CN203086348U - AC voltage stabilizing circuit of no-power transformer - Google Patents

Abstract

The utility model discloses an AC voltage stabilizing circuit without a power supply transformer. The circuit mainly includes a switch circuit, a voltage detection circuit, a rectification circuit, an isolation drive circuit, a synchronous control circuit, a pulse width modulation circuit and a drive circuit. The circuit uses capacitors to store energy, and the voltage synchronous detection circuit controls the pulse width modulation circuit to drive two self-off devices on and off in the positive and negative half cycles of the alternating current, and the voltage detection circuit transmits the detected output voltage value through the photocoupler. For the pulse width modulation circuit, the output pulse width is controlled, and the driving circuit drives the self-shutoff device to realize the pulse width modulation conversion synchronously with the AC voltage waveform, and at the same time, the electric energy stored in the capacitor is superimposed on the grid voltage in the form of voltage to realize Stability of the output AC voltage. The AC voltage stabilizer made of the circuit can reduce the consumption of metal copper and silicon steel sheet resources, reduce the environmental pollution of produced products, and can replace the existing AC voltage stabilizing circuit within a certain range.

Description

AC voltage regulator circuit without power transformer

technical field

The utility model belongs to the field of power electronics technology and equipment, in particular to an AC voltage stabilizing circuit without a power transformer for synchronous conversion of AC by using a power electronics self-shutoff device.

Background technique

The instability of the mains AC power supply voltage during the power supply process will have adverse effects on electrical equipment. Especially when the voltage fluctuates greatly, not only will the electrical equipment fail to work normally, but it may also cause damage to the electrical equipment. AC voltage stabilizer is a voltage stabilizing device that can provide relatively stable working voltage for electrical equipment, and is widely used in equipment in the fields of industrial transportation, national defense, railway and scientific research. Existing AC voltage stabilizers all use a power transformer to adjust the voltage through a control circuit to achieve the purpose of voltage stabilization. As the main component of the AC voltage stabilizer, the power transformer requires a large amount of copper wires and silicon steel sheets during manufacture, and consumes a lot of heat energy when smelting copper wires and silicon steel sheets, so it will consume limited resources and energy greatly; On the one hand, within a certain capacity range, the capacity of the transformer is proportional to its weight (volt-ampere/kg), so AC voltage stabilizers generally have the disadvantages of large volume, heavy weight, and high loss. These deficiencies are particularly prominent in the low-carbon economy currently advocated, so it is an urgent issue to be solved in the field of power electronics technology to find a substitute for transformers under certain scope and conditions by using technical means.

Utility model content

Aiming at the deficiency of the existing AC voltage stabilizer, the technical problem to be solved by the utility model is to provide an AC voltage stabilizing circuit without a power transformer. The circuit uses capacitors to store energy, and uses the turn-off characteristics of power self-turn-off devices (transistors, GTOs, IGBTs and VMOSFETs) in power electronics to form a switching circuit. The pulse width modulation circuit is controlled by the voltage synchronous detection circuit to drive two self-shutoff devices on and off in the positive and negative half cycles of the alternating current, and the voltage detection circuit transmits the detected output voltage value to the pulse width modulation circuit through the optical couple, and the control The output pulse width is driven by the driving circuit to drive the self-shutoff device in the switching circuit to realize the pulse width modulation conversion synchronously with the AC voltage waveform, and at the same time, the electric energy stored in the capacitor is superimposed on the grid voltage in the form of voltage to realize the output AC voltage of stability.

