first main switch S1 becomes:

- волновое сопротивление мульти-резонансного контура при разряде выходной емкости первого основного ключа S1.Where

- wave impedance of the multi-resonance circuit when discharging the output capacitance of the first main switch S1.

After unlocking the first primary key S1, the serial LC circuit through the open second key node 2 is connected to a power source of circuit E.

Solving the equation of the oscillatory process in the LC circuit, for the inductor current 3 we get:

where β = arctan [(EU _* ) / (ρ _k I _* )].

Integrating (12) over time, for the voltage across capacitor 4 we obtain:

The difference between the current of the inductor 3 and the current J flows first through the output capacitance of the first main switch S1, and then through the switch S1 itself.

When the current of the transistor of the first main switch S1 reaches the current value J, the current of the inductor 3 becomes equal to zero.

Equating (12) to the zero value for the energy release interval Δt4, we obtain:

The voltage on the capacitor 4 in the LC circuit is equal to:

where U _0- = u _Ck (Δt ₄ ).

The voltage across the capacitor 4, equal to U _0- with the polarity opposite to the initial voltage U ₀₊ , can then be used to gently turn off the first main switch S1 at zero current.

5. The interval of conductivity of the load current through the key S1.

This Δt5 time interval is determined by the duration of the open state of the first primary key S1.

6. The interval of the resonant shutdown of the first main switch S1 at zero current.

Before turning off the first main switch S1, a control signal is supplied to the first key node 1 of the power module, and the current i _Lk (t) of the serial LC circuit starts to increase counter to the current J passing through the open first main switch S1:

In this case, the voltage across the capacitor 4 in the LC circuit will change according to the law:

Since the first main switch S1 is in the open state, the voltage across the capacitor 5 is zero. Then, the circular frequency of the resonance process when the first main switch S1 is turned off will be determined by the frequency ω _{to the} sequential LC circuit, which differs from the resonance frequency ω0.

Thus, the oscillatory processes in the LCC circuit of the power module, consisting of a reactor 3, a capacitor 4 and a capacitor 5, are multi-resonant in nature, since they have different resonant frequencies when the main keys S1, S2 of the current converter are turned on and off.

Switching off the first main switch S1 at zero current is possible only if the condition:

At the moment of equal current in the inductor 3 and current J, the current of the first main switch S1 becomes equal to zero, and a control signal can be removed from it.

The duration Δt6 of the interval is determined from equation (16) for a given current J:

At the time when the current in the inductor 3 reaches its maximum value, the voltage across the capacitor 4 again changes its polarity and then increases to the value U _* . This voltage is determined from equation (17) when substituting the time interval Δt6 into it:

The magnitude of the voltage U _* depends on the load current J. But in any case, the voltage U _* will be lower than the initial voltage equal to U ₀₊ . To ensure the stability of the soft switching cycles, it is necessary to raise the voltage level on the capacitor 4 in the LC circuit to the initial value U ₀₊ . To this end, after turning off the first main key S1, the first key node 1 of the power module is left open.

7. The interval of the charge of the capacitor 4 to the voltage of the power source E.

Since the voltage U _* on the capacitor 4 is less than the supply voltage E, the load current cannot flow through the conduction channel of the second main switch S2 because of its unidirectional nature, even if a control pulse is applied to the switch S2. Thus, the only way to close the current J lies through the serial LC circuit and the open first key node 1. In this case, the current J will almost linearly charge the capacitor 4:

The duration of the interval Δt7 of the charge of the capacitor 4 is determined from equation (21) at a voltage on this capacitor equal to E:

8. The interval of the resonant restoration of the initial voltage across the capacitor in the LC circuit.

When the voltage across the capacitor 4 increases to voltage E, the conduction channel of the second main switch S2 is opened. Through this switch S2 and the key node 1 of the power module, the serial LC circuit is connected to the power supply E, and another resonant process with a circular frequency ω _k begins in the circuit. The current in the inductor 3 and the voltage across the capacitor 4 are described in this case by a system of equations:

After a quarter period of the oscillatory process, the current of the inductor 3 changes its direction.

