CN103259345B - A kind of contactless power supply system of travelling car of parallel resonance series compensation - Google Patents

Abstract

A non-contact power supply system for a mobile car with parallel resonance series compensation, which is composed of a soft switching power supply, a non-contact power supply primary circuit, and a secondary pickup circuit. The switching power supply is a soft switching power supply, which is composed of a rectifier bridge, a filter circuit, an EMI circuit, an inverter bridge, a switching power supply resonant circuit and a high-frequency transformer. The non-contact power supply primary circuit is composed of filter inductor 14, parallel resonant capacitor 16 and non-contact power supply primary circuit cable 4, etc.; the non-contact secondary pickup circuit is composed of pickup and rectification and voltage stabilization circuit. The advantage of this non-contact power supply system is that a small-capacity IGBT can be used to generate a much larger primary current 22 than the output circuit 20 of the soft-switching power supply 1 through the effect of parallel resonance, which reduces the cost of the soft-switching power supply and improves the system. s efficiency. The soft-switching power supply is used to make the voltage output to the high-frequency transformer close to a sine wave, reducing the cost of the filter. <!--1-->

Description

A non-contact power supply system for mobile cars with parallel resonance and series compensation

technical field

The invention relates to a non-contact power supply system formed by a series-parallel resonance method, belonging to a power supply and charging device for a mobile trolley in the field of non-contact power supply.

Background technique

In order to enable the mobile car to be used in various harsh environments and special environments, and to get rid of the troubles of charging with a charger, replacing the battery, and dragging the power cord of the mobile device, there is an increasing demand for contactless power supply technology (CPS). At present, non-contact power supply devices have gradually become practical and have gradually entered our daily life. The realization of non-contact power transmission technology mainly includes three forms: 1. Inductive coupling type; 2. Radio reception type; 3. Resonance type.

Electrified Monorail System (EMS, Electrified Monorail System), also known as electric monorail conveying system, is an automatic system for conveying and handling goods, combined with machinery, electricity, information and other technologies, it is widely used in automobiles, metallurgy , Electronic products and other large-volume, multi-variety production lines, and also play an important role in the large-scale storage process.

There are currently three power supply methods for the mobile trolley, sliding contact method, cable drag chain method, and battery charging. The disadvantages of these methods are that maintenance is required, the operating cost is relatively high, and the reliability and safety are insufficient in high cleanliness and inflammable and explosive environments. The disadvantages of the above three power supply methods can be effectively overcome by using the non-contact power supply method. The advantages of non-contact power supply are: 1) High mobility, flexibility, no limit to the speed and running distance of the electric car, and it is also suitable for circuits with complex layouts. 2) Low operating cost, one-time investment, almost maintenance-free. 3) High safety: no electrical contact and exposed wires, avoiding potential safety hazards such as electric sparks and electric shocks, and can be used in various harsh environments and special environments. 4) Environmentally friendly: no noise and dust release, eliminating battery-related environmental pollution, green and safe. 5) High reliability: the system has no physical friction, avoiding physical loss and chemical corrosion, and reliable operation is guaranteed.

The non-contact power supply of the present invention belongs to the inductive coupling type. Its principle is that the primary side coil and the secondary side coil are adjacent to each other for a certain distance, and a high-frequency AC large current is added to the primary side coil, and the electromagnetic field is used as a medium to induce in the secondary side coil. The electromotive force is generated, and after rectification, filtering, and voltage stabilization, the mobile terminal is powered or charged, thereby realizing power transmission. The primary side coil can be laid along the running track of the mobile trolley, or laid on the fixed charging position of the mobile trolley. The secondary coil is wound on an E-shaped or U-shaped ferrite core and installed on the mobile trolley. In order to reduce cost and improve efficiency, the present invention adopts the method of parallel resonance and series compensation to form a non-contact power supply system.