The technical solution of the utility model to solve the technical problem is to design an AC voltage stabilization circuit without a power transformer, which mainly includes a switch circuit, a voltage detection circuit, a rectifier circuit, an isolation drive circuit, a synchronous control circuit, and a pulse width modulation circuit. and drive circuits. The switch circuit is composed of self-turn-off devices T1 and T2, diodes D1, D2, D3 and D4, energy storage capacitors C2 and C3, output filter capacitor C4 and output filter inductor L2; the voltage detection circuit is composed of resistor R and light-emitting tube G1; the rectification circuit is composed of control transformer B and rectification and voltage stabilization circuits E1 and E2; the isolation drive circuit is composed of receiving tube G2`; the pulse width modulation circuit is composed of receiving tube G1` , Controller PWM composition. The control pole b1 of the self-turn-off device T1 in the switch circuit is connected to the output terminal r of the drive circuit, and the cathode of the self-turn-off device T1 is connected to the negative pole of the rectification and voltage stabilization circuit E2 in the rectification circuit connected, the control pole b2 of the self-turn-off device T2 in the switch circuit is connected to the output terminal q of the isolated drive circuit, and the cathode of the self-turn-off device T2 is connected to the rectification and voltage stabilization circuit in the rectification circuit The negative pole of E1 is connected; the output filter inductance L2 in the switch circuit is connected with one end of the resistor R in the voltage detection circuit; the two leads of the primary coil of the control transformer B in the rectifier circuit, one One lead wire is connected to the common terminal N, the other lead wire is connected to the power supply terminal through the filter inductor L1, and the other end of the filter inductor L1 is connected to the filter capacitor C1; the two windings of the secondary coil of the control transformer B are respectively connected to the rectification and voltage stabilization circuit E1 and E2, the positive and negative poles of the rectifying and stabilizing circuit E1 are respectively connected to the isolated drive circuit, and the positive and negative poles of the rectifying and stabilizing circuit E2 are respectively connected to the synchronous control circuit, the pulse width modulation circuit and The drive circuit; the c-terminal of the synchronous control circuit is connected to the a-terminal of the control transformer B in the rectifier circuit, and the b-terminal of the control transformer B is connected to the d-terminal of the synchronous control circuit; synchronous The e end of the control circuit is connected to the g end of the pulse width modulation circuit of the pulse width modulation circuit, the f end of the synchronous control circuit is connected to the h end of the pulse width modulation circuit, and the pulse width The i end of the modulation circuit is connected to the j end of the driving circuit; the light-emitting tube G1 in the voltage detection circuit is coupled with the receiving tube G1' in the pulse width modulation circuit, and the pulse width modulation The circuit is coupled with the receiving tube G2' in the isolated drive circuit via the light emitting tube G2.

In the above solution, the switch circuit is composed of positive and negative half-cycle branches. In the positive half-cycle branch, the negative pole of the diode D1 is connected to one end of the energy storage capacitor C2, and then connected to the self-turn-off device T1 The anode of the capacitor C2 is connected to the common terminal N, the cathode and anode of the self-turn-off device T1 are connected in reverse parallel with a diode D2, the cathode of the self-turn-off device T1 is connected to one end of the output filter inductor L2, and the output The other end of the filter inductor L2 is connected to one end of the output filter capacitor C4, and the other end of C4 is connected to the common terminal N; in the negative half-cycle branch, after the positive pole of the diode D3 is connected to one end of the energy storage capacitor C3, then It is connected to the cathode of the self-turn-off device T2, the other end of the energy storage capacitor C3 is connected to the common terminal, the cathode and the anode of the self-turn-off device T2 are connected in reverse parallel with a diode D4, and the anode of the self-turn-off device T2 is connected to the output One end of the filter inductor L2 and the other end of the output filter inductor L2 are connected to one end of the output filter capacitor C4, and the other end of the output filter capacitor C4 is connected to the common terminal N.

In the above solution, the self-turn-off devices T1 and T2 in the positive and negative half-cycle branches of the switching circuit work synchronously with the AC voltage as follows. In the (0-π) interval of the AC voltage waveform, the pulse width modulation circuit sends out a driving potential starting from 0 and having a pulse width of β, and the self-turn-off device T1 is driven to conduct by the driving circuit ; In the (π-2π) interval of the AC voltage, the pulse width modulation circuit sends out the drive potential with the π point as the starting point and the pulse width as β, and the self-turn-off device T2 is driven through the isolated drive circuit Pass.