:After another half of the current period of the inductor 3 again reaches zero, while the key node 1 can be turned off at zero current. Thus, the total duration Δt8 of the interval is three quarters of the resonance period equal to

:

Substituting Δt8 into equation (23) for the voltage across capacitor 4 in the LC circuit at the end of the interval, we obtain:

We can assume that the complete cycle of one switching period is completed. And, starting with the voltage U ₀₊ on the capacitor 4, you can start the next cycle.

The larger the current J, the more difficult it is to fulfill the conditions for soft switching of the main keys S1 and S2 of the current converter in accordance with formulas (8) and (18). Therefore, the selection of the values of the elements of the multi-resonance circuit that satisfy the specified conditions should be carried out for maximum load current. For all other current values J below the maximum soft switch condition, the main switches S1 and S2 will be executed automatically.

The dynamic processes in the first and second key nodes 1 and 2 of the considered power module are also soft, and switching occurs at zero current due to a smooth change in current in the oscillatory LC circuit.

In the process of operation of current inverters and active rectifiers, the voltage source E, which enters the switching circuit, changes its polarity. With a change in polarity at the voltage source, the initial conditions in the circuit change. Now, at the initial moment of time, the load current will be closed through the open main switch S1, and switching of the current J from switch S1 to switch S2 should be considered. The output capacity of the main switch S2 at the initial time will be charged to the voltage of the source E with a polarity corresponding to the voltage polarity in brackets (Figure 4).

Since the auxiliary key nodes 1 and 2 of the power module are bi-directional in current and have direct and reverse blocking ability in voltage, all current switching processes between the switches S1 and S2 will have the same main intervals as in the considered version. Now, before turning on the main key S2, you must turn on the first key node 1 of the power module. In this case, the conditions for unlocking the key S2 are provided at zero voltage. Then, after the interval of conductivity of the key S2, it is locked at zero current due to the unlocking of the second key node 2 of the power module.

The principle of operation of the device and the criteria for soft switching do not change with the use of various types of key switches that are used in current converters (GTO and IGCT thyristors, IGBT and IEGT thyristors with insulated gate).

Figure 3 shows possible variants of the circuit implementation of bidirectional current key nodes 1 and 2 with forward and reverse blocking voltage capacity as part of a power module with a multi-resonant circuit.

Next, we consider examples of specific applications of the proposed device.

Figure 5 shows three (by the number of phases) power modules with a multi-resonant circuit and bi-directional current key nodes with direct and reverse voltage blocking ability, connected to the AC circuit in the current inverter on the side of the cathode group of keys of the inverter.

Figure 6 shows three (by the number of phases) power modules with a multi-resonant circuit and bi-directional current key nodes with direct and reverse voltage blocking ability, connected to an alternating current circuit in the current inverter on the side of the anode group of inverter keys.

Figure 7 presents three (by the number of phases) power modules with a multi-resonant circuit and bi-directional current key nodes with forward and reverse blocking voltage capability, connected to an alternating current circuit in the active rectifier on the side of the cathode group of rectifier keys.

On Fig presents three (by the number of phases) power modules with a multi-resonant circuit and bi-directional current key nodes with forward and reverse blocking voltage, connected to the AC circuit in the active rectifier on the side of the anode group of rectifier keys.

Soft switching in these current converters (Figure 5-8) consists in the fact that the first and second power terminals of each of the modules are connected to the terminals of the respective capacitors connected between the phase points in the alternating current circuit of the current converters, which are sources of alternating voltage. In this case, the third power output of the module is connected to the connection point of the “cathodes” or “anodes” of the main keys of the converters, and this point is also the pole of the load current source, the role of which is played by the input current of the inverter or the output current of the current rectifier.

Consider an example of a specific implementation of the device according to this utility model.

The proposed device was designed for a three-phase current inverter, the switching processes in which are calculated using the circuit simulation program PSpice.

Power supply voltage E = 500 V.

Load current J = 40 A.