Contents of the invention

In order to take advantage of the superior characteristics of the non-contact power supply and expand its application range, the problem to be solved by the present invention is to reduce the cost of the non-contact power supply system and improve its power transmission efficiency. Technical scheme of the present invention is as follows:

A non-contact power supply system for an electric mobile car, which consists of a soft switching power supply (including an optional high-frequency isolation transformer, a non-contact power supply primary side circuit (composed of a primary side compensation circuit and a primary side laid along the moving track or charging position of the mobile car) Circuit composed of cables), non-contact power supply secondary side circuit.

The soft switching power supply of the present invention is mainly composed of a rectifier bridge, a filter circuit, an EMI circuit, an inverter bridge, a switching power supply series resonant inductor, a switching power supply series resonant capacitor and a high-frequency isolation transformer, etc., and its function is to generate a non-contact power supply primary side circuit The required high-frequency power supply and isolation. The use of soft switching power supply not only improves the efficiency of the switching power supply, but also makes the input and output voltage of the high frequency transformer close to the sine wave, simplifies the structure of the filter required for the primary side circuit of the non-contact power supply, reduces the system cost, and improves the efficiency. system efficiency.

The magnetic core of the high-frequency isolation transformer can be considered to use ultrafine crystal material and ferrite, and the coil is made of enamelled stranded wire (Litz-wire) to overcome the skin effect and reduce loss.

The non-contact power supply primary side circuit of this system, the cable of the primary side circuit is the load of the primary side circuit, which is laid along the running track of the mobile car, or laid at the fixed charging position of the mobile car. The series connection of the parallel resonant capacitor, the small current-limiting inductance, the additional inductance/compensation capacitor and the cable of the primary side circuit constitutes a parallel resonant circuit. The additional inductor/compensation capacitor is an optional device. When the cable of the primary side circuit is relatively short and its inductance is small, an additional inductance needs to be connected in series so that the inductive reactance connected in series with the primary side cable is equal to the capacitive reactance of the parallel resonant capacitor 16, which satisfies the parallel resonance condition; when the primary side circuit When the cable is relatively long, its inductance is large, and a series compensation capacitor is required to offset a part of the inductive reactance of the primary cable to meet the parallel resonance condition. When the cable length of the primary side circuit is very long, limited by the withstand voltage and cost of the compensation capacitor, multiple compensation capacitors can be connected in series to achieve the resonance condition. The small current-limiting inductance prevents high-order harmonic current from being injected into the parallel resonant capacitor, so as to protect the parallel resonant capacitor from overcurrent. The function of the filter inductor is to filter out the harmonics of the switching power supply and reduce the voltage harmonics added to the parallel resonant capacitor and the current-limiting small inductance branch. The change of the cable parameters of the primary circuit caused by the load, as well as the change of the capacitance of the parallel resonant capacitor and the compensation capacitor caused by the temperature, etc., make the circuit out of the resonance point, and it is solved by automatically adjusting the frequency of the switching power supply.

Since the primary side circuit of the non-contact power supply system requires high frequency and large current, parallel resonance is used in the system design. The purpose is to use the capacitive current in the parallel resonant capacitor to compensate the inductive current in the cable of the primary side circuit, which is a parallel resonant circuit. The phase relationship of each current, the phase difference between the capacitor current and the inductor current is close to 180°C. Under the condition of resonance, although the current in the cable of the primary side circuit and the parallel resonant capacitor is relatively large, the output current of the switching power supply is the same as the output current of the switching power supply. The voltages are in the same phase, but the active current consumed by this system is far less than the current value required by the cables of the primary circuit. The capacity of the switching power supply can be designed according to the load and the power consumed by the system. The capacity of the switching tube, the high-frequency isolation transformer and the filter inductor etc. are greatly reduced, and the system cost is greatly reduced. Adjust the design parameters so that the current of the parallel resonant capacitor and the inductance current in the cable of the primary side circuit are much larger than the output current of the switching power supply, and when the switching power supply outputs a relatively small current, a large non-contact power supply system can be generated. Side current to induce relatively large power.

