Background
As energy saving and carbon reduction and environmental protection are concerned, all countries around the world are dedicated to developing green power generation which is beneficial to the environment, and the problem of green power generation is how to store the generated power. In addition, in a typical power plant, the amount of power generated by the generator set is increased during peak periods of the power consumption concentration of the users, and the amount of power generated is decreased during off-peak periods. However, the off-peak power cannot be retained until the peak time, which often results in insufficient power generation of the power plant during the peak time, and more power generation of the power generating set is required to respond to the peak time.
For this reason, a power supply system has been developed in a workshop, which can store the electric power of a power plant or a green energy power generation device in a battery, and can convert the dc electric energy stored in the battery into ac electric energy to be output to a load for use.
Fig. 1 shows a conventional power supply system 1, which includes an energy storage device 10 and a power conversion device 20, wherein the energy storage device 10 includes a first housing 12, a plurality of storage batteries 14, an anode 16 and a cathode 18, the first housing 12 is made of metal, and the plurality of storage batteries 14 are located in the first housing 12 and electrically connected to the anode 16 and the cathode 18. The power conversion device 20 includes a second housing 22 and a conversion module 24, the second housing 22 is made of metal and is electrically connected to the first housing 12 to form a common ground, the conversion module 24 is disposed in the second housing 22, the conversion module 24 is electrically connected to the positive electrode 16 and the negative electrode 18 of the energy storage device 10, the conversion module 24 is electrically connected to the ac power source 100 and the load 200, and the conversion module 24 is configured to convert ac power and dc power to charge the storage battery 14 of the energy storage device or convert dc power from the energy storage device 10 into ac power to supply power to the load 200.
Since the conversion module 24 generates noise during power conversion, the generated noise is transmitted to the energy storage device 10 through the second housing 22 and transmitted to the positive electrode 16 and the negative electrode 18 through the conversion module 24, and thus the voltage detection element, the current detection element, or the temperature detection element inside the energy storage device 10 is interfered to affect the detection result, and the detection is misaligned.
In addition, since the energy storage device 10 communicates with the power management device 400 through the communication interface 300, the electrical signal transmitted by the energy storage device 10 on the communication interface 300 is interfered by the noise generated by the converting module 24, and thus an error occurs.
Therefore, the design of the conventional power supply system 1 is still not perfect and needs to be improved.
Detailed Description
In order to more clearly illustrate the present invention, preferred embodiments are described in detail below with reference to the accompanying drawings. Referring to fig. 2 to 4, a power supply system 2 according to a first preferred embodiment of the present invention includes an energy storage device 30, a power conversion device 40, a first noise suppression circuit 50 and a second noise suppression circuit 60, wherein:
the energy storage device 30 includes a first housing 32, a plurality of batteries 34, an anode 362 and a cathode 364, the first housing 32 is made of metal, the plurality of batteries 34 are disposed in the first housing 32, and the anode 362 and the cathode 364 are electrically connected to the plurality of batteries 34. The positive electrode 362 and the negative electrode 364 output a direct current. In this embodiment, the voltage of the direct current is more than 600V, and the energy storage device 30 may further include a detection module 38, the detection module 38 is electrically connected to the plurality of storage batteries 34, the detection module 38 may include a plurality of voltage detection elements, a plurality of current detection elements and a plurality of temperature detection elements, and the detection module 38 detects states of the plurality of storage batteries 34, such as voltage, current, temperature, and the like, respectively.
The power conversion apparatus 40 includes a second housing 42 and a conversion module 44, the second housing 42 is made of metal and electrically connected to the first housing 32, and the first housing 32 and the second housing 42 are commonly grounded. The converting module 44 is disposed in the second housing 42, the converting module 44 is electrically connected to the positive electrode 362 and the negative electrode 364, and the converting module 44 can operate in one of a first converting mode and a second converting mode, wherein when the converting module 44 operates in the first converting mode, the converting module receives the ac power from the external ac power source 100 and converts the dc power to output to the positive electrode 362 and the negative electrode 364, so as to charge the battery 34 in the energy storage device 30.
When the converting module 44 operates in the second converting mode, the direct current from the positive electrode 362 and the negative electrode 364 is converted into an alternating current and then output to an external load 200, so as to supply power to the load 200. The conversion module 44 further includes a switching circuit 442, the switching circuit 442 is composed of a plurality of switching elements, such as transistors, and when the conversion module 44 operates in the first conversion mode, the switching circuit 442 operates at a switching frequency to repeatedly switch and convert the dc power into ac power.
The energy storage device 30 and the power conversion device 40 can also communicate with a power management device 400 through a communication interface 300 to transmit electrical signals carrying status data, control commands, etc. through the communication interface 300.