In the above scheme, the voltage detection circuit is connected in series with the luminous tube G1 by the resistor R, one end of the resistor R is connected to the output terminal LM, the other end of the resistor R is connected to the anode of the luminous tube G1, and the cathode of the luminous tube G1 is connected to the output terminal LM. The common terminal N of the terminal is connected.

In the above scheme, after the synchronous control circuit takes the synchronous potential of the AC voltage from the terminals a and b of the secondary coil of the control transformer B in the rectifier circuit, the synchronous potential is transmitted to The pulse width modulation circuit is used as a synchronous control voltage for the conduction control of two self-turn-off devices.

In the above solution, the voltage detection circuit will detect the voltage value of the load FZ, and after being coupled by the photocoupler composed of the light-emitting tube G1 and the receiving tube G1`, the voltage signal will be transmitted to the pulse width modulation circuit The controller PWM, the pulse width of the voltage signal is controlled by the controller PWM, the voltage signal is divided into two outputs, and one output is sent to the drive circuit to drive the self-turn-off device T1 switch in the switch circuit; the other output After the voltage signal is coupled by the photocoupler composed of the light-emitting tube G2 and the receiving tube G2', it is transmitted to the isolated drive circuit for amplification, and drives the self-turn-off device T2 in the switch circuit to switch.

The working principle of the circuit: when the circuit is working, the AC power is connected to the input terminal L and the common terminal N, and after being filtered by the input filter circuit composed of the input filter inductor L1 and the input filter capacitor C1, it supplies power for the positive and negative half-cycle branches of the switching circuit . The positive half cycle electric energy of the switching circuit is stored in the energy storage capacitor C2 through the diode D1, and the terminal voltage value of the load FZ detected by the voltage detection circuit is transmitted to The controller PWM in the pulse width modulation circuit, the pulse width modulation circuit outputs a voltage signal starting from the 0 point of the AC voltage waveform and the pulse width is β, and drives the switching circuit in the AC (0-π) interval through the driving circuit The self-turn-off device T1 switches, and at the moment T1 is turned off, the electric energy stored in the inductor L2 is released to the energy storage capacitor C2 through the diode D2; the negative half-cycle electric energy of the switching circuit is stored in the energy storage capacitor C3 through the diode D2, and the voltage detection The terminal voltage value of the load FZ detected by the circuit is transmitted to the controller PWM in the pulse width modulation circuit after being coupled by the photocoupler composed of the light emitting tube G2 and the receiving tube G2`, and the output of the pulse width modulation circuit is in the form of an AC voltage waveform The voltage signal with π point as the starting point and pulse width β drives the self-off device T2 in the switching circuit to switch in the AC (π-2π) interval through the isolated drive circuit. The electric energy is released to the energy storage capacitor C3 through the diode D4. When the grid voltage is lower than the stable voltage value, the electric energy stored in the energy storage capacitors C2 and C3 is superimposed on the voltage of the grid in the form of voltage to reach the rated voltage value; when the grid voltage is higher than the rated voltage value, the self-closing of the switching circuit The conduction time of the breaking devices T1 and T2 will be automatically adjusted to a certain value in the positive and negative half cycles of the AC voltage respectively, and after being filtered by the output filter inductor L2 and the output filter capacitor C4, they will work periodically with the positive and negative half cycle waveforms of the AC voltage. Furthermore, the average value of the AC voltage is stabilized, and the wider the pulse width β, the higher the output voltage.

The filter inductors L1 and L2 also play a role in limiting the instantaneous excessive current in the circuit, so as to protect the self-turn-off device and the diode, and reduce the impact on the power grid at the same time.