The non-contact power supply secondary side circuit of this system is composed of a pickup and a rectification, filtering and voltage stabilizing circuit. The pickup coil is connected to a rectifier bridge composed of ultra-fast recovery diodes through a π-type filter. The π-type filter consists of inductors, capacitors, and capacitors to filter out high-frequency harmonics. The DC output from the rectifier bridge is filtered by inductors and capacitors, and then a high-quality DC voltage is obtained through a voltage stabilizing circuit for use by the load.

Through the effect of parallel resonance, the present invention can generate a relatively large current required by the primary side of the non-contact power supply, and can even generate a primary current of the non-contact power supply several times larger than the nominal current of the IGBT used in the soft-switching power supply, while the soft-switching power supply The output current is only relatively small active current. The cost of soft switching power supply, high-frequency isolation transformer and filter inductor is effectively reduced, and the efficiency of the system is improved. Due to the use of soft-switching power supply, the voltage output to the high-frequency transformer is close to a sine wave, which simplifies the design of the filter, and even a good sine wave can be obtained with only the filter inductor, reducing its cost and energy loss.

Description of drawings

Fig. 1 is the overall structural diagram of the non-contact power supply of the mobile trolley according to the present invention

Figure 2 is a schematic diagram of the soft switching power supply.

Figure 3 is a circuit diagram of the primary side of the non-contact power supply.

Fig. 4 is a vector diagram illustrating the parallel resonance of the non-contact power supply primary circuit diagram.

Fig. 5 is a circuit diagram of the secondary side of the non-contact power supply.

In the figure: 1 soft switching power supply, 2 high-frequency isolation transformer, 3 non-contact power supply primary side compensation circuit, 4 non-contact power supply primary circuit cable, 5 non-contact power supply secondary circuit, 6 mains power supply, 7 rectifier bridge, 8 Filter circuit, 9EMI circuit, 10 inverter bridge, 11IGBT, 12 switching power supply series resonance inductor, 13 switching power supply series resonance capacitor, 14 filter inductor, 15 current limiting small inductor, 16 parallel resonance capacitor, 17 additional inductor, 18 compensation capacitor, 19 The current of the parallel resonant capacitor, 20 The output current of the switching power supply, 21 The output voltage of the switching power supply, 22 The inductance current in the cable 4 of the primary side circuit, 23 The pickup coil, 24, 26 π-type filter capacitor, 25 π-type filter Inductance, 27 secondary circuit rectifier bridges, 28 secondary circuit filter inductors, 29 secondary circuit filter capacitors, 30 voltage regulator circuits.

Detailed ways

Specific embodiments of the present invention will be described in detail below through technical solutions and accompanying drawings.

This embodiment is a 10kW mobile car non-contact power supply system, which is mainly divided into soft switching power supply, non-contact power supply primary side circuit, and non-contact power supply secondary side circuit.

The soft switching power supply is shown in Figure 1. The power supply adopts a three-phase 380 volt AC power supply 6, which consists of a rectifier bridge 7, a filter circuit 8, an EMI circuit 9, an inverter bridge 10, a switching power supply series resonant inductor 12, and a switching power supply series resonant capacitor. 13 and high-frequency transformer 2 etc., its function is to produce the high-frequency power required by the primary side circuit of the non-contact power supply and play an isolation role. Among them, the resonant frequency of the switching power supply series resonant inductor 12 and the switching power supply series resonant capacitor 13 is designed to be 20kHz, and the operating frequency of the soft switching power supply is adjustable at 30kHz, that is, the operating frequency of the switching power supply is higher than the working mode of the resonant frequency. The working mode of continuous current is suitable for the needs of non-contact power supply primary side circuit.