The first noise suppression circuit 50 is electrically connected between the anode 362 and the first housing 32, and the first noise suppression circuit 50 is configured to filter noise between the anode 362 and the first housing 32. The second noise suppression circuit 60 is electrically connected between the negative electrode 364 and the first housing 32, and the second noise suppression circuit 60 is used for filtering noise between the negative electrode 364 and the first housing 32.
In this embodiment, the first noise suppression circuit 50 and the second noise suppression circuit 60 are at least used for filtering the noise generated when the conversion module 44 operates in the second conversion mode, and preferably used for filtering the noise (e.g. harmonic) of the frequency multiplication of at least 2 times of the switching frequency. For example, when the switching frequency is 10KHz, the first noise suppression circuit 50 and the second noise suppression circuit 60 filter out the noise of the frequency multiplication above 20 KHz. But not limited to this, it can also be designed to filter the noise of frequency multiplication more than 3 times or more than 4 times.
Referring to fig. 3, the first noise suppression circuit 50 of the present embodiment includes a parallel circuit P connected between the anode 362 and the first housing 32, the parallel circuit P is formed by a capacitor C and a resistor R connected in parallel, for example, the capacitor C may be a capacitor with a withstand voltage of more than 600V, such as 620V or 750V, the capacitance may be 10 μ F, the resistance of the resistor R may be 2M ohm, and the power may be 4W. In practice, the capacitor may be formed by connecting a plurality of capacitors C and a plurality of resistors R in parallel.
Referring to fig. 4, the second noise suppression circuit 60 includes a parallel circuit P connected between the cathode 364 and the first housing 32, the parallel circuit P is formed by connecting a capacitor C and a resistor R in parallel, and the specifications of the capacitor C and the resistor R can be the same as those of the first noise suppression circuit 50, which is not repeated.
With the above structure, when the converting module 44 generates noise, the resistors R of the first and second noise suppressing circuits 50 and 60 can consume part of the power of the noise to eliminate part of the noise. The capacitor C and the resistor R form a filter circuit, which can filter out the noise of frequency multiplication more than 2 times, especially suppress the noise of frequency multiplication generated when the converting module 44 operates in the second converting mode. Therefore, noise generated by the conversion module 44 can be effectively suppressed from being transmitted into the energy storage device 30 through the first housing 32, the positive electrode 362 and the negative electrode 364.
Therefore, it is effectively avoided that the noise of the converting module 44 interferes with the energy storage device 30, so that the detection result of the detecting module 38 of the energy storage device 30 is inaccurate. And also to avoid interfering with the communication between energy storage device 30 and power management device 400.
In addition, in this embodiment, at least one capacitor Co is further connected between the anode 362 and the cathode 364, two ends of the capacitor Co are respectively electrically connected between the anode 362 and the cathode 364, the withstand voltage of the capacitor Co is more than 600V, and the capacitance value can be 1 μ F. The capacitor Co can stabilize the voltage between the anode 362 and the cathode 364, and prevent the voltage between the anode 362 and the cathode 364 from floating.
Fig. 5 shows a first noise suppression circuit 70 of the power supply system according to the second preferred embodiment of the present invention, wherein the first noise suppression circuit 70 includes two parallel circuits P, and the plurality of parallel circuits P are connected in series between the positive electrode 362 and the first housing 32. By using two parallel circuits P, a capacitor C with a lower withstand voltage and a resistor R can be selected, the withstand voltage of the capacitor C can be more than 300V, for example, 310V, the capacitance can be 20 muF, the resistance of the resistor R can be 1M ohm, and the power can be 2W. In practice, the first noise suppression circuit 70 may also include more than two parallel circuits P connected in series between the positive electrode 362 and the first housing 32.
The second noise suppression circuit of the second preferred embodiment may have the same circuit structure as the first noise suppression circuit 70, and may also have a plurality of parallel circuits P connected in series between the negative electrode 364 and the first housing 32.
According to the invention, the first noise suppression circuit is connected between the anode of the energy storage device and the first case, and the second noise suppression circuit is connected between the cathode and the first case, so that noise generated by the power conversion device can be effectively suppressed from being transmitted to the first case, the anode and the cathode, and the noise is prevented from interfering with the energy storage device.
The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications to the present invention as described and claimed should be included in the scope of the present invention.
Description of the reference numerals
[ conventional ]
1 … power supply system
10 … energy storage device
12 … first case
14 … accumulator
16 … positive pole
18 … negative electrode
20 … power conversion device
22 … second casing
24 … conversion module
[ invention ]
2 … electric power supply system
30 … energy storage device
32 … first case
34 … accumulator
362 … positive pole
364 … negative electrode
38 … detection module
40 … power conversion device
42 … second casing
44 … conversion module
442 … switching circuit
50 … first noise suppression circuit
60 … second noise suppression circuit
70 … first noise suppression circuit
P … parallel circuit
C … capacitance
Co … capacitance
R … resistor
100 … AC power supply
200 … load
300 … communication interface
400 … power management device