The filter inductors L1 and L2 of this circuit have small inductance values and can be made of magnetic rings or porcelain pots made of soft magnetic materials. If the filter inductors L1 and L2 are set as shields, since the circuit does not contain a power transformer, it can resist electromagnetic radiation, and is especially suitable for military electrical equipment against electromagnetic bomb attacks and electromagnetic interference.

Using the AC voltage stabilizing circuit without power supply transformer of the utility model as a unit, after combining multiple units, a multi-phase AC voltage stabilizing circuit without power supply transformer can be obtained.

The utility model is beneficial in that the AC voltage stabilizing circuit without a power supply transformer reduces the volume and weight of the circuit, improves power supply efficiency, and can replace the existing AC voltage stabilizing circuit within a certain range. Because the circuit does not contain a power transformer, the AC voltage stabilizing device made of the circuit can reduce the consumption of metal copper and silicon steel sheet resources, and reduce the environmental pollution of produced products.

Description of drawings:

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is described in further detail.

Figure 1 is the circuit schematic diagram of AC voltage stabilizing device without power transformer

Labels in the figure:

1 switch circuit

2 voltage detection circuit

3 rectifier circuit

4 Isolated drive circuit

5 synchronous control circuit

6 Pulse Width Modulation Circuit

7 drive circuit

Detailed ways

The utility model is an AC voltage stabilizing circuit without a power transformer. Fig. 1 is a schematic circuit diagram of a AC voltage stabilizing device without a power transformer implemented by the utility model. The circuit consists of an input terminal L, a common terminal N, and an input filter Inductor L1, input filter capacitor C1, switch circuit 1, voltage detection circuit 2, rectifier circuit 3, isolation drive circuit 4, synchronous control circuit 5, pulse width modulation circuit 6, drive circuit 7, output filter inductor L2 and output filter capacitor C4 constituted.

When the device is working, the AC power is connected to the input terminal L and the common terminal N, and after being filtered by the input filter circuit composed of the input filter inductor L1 and the input filter capacitor C1, it supplies power to the positive and negative half cycle branches of the switching circuit 1. The positive half cycle electric energy of the switch circuit 1 is stored in the energy storage capacitor C2 through the diode D1, and the terminal voltage value of the load FZ detected by the voltage detection circuit 2 is composed of the light emitting tube G1 and the receiving tube G1` in the pulse width modulation circuit 6 After the optocoupler is coupled, it is passed to the controller PWM in the pulse width modulation circuit 6, and the pulse width modulation circuit 6 outputs a voltage signal with the 0 point of the AC voltage waveform as the starting point and the pulse width as β, and the driving circuit 7 is used in the AC current In the (0-π) interval, the self-turn-off device T1 in the switching circuit 1 is driven to switch. When T1 is turned off, the electric energy stored in the output filter inductor L2 is released to the energy storage capacitor C2 through the diode D2; the switching circuit 1 The negative half-cycle electric energy is stored in the energy storage capacitor C3 through the diode D2, and the terminal voltage value of the load FZ detected by the voltage detection circuit 2 is coupled by the photocoupler composed of the light-emitting tube G2 and the receiving tube G2` in the isolation drive circuit 4 Afterwards, it is sent to the controller PWM in the pulse width modulation circuit 6, and the pulse width modulation circuit 6 outputs a voltage signal with the π point of the AC voltage waveform as the starting point and the pulse width as β. ) interval to drive the self-turn-off device T2 in the switch circuit 1 to switch. When T2 is turned off, the electric energy stored in the output filter inductor L2 is released to the energy storage capacitor C3 through the diode D4.

When the grid voltage is lower than the stable voltage value, the electric energy stored in the energy storage capacitors C2 and C3 is superimposed on the voltage of the grid in the form of voltage to reach the rated voltage value; when the grid voltage is higher than the rated voltage value, the self-closing of the switching circuit The conduction time of the breaking devices T1 and T2 will be automatically adjusted to a certain value in the positive and negative half cycles of the AC voltage respectively, and after being filtered by the output filter inductor L2 and the output filter capacitor C4, they will work periodically with the positive and negative half cycle waveforms of the AC voltage. Furthermore, the average value of the AC voltage is stabilized, and the wider the pulse width β, the higher the output voltage.