The primary side circuit of the non-contact power supply is shown in Figure 3. In this example, the filter inductor 14 uses a metal magnetic powder core as the magnetic core, and Litz wire as the coil winding. In this example, the current of the non-contact power supply primary side circuit is designed to be an effective value of 100A, and the frequency is 30kHz. The output voltage of the secondary side of the high-frequency transformer is a sine wave with an effective value of 180V after being filtered by the filter inductor 14 . The capacity of the parallel resonant capacitor 16 is selected as 3 μF, and the small current-limiting inductor 15 connected in series with the parallel resonant capacitor is selected as 0.5 μH. In order to illustrate the effectiveness of the invention, two lengths of the non-contact power supply primary side circuit cable 4 are selected: 20 meters and 40 meters, and are arranged beside the track where the self-propelled trolley runs. The measured inductance with a length of 20 meters is 9.7μH, and when the operating frequency of the switching power supply is 29.5kHz, it reaches a resonance state. In this case, neither the additional inductance 17 nor the compensation capacitor 18 in FIG. 3 needs to be added. The measured inductance of a cable with a length of 40 meters is 19.3 μH. At this time, the compensation capacitor 18 in the accompanying drawing 3 needs to be added, so that the series inductance of the compensation capacitor 18 and the primary side circuit cable 4 is about 9.7 μH. At 29.4kHz, a resonance state is reached. In practical applications, the inductance of the primary circuit cable 4, the capacitance of the parallel resonant capacitor 16 and the additional capacitor 18, etc. will be changed due to the influence of the environment, etc. The switching power supply in this example can automatically detect whether the primary circuit is working In the resonant state, and adjust the operating frequency at any time to make the circuit work in the resonant state. In order to make it possible to work in a state close to resonance, the power tube IGBT of the switching power supply can be selected to be larger.

The non-contact power supply secondary side circuit is shown in Figure 5, the inductance 23 in the figure is a pickup coil, which is composed of an E-type ferrite core and a winding wound on the middle column of the E-type core. Because the voltage waveform of the primary side is better, the induced voltage waveform of the measured pickup coil 23 is a smooth sine wave, so the output of the pickup coil 23 is directly connected to the rectifier bridge 27 made of ultra-fast recovery diodes, through the inductance 28 and the capacitor 29 The filter is direct current, and then a constant direct current power is output through the voltage stabilizing circuit 30 for use by the mobile trolley.

Claims (2)

1. A non-contact power supply system for a mobile car with parallel resonance series compensation, the non-contact power supply system includes a high-frequency soft switching power supply (1), a non-contact power supply primary circuit (3) and a non-contact power supply secondary circuit (5 ), characterized in that, The primary side circuit of the non-contact power supply is a parallel resonant circuit, and the high-frequency soft switching power supply is added to the parallel resonant circuit through a high-frequency inductive filter as a power supply. The high-frequency soft switching power supply adopts a three-phase 380 volt AC power supply (6), Including rectifier bridge (7), filter circuit (8), EMI circuit (9), inverter bridge (10), switching power supply series resonant inductor (12), switching power supply series resonant capacitor (13) and high frequency transformer (2) ; Parallel resonant capacitor (16), current-limiting small inductance (15) and additional inductance (17)/compensation capacitor (18) and primary side circuit cable (4) in series to form a parallel resonant circuit; when non-contact power supply primary side circuit cable When it is relatively long, its inductance is large, and at least one compensation capacitor is connected in series to offset the inductive reactance of a part of the circuit cable to meet the parallel resonance condition; The non-contact power supply secondary circuit is composed of a pickup coil, a rectifier bridge, a filter circuit, and a voltage stabilizing circuit; The pickup coil is an inductance, mainly composed of an E-type ferrite core and a winding wound on the middle column of the E-type core; the output of the pickup coil is directly connected to a rectifier bridge (27) composed of an ultra-fast recovery diode , filtered by the inductance (28) and the capacitor (29) into a direct current, and then through the voltage stabilizing circuit (30) to output a constant direct current power supply for the mobile car. 2. The non-contact power supply system for the mobile car according to claim 1, characterized in that the operating frequency range of the soft switching power supply is 10kHz-60kHz.