Found an interesting part here.
http://www.indiadivine.org/content/topic/982745-yoga-maya-maha-maya-subhadra-durga/
The Yogamaya is the principal potency of the Personality of Godhead. In the Vedas it is stated that the Lord, the Supreme Personality of Godhead, has multipotencies. Parasya saktir vividhaiva sruyate. All the different potencies are acting externally and internally, and Yogamaya is the chief of all potencies. He ordered the appearance of Yogamaya in the land of Vrajabhumi, in Vrndavana, which is always decorated and full with beautiful cows.
__ Krishna Book Chp2 {Prayers by the Demigods for Lord Krsna in the Womb}
Same Chapter:
"Since you will appear as My contemporary sister, people within the world will worship you with all kinds of valuable presentations: incense, candles, flowers and offerings of sacrifice. You shall quickly satisfy their desires for sense gratificiation. People who are after materialistic affection will worship you under the different forms of your expansions, which will be named Durga, Bhadrakali, Vijaya, Vaisnavi, Kumuda, Candika, Krsna, Madhavi, Kanyaka, Maya, Narayani, Isani, Sarada and Ambika."
Krsna and Yogamaya appeared as brother and sister--the Supreme Powerful and the supreme power. Although there is no clear distinction between the Powerful and the power, power is always subordinate to the Powerful. Those who are materialistic are worshipers of the power, but those who are transcendentalists are worshipers of the Powerful. Krsna is the Supreme Powerful, and Durga is the supreme power within the material world. Actually people in the Vedic culture worship both the Powerful and the power. There are many hundreds of thousands of temples of Visnu and Devi, and sometimes they are worshiped simultaneously. The worshiper of the power, Durga, or the external energy of Krsna, may achieve all kinds of material success very easily, but anyone who wants to be elevated transcendentally must engage in worshiping the Powerful in Krsna consciousness
Else where:
Subhadra is yogamaya. The spiritual energy is called yogamaya. And she has 16 different expansions. Out of these 16 expansions, Subhadra is one. The mahamaya of the material energy is also expansion of the energy of yogamaya; and both yogamaya and mahamaya are equally important to Krishna as much as any government department is equally important for functioning of the government. The police department may be horrible for the criminals, but to the government it is a department as good as university department. Similarly, mahamaya is horrible to the conditioned soul, but to the liberated soul, there is no fear of mahamaya, because he is protected by yogamaya. It is stated in the Bhagavad-gita when Krishna said the following: ''I am not visible to everyone on account of being curtained by yogamaya.'' So when a conditioned soul surrenders unto Krishna, the yogamaya winds up the curtain and Krishna is visible to the devotee.
Regarding your question about Subhadra and Durga, they are not at all the same. Durga's other name is Bhadra, not Subhadra, and Durga's activities are within the material world. Subhadra does not work as Durga. Subhadra is internal energy, and Durga is external energy. As energy, they have a relationship as much as we are energies of Krishna, but the energies are working in different capacities. Although originally the energy is one, by their expansion, the accents of the energies are different, and as we are not impersonalists, this variegatedness of actions are essential for the Supreme Personality of Godhead, as much as the government is one but there are multi-departments for management of the government. The education department and the criminal department are all departments of the government. The government is connected with all parts and departments, but the education activities are different from the criminal activities. This is the philosophy of inconceivably simultaneously one and different manifestations of the Absolute Truth.
Kumkum Bhagya