The AC voltage stabilizing circuit without power supply transformer of the utility model is used as a unit to combine multiple units to obtain a multiphase AC voltage stabilizing circuit without power supply transformer, and to manufacture a multiphase AC voltage stabilizing device without power supply transformer.

The filter inductors L1 and L2 of the device have small inductance values, and can be made of soft magnetic material magnetic rings or porcelain pots. If the filter inductors L1 and L2 are shielded, the device can resist electromagnetic radiation, and is especially suitable for preventing electromagnetic radiation. Military electrical equipment for bomb and EMI attacks.

The volume and weight of the AC voltage stabilizing device without power transformer made by the utility model are about one fifth of the volume and weight of the existing AC voltage stabilizer; the power supply efficiency is 95-98%, which is higher than that of the existing AC voltage stabilizing device The technical efficiency of the device is more than doubled, and it can replace the existing AC voltage stabilizer within a certain range; it reduces noise and electromagnetic radiation, and can resist electromagnetic interference, especially suitable for military electrical equipment; it reduces the consumption of metal copper and silicon steel sheet resources , Reduce the degree of environmental pollution of the production of products, thereby protecting the environment.

Claims (3)

1. no power supply transformer AC voltage-stabilizing circuit, it is characterized in that: this circuit mainly comprises switching circuit (1), voltage detecting circuit (2), rectification circuit (3), isolated drive circuit (4), synchronization control circuit (5), pulse-width modulation circuit (6) and drive circuit (7); Described switching circuit (1) is made up of two branch roads of positive and negative half period, in the positive half period branch road, the negative pole of diode D1 is with after the end of energy storage capacitor C2 is connected, anode with self-turn-off device T1 is connected again, the other end of capacitor C2 is connected with common port N, the negative electrode of self-turn-off device T1 and anode reverse parallel connection have diode D2, the negative electrode of self-turn-off device T1 is connected to the end of output inductor L2, the other end of output inductor L2 is connected with the end of output filter capacitor C4, and the other end of C4 is connected with common port N; In the negative half-cycle branch road, the positive pole of diode D3 is with after the end of energy storage capacitor C3 is connected, negative electrode with self-turn-off device T2 is connected again, the other end of energy storage capacitor C3 is connected with common port, the negative electrode of self-turn-off device T2 and anode reverse parallel connection have diode D4, the anode of self-turn-off device T2 is connected to the end of output inductor L2, the other end of output inductor L2 is connected with the end of output filter capacitor C4, and the other end of output filter capacitor C4 is connected with common port N.

2. no power supply transformer AC voltage-stabilizing circuit according to claim 1, it is characterized in that: after a end of the secondary coil of the control transformer B of described synchronization control circuit (5) in the described rectification circuit (3) and b hold and take the synchronizing potential of alternating voltage, in the alternating current positive and negative half period, pass to described pulse-width modulation circuit (6) respectively, as the locking control voltage of two self-turn-off device conducting controls.

3. no power supply transformer AC voltage-stabilizing circuit according to claim 1, it is characterized in that: described voltage detecting circuit (2) will detect the magnitude of voltage of load FZ, after the photoelectrical coupler coupling of luminous tube G1 and receiving tube G1` composition, voltage signal is passed to the interior controller PWM of described pulse-width modulation circuit (6), pulse duration by controller pwm voltage signal, voltage signal divides two-way output, and one the tunnel exports to described drive circuit (7) drives the interior self-turn-off device T1 switch work of described switching circuit (1); The voltage signal of another road output is passed to described isolated drive circuit (4) and is amplified after the photoelectrical coupler coupling of luminous tube G2 and adopter G2` composition, drives the self-turn-off device T2 switch work in the described switching circuit (1).

Images