The main keys of the current inverter are lockable thyristors GTO, voltage class 1200 V, average anode current 100 A, saturation voltage 1.2 V, output capacitance 0.5 nF.

The first and second key nodes 1 and 2 of the power module with a multi-resonant circuit are bi-directional current key nodes with forward and reverse blocking voltage capability, made according to the diode bridge circuit with a transistor switch in its diagonal (Figure 3). Pulse diodes, voltage class 1200 V, average current 60 A, pulse current 500 A, open voltage 1.75 V, recovery time 40 ns. NPT-IGBT type transistor, voltage class 1200 V, average collector current 50 A, pulse collector current 400 A, saturation voltage 2.0 V, output capacitance 0.2 nF.

Choke 3 - inductance 2.0 μH.

Capacitor 4 - capacitance 0.15 μF, voltage 1000 V.

Capacitor 5 - 4.7 nF capacitance, voltage 1000 V.

Figure 9 shows the waveform of the soft switching of one of the main keys of the current transducer when applying a power module with a resonant LCC circuit and bi-directional current key nodes with forward and reverse voltage blocking ability according to the present utility model. The main key of the current inverter turns on at zero voltage and turns off at zero current.

Vertical Scale:

Channel 1: S1 Key Voltage

(voltage across capacitor 5); 400 V / div

Channel 2: key current S1; 50 A / div

Horizontal Scale:

Time - 3 μs / div.

Figure 10 shows the waveform of the soft switching bidirectional current of the first key node 1 with forward and reverse blocking voltage capacity as part of a power module with a resonant LCC circuit according to the present utility model. This first key node 1 turns on and off at zero current.

Vertical Scale:

Channel 1: voltage at key node 1; 400 V / div

Channel 2: current of key node 1; 50 A / div

Horizontal Scale:

Time - 3 μs / div.

Figure 11 shows the waveform of the soft switching bidirectional current of the second key node 2 with direct and reverse blocking voltage capacity as part of a power module with a resonant LCC circuit according to the present utility model. This second key node 2 turns on and off at zero current.

Vertical Scale:

Channel 1: voltage at key node 2; 400 V / div

Channel 2: current of key node 2; 50 A / div

Horizontal Scale:

Time - 3 μs / div.

On Fig presents the waveform of the voltage across the capacitor 4 and the waveform of the current in the inductor 3 as part of a power module with a resonant LCC circuit according to the present utility model. Capacitor 4 restores the initial voltage to the next switching cycle. The current of the inductor 3 determines the soft switching of the first and second key nodes 1 and 2 of the power module at zero current.

Vertical Scale:

Channel 1: voltage across capacitor 4; 400 V / div

Channel 2: inductor current 3; 50 A / div

Horizontal Scale:

Time - 3 μs / div.

Claims (4)

1. A power module comprising two series-connected bi-directional current key nodes with a direct voltage blocking ability and series-connected inductor and first and second capacitors, with one terminal of the first key node connected to the first power terminal of the module, the other terminal of the first key node connected to one terminal of the second key node and the output of the throttle, another terminal of the second key node is connected to the second power terminal of the module, the connection point of the first and second capacitors It is connected to the third power terminal of the module, the other terminal of the second capacitor is connected to one of the first and second power terminals of the module, characterized in that the key nodes of the power module are made with reverse voltage blocking ability. 2. The module according to claim 1, characterized in that the key node contains the first and second key nodes and the first and second diodes, the anode of the first diode and the cathode of the second diode are combined and form one terminal of the key node, the first and second diodes are connected in series with one terminal keys of the same name, the other conclusions of which are combined and form a different output of the key node. 3. The module according to claim 1, characterized in that the key node contains the first and second keys, each equipped with the same counter-parallel diode, the anodes of which are connected, and the cathodes form the terminals of the same name of the key node. 4. The module according to claim 1, characterized in that the key node contains a bridge circuit of four diodes and a key included in the diagonal of the bridge circuit between the connection points of the anodes and cathodes of the corresponding diodes, while the connection points of the anode and cathode of the diodes in another diagonal of the bridge circuit form the conclusions of the key node.

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